Biology (Non-Majors) (Fall 2014) Test #1

Front 1

The chief taxonomic category. This book recognizes six ________: Archaea, Bacteria, Protista, Fungi, Animalia, and Plantae.

Back 1

1. Kingdoms (16)

Front 2

A group of prokaryotes that are among the most primitive still in existence, characterized by the absence of peptidoglycan in their cell walls, a feature that distinguishes them from bacteria. This kingdom of prokaryotes (the simplest of cells that do not have nuclei) includes this methanogen (picture in book), which manufactures methane as a result of its metabolic activity.

Back 2

1. Archaea Kingdom (16)

Front 3

The most common type of prokaryotic organism. Cell walls contain peptidoglycan. Play many important ecological roles. This group is the second of the two prokaryotic kingdoms. Show here (image in book) are purple sulfur bacteria, which are able to convert light energy into chemical energy.

Back 3

1. Bacteria Kingdom (16)

Front 4

Includes unicellular eukaryotic organisms and some multicellular lines derived from them. Most of the unicellular eukaryotes (those whose sells contain a nucleus) are grouped into this kingdom, and so are the multicellular algae pictured here (image in book).

Back 4

1. Protista Kingdom (16)

Front 5

This kingdom contains nonphotosynthetic organisms, mostly multicellular, that digest their food externally, such as these mushrooms (picture in book).

Back 5

1. Fungi Kingdom (16)

Front 6

This kingdom contains photosynthetic multicellular organisms that are terrestrial, such as the flowering plant pictured here (image in book).

Back 6

1. Plantae Kingdom (16)

Front 7

Organisms in this kingdom are nonphotosynthetic multicellular organisms that digest their food internally, such as this ram (picture in book).

Back 7

1. Animalia Kingdom (16)

Front 8

All living things are composed of one or more cells. A cell is a tiny compartment with a thin covering called a membrane. Some cells have simple interiors, while others are complexly organized, but all are able to grow and reproduce. Many organisms possess only a single cell; your body contains from 10 – 100 trillion cells (depending on how big you are).

Back 8

1. Cellular Organization (17)

Front 9

The process by which all living things assimilate energy and use it to grow. The transfer of energy from one form to another in cells is an example of __________.

Back 9

1. Metabolism (17)

Front 10

The maintaining of a relatively stable internal physiological environment in an organism or steady-state equilibrium in a population or ecosystem.

Back 10

1. Homeostasis (17)

Front 11

All living things grow and reproduce. Bacteria increase in size and simply split in two as often as every 15 minutes, while more complex organisms grow by increasing the number of cells and reproduce sexually.

Back 11

1. Growth and Reproduction (17)

Front 12

The transmission of characteristics from parent to offspring.

Back 12

1. Heredity (17)

Front 13

At the level or position of the most basic structural and functional units of the human body; cells are organized into five levels of complexity (atoms, molecules, macromolecules, organelles, and cells).

Back 13

1. Cellular Level (18)

Front 14

A core (nucleus) of protons and neutrons surrounded by an orbiting cloud of electrons. The chemical behavior of an ____ is largely determined by the distribution of its electrons, particularly the number of electrons in its outermost level.

Back 14

1. Atoms (18)

Front 15

The smallest unit of a compound that displays the properties of that compound.

Back 15

1. Molecules (18)

Front 16

An extremely large molecule. Refers specifically to carbohydrates, lipids, proteins, and nucleic acids.

Back 16

1. Macromolecules (18)

Front 17

A specialized compartment of a cell. Mitochondria are __________.

Back 17

1. Organelles (18)

Front 18

The smallest unit of life. The basic organizational unit of all organisms. Composed of a nuclear region containing the herediary apparatus within a larger volume called the cytoplasm bounded by a lipid membrane.

Back 18

1. Cells (18)

Front 19

Cells are organized into four levels of complexity (tissues, organs, organ systems, and organism).

Back 19

1. Organismal Level (18)

Front 20

A group of similar cells organized into a structural and functional unit.

Back 20

1. Tissues (18)

Front 21

A complex body structure composed of several different kinds of tissue grouped together in a structural and functional unit.

Back 21

1. Organs (19)

Front 22

A group of organs that function together to carry out the principal activities of the body.

Back 22

1. Organ Systems (19)

Front 23

Any individual living creature, either unicellular or multicellular.

Back 23

1. Organism (19)

Front 24

Organisms are organized into four hierarchical levels within the living world (population, species, community, and ecosystem).

Back 24

1. Populational Level (19)

Front 25

Any group of individuals of a single species, occupying a given area at the same time.

Back 25

1. Population (19)

Front 26

A group of interbreeding organisms that are reproductively isolated from all other such groups; a taxonomic unit ranking below a genus and designated by a two-part scientific name consisting of its genus and the species name.

Back 26

1. Species (19)

Front 27

The populations of different species that live together and interact in a particular place.

Back 27

1. Community (19)

Front 28

A community together with the nonliving factors with which it interacts.

Back 28

1. Ecosystem (19)

Front 29

Novel properties in the hierarchy of life that were not present at the simpler levels of organization.

Back 29

1. Emergent Properties (19)

Front 30

The differential reproduction of genotypes caused by factors in the environment. Leads to evolutionary change.

Back 30

1. Natural Selection (20)

Front 31

The breeding of plants and animals to produce desirable traits. Organisms with the desired traits, such as size or taste, are artificially mated or cross-pollinated with organisms with similar desired traits.

Back 31

1. Artificial Selection (20)

Front 32

The condition in which two or more dissimilar organisms live together in close association; includes parasitism, commensalism, and mutualism.

Back 32

1. Symbiosis (20)

Front 33

Making individual decisions by applying a “guide” of accepted general principles. A logical process in which a conclusion drawn from a set of premises contains no more information than the premises taken collectively. All dogs are animals; this is a dog; therefore, this is an animal: The truth of the conclusion is dependent only on the method.

Back 33

1. Deductive Reasoning (22)

Front 34

Through observation, scientists look at the world to understand how it works and determine the principles that govern our physical world. Reasoning in which the premises seek to supply strong evidence for (not absolute proof of) the truth of the conclusion.

Back 34

1. Inductive Reasoning (22)

Front 35

Any of several simple gaseous compounds that contain carbon, chlorine, fluorine, and sometimes hydrogen, that are used as refrigerants, cleaning solvents, and aerosol propellants and in the manufacture of plastic foams, and that are believed to be a major cause of stratospheric ozone depletion.

Back 35

1. Chlorofluorocarbons (CFCs) (23)

Front 36

A proposal that might be true. No __________ is ever proven correct. All __________ are provisional – proposals that are retained for the time being as useful but that may be rejected in the future if found to be inconsistent with new information. A __________ that stands the test of time – often tested and never rejected – is called a theory.

Back 36

1. Hypothesis (24)

Front 37

The test of a hypothesis. An __________ that tests one or more alternative hypotheses and those that are demonstrated to be inconsistent with experimental observation are rejected.

Back 37

1. Experiment (24)

Front 38

The key to any successful scientific investigation is careful ___________. The action or process of _________ something or someone carefully or in order to gain information.

Back 38

1. Observation (24)

Front 39

Formed when scientists have more than one guess about what they observe; (in the statistical testing of a __________) the __________ to be accepted if the null __________ is rejected.

Back 39

1. Alternative Hypotheses (25)

Front 40

What you expect to happen if a hypothesis is true.

Back 40

1. Predictions (25)

Front 41

Attempting to verify the hypothesis’ predictions.

Back 41

1. Testing (25)

Front 42

A group or individual used as a standard of comparison for checking the results of a survey or experiment.

Back 42

1. Controls (25)

Front 43

Any factor that influences a process. In evaluating alternative hypotheses about one ________, all other _________ are held constant so that the investigator is not misled or confused by other influences.

Back 43

1. Variable (25)

Front 44

An __________ where all subjects involved are treated exactly the same except for one deviation.

Back 44

1. Control Experiment (25)

Front 45

A hypothesis that has been tested and not rejected is tentatively accepted.

Back 45

1. Conclusion (25)

Front 46

A well-tested hypothesis supported by a great deal of evidence.

Back 46

1. Theory (25)

Front 47

A method of procedure that has characterized natural science since the 17th century, consisting in systematic observation, measurement, and experiment, and the formulation, testing, and modification of hypotheses.

Back 47

1. Scientific Method (26)

Front 48

The foundation for understanding the reproduction and growth of all organisms. The ideas that all living matter consists of cells, cells are the structural and functional units of life, and all cells come from preexisting cells.

Back 48

1. Cell Theory (28)

Front 49

The basic storage vehicle or central plan of heredity information. It is stored as a sequence of nucleotides in a linear nucleotide polymer. Two of the polymers wind around each other like the outside and inside rails of a circular staircase.

Back 49

1. DNA (Deoxyribonucleic Acid) (28)

Front 50

One of the basic principles of biology. The main concept of this theory is that traits are passed from parents to offspring through ____ transmission. _____ are located on chromosomes and consist of DNA.

Back 50

1. Gene Theory (28)

Front 51

The genetic information of an organism.

Back 51

1. Genome (28)

Front 52

The genes of an organism are inherited as discrete units.

Back 52

1. Theory of Heredity (30)

Front 53

The genes of Mendel’s theory are physically located on chromosomes and that it is because chromosomes are parceled out in a regular manner during reproduction that Mendel’s regular patterns are seen.

Back 53

1. Chromosomal Theory of Inheritance (30)

Front 54

Advanced by Charles Darwin in 1859, attributes the diversity of the living world to natural selection.

Back 54

1. Theory of Evolution (30)

Front 55

1. Biology and the Living World: Biology – the study of ______ things.

Back 55

Biology and the Living World: Biology – the study of [LIVING] things.

Front 56

1. Biology and the Living World: Living things are _______.

Back 56

Biology and the Living World: Living things are [DIVERSE].

Front 57

1. Biology and the Living World: There are enough ____________ among some living things that they can be grouped into the same _______.

Back 57

Biology and the Living World: There are enough [SIMILARITIES] among some living things that they can be grouped into the same [KINGDOM].

Front 58

1. Biology and the Living World: Members of different ________ are usually very different from each other.

Back 58

Biology and the Living World: Members of different [KINGDOMS] are usually very different from each other.

Front 59

1. The Six Kingdoms of Life: This kingdom of prokaryotes (the simplest of cells that do not have ______) includes this methanogen, which manufactures methane as a result of its metabolic activity. (_______)

Back 59

The Six Kingdoms of Life: This kingdom of prokaryotes (the simplest of cells that do not have [NUCLEI]) includes this methanogen, which manufactures methane as a result of its metabolic activity. ([ARCHAEA])

Front 60

1. The Six Kingdoms of Life: This group is the second of the two prokaryotic kingdoms. Shown here are purple sulfur bacteria, which are able to convert light energy into ________ energy. (________)

Back 60

The Six Kingdoms of Life: This group is the second of the two prokaryotic kingdoms. Shown here are purple sulfur bacteria, which are able to convert light energy into [CHEMICAL] energy. (BACTERIA)

Front 61

1. The Six Kingdoms of Life: Most of the unicellular eukaryotes (those whose cells contain a _______) are grouped into this kingdom, and so are the multicellular algae pictured here. (________)

Back 61

The Six Kingdoms of Life: Most of the unicellular eukaryotes (those whose cells contain a [NUCLEUS]) are grouped into this kingdom, and so are the multicellular algae pictured here. ([PROTISTA])

Front 62

1. The Six Kingdoms of Life: This kingdom contains nonphotosynthetic organisms, mostly multicellular, that digest their food __________, such as these mushrooms. (_____)

Back 62

The Six Kingdoms of Life: This kingdom contains nonphotosynthetic organisms, mostly multicellular, that digest their food [EXTERNALLY], such as these mushrooms. ([FUNGI])

Front 63

1. The Six Kingdoms of Life: This kingdom contains photosynthetic multicellular organisms that are ___________, such as the flower plant pictured here. (_______)

Back 63

The Six Kingdoms of Life: This kingdom contains photosynthetic multicellular organisms that are [TERRESTRIAL], such as the flower plant pictured here. ([PLANTAE])

Front 64

1. The Six Kingdoms of Life: Organisms in this kingdom are nonphotosynthetic multicellular organisms that digest their food __________, such as this ram. (________)

Back 64

The Six Kingdoms of Life: Organisms in this kingdom are nonphotosynthetic multicellular organisms that digest their food [INTERNALLY], such as this ram. ([ANIMALIA])

Front 65

1. Cellular organization – composed of ___ or ____ cells.

Back 65

Cellular organization – composed of [ONE] or [MORE] cells.

Front 66

1. Metabolism – use of ______ to power processes.

Back 66

Metabolism – use of [ENERGY] to power processes.

Front 67

1. Homeostasis – maintain stable ________ conditions so that their complex _________ can be better coordinated.

Back 67

Homeostasis – maintain stable [INTERNAL] conditions so that their complex [PROCESSES] can be better coordinated.

Front 68

1. Growth and Reproduction – able to ____ and _________.

Back 68

Growth and Reproduction – able to [GROW] and [REPRODUCE].

Front 69

1. Heredity – genetic system that is based on the ___________ and ___________ of DNA.

Back 69

Heredity – genetic system that is based on the [REPLICATION] and [DUPLICATION] of DNA.

Front 70

1. Is it alive? Escherichia coli bacteria (e.coli)

Back 70

Is it alive? Escherichia coli bacteria (e.coli)

Front 71

1. Is it alive? Rocks? Moss?

Back 71

Is it alive? Rocks? Moss?

Front 72

1. Is it alive? Robot?

Back 72

Is it alive? Robot?

Front 73

1. Is it alive? Ocean life?

Back 73

Is it alive? Ocean life?

Front 74

1. Is it alive? Firn?

Back 74

Is it alive? Firn?

Front 75

1. Is it alive? Clam?

Back 75

Is it alive? Clam?

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Front 80

1. Biological Themes: Evolution – _______ change in a species over ____.

Back 80

Biological Themes: Evolution – [GENETIC] change in a species over [TIME].

Front 81

1. Biological Themes: Flow of Energy – from ___ to plants to plant eating _______, etc.

Back 81

Biological Themes: Flow of Energy – from [SUN] to plants to plant eating [ANIMALS], etc.

Front 82

1. Biological Themes: Cooperation – between 2 _________.

Back 82

Biological Themes: Cooperation – between 2 [ORGANISMS].

Front 83

1. Biological Themes: Structure Determines Function – the way something is __________ allows for a specific function(s).

Back 83

Biological Themes: Structure Determines Function – the way something is [STRUCTURED] allows for a specific function(s).

Front 84

1. Biological Themes: Homeostasis – relatively ______ internal environment.

Back 84

Biological Themes: Homeostasis – relatively [STABLE] internal environment.

Front 85

Back 85

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Front 90

1. How Scientists Think: Deductive Reasoning – make individual decisions by applying a “_____” of accepted general principles.

Back 90

How Scientists Think: Deductive Reasoning – make individual decisions by applying a “[GUIDE]” of accepted general principles.

Front 91

1. How Scientists Think: Inductive Reasoning – discovering general principles by careful ___________.

Back 91

How Scientists Think: Inductive Reasoning – discovering general principles by careful [EXAMINATION].

Front 92

1. How Scientists Think: What Kind of Reasoning? I left for my first day of class 20 minutes before it started and got there on time. I should leave 20 minutes before class every day to get there on time.

Back 92

Inductive Reasoning, forming a general principle (or hypothesis) that it takes 20 minutes to get to class on time.

Front 93

1. How Scientists Think: What Kind of Reasoning? Every day I leave 20 minutes before class and arrive on time.

Back 93

Deductive Reasoning, based on the general principle that it will take the same amount of time to get to school every day if traffic and road conditions are normal.

Front 94

1. Science in Action: Scientist Joseph ______ observed in 1985 that ozone levels in Antarctica were alarmingly low (30% drop since 1980) – Pollution by chlorofluorocarbons (CFCs) was later found to be the culprit – CFCs were common components of many _________ products, such as: coolants used in air conditioners, propellants in aerosols, and foaming agents in Styrofoam.

Back 94

Science in Action: Scientist Joseph [FARMAN] observed in 1985 that ozone levels in Antarctica were alarmingly low (30% drop since 1980) – Pollution by chlorofluorocarbons (CFCs) was later found to be the culprit – CFCs were common components of many [SYNTHETIC] products, such as: coolants used in air conditioners, propellants in aerosols, and foaming agents in Styrofoam.

Front 95

1. Science in Action: Ozone depletion is a serious matter: ozone acts as a sunscreen against ___________ rays from the sun, and a 1% drop in ozone leads to a _% increase in skin cancer. A world-wide reduction in CFC production has helped alleviate ozone depletion.

Back 95

Science in Action: Ozone depletion is a serious matter: ozone acts as a sunscreen against [ULTRAVIOLET] rays from the sun, and a 1% drop in ozone leads to a [6]% increase in skin cancer. A world-wide reduction in CFC production has helped alleviate ozone depletion.

Front 96

1. Theories Unify Biology as a Science: Cell Theory: Organization of Life – 1839 Matthias _________ and Theodor Schwann concluded that all living organisms consist of _____.

Back 96

Theories Unify Biology as a Science: Cell Theory: Organization of Life – 1839 Matthias [SCHLEIDEN] and Theodor Schwann concluded that all living organisms consist of [CELLS].

Front 97

1. Theories Unify Biology as a Science: Gene Theory: Molecular Basis of Inheritance – ________ and RNA molecules are encoded by an organisms’ _____ (portions of DNA) that determine what an organism is like.

Back 97

Theories Unify Biology as a Science: Gene Theory: Molecular Basis of Inheritance – [PROTEINS] and RNA molecules are encoded by an organisms’ [GENES] (portions of DNA) that determine what an organism is like.

Front 98

1. Theories Unify Biology as a Science: Theory of Heredity: Unity of Life – 1865 Gregor ______ stated that genes of an organism are _________ as discrete units.

Back 98

Theories Unify Biology as a Science: Theory of Heredity: Unity of Life – 1865 Gregor [MENDEL] stated that genes of an organism are [INHERITED] as discrete units.

Front 99

1. Theories Unify Biology as a Science: Theory of Evolution: Diversity of Life – 1859 Charles ______ attributed the diversity of the living world to _______ _________.

Back 99

Theories Unify Biology as a Science: Theory of Evolution: Diversity of Life – 1859 Charles [DARWIN] attributed the diversity of the living world to [NATURAL SELECTION].

Front 100

1. Theories Unify Biology as a Science: Theory of Evolution: Diversity of Life – Natural Selection – the differential ____________ of genotypes caused by factors in the environment. Leads to ____________ change.

Back 100

Theories Unify Biology as a Science: Theory of Evolution: Diversity of Life – Natural Selection – the differential [REPRODUCTION] of genotypes caused by factors in the environment. Leads to [EVOLUTIONARY] change.

Front 101

Back 101

Front 102

1. How do we know what we know? Scientists try to establish what is true by investigating in ______. Form general __________ through inductive and deductive reasoning. Remember Joseph Farman and CFCs?

Back 102

How do we know what we know? Scientists try to establish what is true by investigating in [STAGES]. Form general [PRINCIPLES] through inductive and deductive reasoning. Remember Joseph Farman and CFCs?

Front 103

1. How do we know what we know? Joseph Farman followed a process called the __________ ______. He investigated what he thought was a “true general _________” using the scientific method stages: Observation, Hypothesis, Predictions, Testing, Controls, and Conclusion.

Back 103

How do we know what we know? Joseph Farman followed a process called the [SCIENTIFIC METHOD]. He investigated what he thought was a “true general [PRINCIPLE]” using the scientific method stages: Observation, Hypothesis, Predictions, Testing, Controls, and Conclusion.

Front 104

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Front 105

1. Biology is the study of ______ things – the science of life. (16)

Back 105

Biology is the study of [LIVING] things – the science of life. (16)

Front 106

1. The living world is full of a variety of creatures – whales, butterflies, mushrooms, and mosquitoes – all of which can be categorized into six groups, or kingdoms, of organisms: _______, ________, ________, _____, _______, and ________. (16)

Back 106

The living world is full of a variety of creatures – whales, butterflies, mushrooms, and mosquitoes – all of which can be categorized into six groups, or kingdoms, of organisms: [ARCHAEA], [BACTERIA], [PROTISTA], [FUNGI], [PLANTAE], and [ANIMALIA]. (16)

Front 107

1. All ______ ______ have much in common. (16)

Back 107

All [LIVING THINGS] have much in common. (16)

Front 108

1. Archaea. This kingdom of prokaryotes (the simplest of cells that do not have ______) includes this methanogen, which manufactures methane as a result of its metabolic activity. (16)

Back 108

Archaea. This kingdom of prokaryotes (the simplest of cells that do not have [NUCLEI]) includes this methanogen, which manufactures methane as a result of its metabolic activity. (16)

Front 109

1. Bacteria. This group is the second of the two ___________ kingdoms. Shown here are purple sulfur bacteria, which are able to convert light energy into chemical energy. (16)

Back 109

Bacteria. This group is the second of the two [PROKARYOTIC] kingdoms. Shown here are purple sulfur bacteria, which are able to convert light energy into chemical energy. (16)

Front 110

1. Protista. Most of the unicellular eukaryotes (those whose cells contain a _______) are grouped into this kingdom, and so are the multicellular algae pictured here. (16)

Back 110

Protista. Most of the unicellular eukaryotes (those whose cells contain a [NUCLEUS]) are grouped into this kingdom, and so are the multicellular algae pictured here. (16)

Front 111

1. Fungi. This kingdom contains _________________ organisms, mostly multicellular, that digest their food externally, such as these mushrooms. (16)

Back 111

Fungi. This kingdom contains [NONPHOTOSYNTHETIC] organisms, mostly multicellular, that digest their food externally, such as these mushrooms. (16)

Front 112

1. Plantae. This kingdom contains photosynthetic _____________ organisms that are terrestrial, such as the flowering plant pictured here. (16)

Back 112

Plantae. This kingdom contains photosynthetic [MULTICELLULAR] organisms that are terrestrial, such as the flowering plant pictured here. (16)

Front 113

1. Animalia. Organisms in this kingdom are _________________ multicellular organisms that digest their food internally, such as this ram. (16)

Back 113

Animalia. Organisms in this kingdom are [NONPHOTOSYNTHETIC] multicellular organisms that digest their food internally, such as this ram. (16)

Front 114

1. Key Learning Outcome 1.1 – The ______ _____ is very diverse, but all things share many key properties. (16)

Back 114

Key Learning Outcome 1.1 – The [LIVING WORLD] is very diverse, but all things share many key properties. (16)

Front 115

1. Figure 1.1 – The six kingdoms of life. Biologists assign all living things to six major categories called ________. Each kingdom is profoundly different from the others. (16)

Back 115

Figure 1.1 – The six kingdoms of life. Biologists assign all living things to six major categories called [KINGDOMS]. Each kingdom is profoundly different from the others. (16)

Front 116

1. All living things share five basic properties, passed down over millions of years from the first organisms to evolve on earth: ________ ____________, __________, ___________, ______ ___ ____________, and ________. (17)

Back 116

All living things share five basic properties, passed down over millions of years from the first organisms to evolve on earth: [CELLULAR ORGANIZATION], [METABOLISM], [HOMEOSTASIS], [GROWTH] and [REPRODUCTION], and [HEREDITY]. (17)

Front 117

1. Cellular Organization (a). All living things are composed of one or more _____. (17)

Back 117

Cellular Organization (a). All living things are composed of one or more [CELLS]. (17)

Front 118

1. Cellular Organization (b). A cell is a tiny compartment with a thin covering called a ________. (17)

Back 118

Cellular Organization (b). A cell is a tiny compartment with a thin covering called a [MEMBRANE]. (17)

Front 119

1. Cellular Organization (c). Some cells have simple _________, while others are complexly organized, but all are able to grow and reproduce. (17)

Back 119

Cellular Organization (c). Some cells have simple [INTERIORS], while others are complexly organized, but all are able to grow and reproduce. (17)

Front 120

1. Cellular Organization (d). Many _________ possess only a single cell, like the paramecia in figure 1.2; your body contains from 10 trillion to 100 trillion cells (depending on how big you are). (17)

Back 120

Cellular Organization (d). Many [ORGANISMS] possess only a single cell, like the paramecia in figure 1.2; your body contains from 10 trillion to 100 trillion cells (depending on how big you are). (17)

Front 121

1. Metabolism (a). All living things use energy. Moving, growing, thinking – everything you do requires energy. Where does all this energy come from? (17)

Back 121

It is captured from sunlight by plants and algae through photosynthesis. (17)

Front 122

1. Metabolism (b). To get the energy that powers our lives we extract it from ______ or from plant-eating _______. That’s what the kingfisher is doing in figure 1.3, eating a fish that ate algae. (17)

Back 122

Metabolism (b). To get the energy that powers our lives we extract it from [PLANTS] or from plant-eating [ANIMALS]. That’s what the kingfisher is doing in figure 1.3, eating a fish that ate algae. (17)

Front 123

1. Metabolism (c). The transfer of energy from one form to another in _____ is an example of metabolism. (17)

Back 123

Metabolism (c). The transfer of energy from one form to another in [CELLS] is an example of metabolism. (17)

Front 124

1. Metabolism (d). All organisms require energy to grow, and all organisms transfer this energy from one place to another within cells using special energy-carrying molecules called ___ molecules. (17)

Back 124

Metabolism (d). All organisms require energy to grow, and all organisms transfer this energy from one place to another within cells using special energy-carrying molecules called [ATP] molecules. (17)

Front 125

1. Homeostasis (a). All living things maintain stable ________ conditions so that their complex processes can be better coordinated. (17)

Back 125

Homeostasis (a). All living things maintain stable [INTERNAL] conditions so that their complex processes can be better coordinated. (17)

Front 126

1. Homeostasis (b). While the environment often varies a lot, organisms act to keep their interior conditions relatively constant; a process called ___________. (17)

Back 126

Homeostasis (b). While the environment often varies a lot, organisms act to keep their interior conditions relatively constant; a process called [HOMEOSTASIS]. (17)

Front 127

1. Homeostasis (c). Your body acts to maintain an ________ ___________ of 37˚C (98.6˚F), however hot or cold the weather might be. (17)

Back 127

Homeostasis (c). Your body acts to maintain an [INTERNAL TEMPERATURE] of 37˚C (98.6˚F), however hot or cold the weather might be. (17)

Front 128

1. Growth and reproduction (a). All living things grow and reproduce. ________ increase in size and simply split in two as often as every 15 minutes, while more complex _________ grow by increasing the number of cells and reproduce sexually (some, like the bristlecone pine of California, have reproduced after 4,600 years). (17)

Back 128

Growth and reproduction (a). All living things grow and reproduce. [BACTERIA] increase in size and simply split in two as often as every 15 minutes, while more complex [ORGANISMS] grow by increasing the number of cells and reproduce sexually (some, like the bristlecone pine of California, have reproduced after 4,600 years). (17)

Front 129

1. Heredity. All organisms possess a genetic system that is based on the replication and ___________ of a long molecule called DNA (deoxyribonucleic acid). (17)

Back 129

Heredity. All organisms possess a genetic system that is based on the replication and [DUPLICATION] of a long molecule called DNA (deoxyribonucleic acid). (17)

Front 130

1. The information that determines what an individual organism will be like is contained in a code that is dictated by the order of the subunits making up the ___ molecule, just as the order of letters on this page determines the sense of what you are reading. (17)

Back 130

The information that determines what an individual organism will be like is contained in a code that is dictated by the order of the subunits making up the [DNA] molecule, just as the order of letters on this page determines the sense of what you are reading. (17)

Front 131

1. Each set of instructions within the DNA is called a ____. (17)

Back 131

Each set of instructions within the DNA is called a [GENE]. (17)

Front 132

1. Together, the genes determine what the organism will be like. Because DNA is faithfully copied from one generation to the next, any change in a gene is also preserved and passed on to ______ ___________. (17)

Back 132

Together, the genes determine what the organism will be like. Because DNA is faithfully copied from one generation to the next, any change in a gene is also preserved and passed on to [FUTURE GENERATIONS]. (17)

Front 133

1. The transmission of characteristics from parent to offspring is a process called ________. (17)

Back 133

The transmission of characteristics from parent to offspring is a process called [HEREDITY]. (17)

Front 134

1. Learning Objective 1.2.1 – List the five basic properties shared by all living things: ________ ____________, metabolism, ___________, growth and reproduction, and ________. (17)

Back 134

Learning Objective 1.2.1 – List the five basic properties shared by all living things: [CELLULAR ORGANIZATION], metabolism, [HOMEOSTASIS], growth and reproduction, and [HEREDITY]. (17)

Front 135

1. Figure 1.2 – Cellular organization. These paramecia are complex single-celled protists that have just ingested several yeast cells. Like these paramecia, many _________ consist of just a single cell, while others are composed of trillions of cells. (17)

Back 135

Figure 1.2 – Cellular organization. These paramecia are complex single-celled protists that have just ingested several yeast cells. Like these paramecia, many [ORGANISMS] consist of just a single cell, while others are composed of trillions of cells. (17)

Front 136

1. Figure 1.3 – Metabolism. This kingfisher obtains the energy it needs to move, grow, and carry out its body processes by eating fish. It metabolizes this food using ________ processes that occur within cells. (17)

Back 136

Figure 1.3 – Metabolism. This kingfisher obtains the energy it needs to move, grow, and carry out its body processes by eating fish. It metabolizes this food using [CHEMICAL] processes that occur within cells. (17)

Front 137

1. Key Learning Outcome 1.2 – All ______ ______ possess cells that carry out metabolism, maintain stable internal conditions, reproduce themselves, and use DNA to transmit hereditary information to offspring. (17)

Back 137

Key Learning Outcome 1.2 – All [LIVING THINGS] possess cells that carry out metabolism, maintain stable internal conditions, reproduce themselves, and use DNA to transmit hereditary information to offspring. (17)

Front 138

1. Learning Objective 1.3.1 – List the 13 hierarchal levels of the organization of life: _____, _________, ______________, __________, _____, _______, ______, _____ _______, ________, __________, _______, _________, and _________. (18)

Back 138

Learning Objective 1.3.1 – List the 13 hierarchal levels of the organization of life: [ATOMS], [MOLECULES], [MACROMOLECULES], [ORGANELLES], [CELLS], [TISSUES], [ORGANS], [ORGAN SYSTEMS], [ORGANISM], [POPULATION], [SPECIES], [COMMUNITY], and [ECOSYSTEM]. (18)

Front 139

1. The complexity of life is categorized in three levels: ________, __________, and ____________. (18)

Back 139

The complexity of life is categorized in three levels: [CELLULAR], [ORGANISMAL], and [POPULATIONAL]. (18)

Front 140

1. The complexity of life is categorized in three levels: cellular (_____, _________, ______________, __________, and _____). (18)

Back 140

The complexity of life is categorized in three levels: cellular ([ATOMS], [MOLECULES], [MACROMOLECULES], [ORGANELLES], and [CELLS]). (18)

Front 141

1. The complexity of life is categorized in three levels: organismal (_______, ______, _____ _______, and ________). (18)

Back 141

The complexity of life is categorized in three levels: organismal ([TISSUES], [ORGANS], [ORGAN SYSTEMS], and [ORGANISM]). (18)

Front 142

1. The complexity of life is categorized in three levels: populational (__________, _______, _________, and _________). (18)

Back 142

The complexity of life is categorized in three levels: populational ([POPULATION], [SPECIES], [COMMUNITY], and [ECOSYSTEM]). (18)

Front 143

1. Cellular Level. Following down the first section of figure 1.4, you can see that structures get more and more complex – that there is a _________ of increasing complexity within cells. (18)

Back 143

Cellular Level. Following down the first section of figure 1.4, you can see that structures get more and more complex – that there is a [HIERARCHY] of increasing complexity within cells. (18)

Front 144

1. Cellular Level: Atoms. The fundamental elements of ______ are atoms. (18)

Back 144

Cellular Level: Atoms. The fundamental elements of [MATTER] are atoms. (18)

Front 145

1. Cellular Level: Molecules. Atoms are joined together into complex clusters called _________. (18)

Back 145

Cellular Level: Molecules. Atoms are joined together into complex clusters called [MOLECULES]. (18)

Front 146

1. Cellular Level: Macromolecules. Large _______ molecules are called macromolecules. DNA, which stores the hereditary information in all living _________, is a macromolecule. (18)

Back 146

Cellular Level: Macromolecules. Large [COMPLEX] molecules are called macromolecules. DNA, which stores the hereditary information in all living [ORGANISMS], is a macromolecule. (18)

Front 147

1. Cellular Level: Organelles. Complex biological molecules are assembled into tiny ____________ within cells called organelles, within which cellular activities are organized. (18)

Back 147

Cellular Level: Organelles. Complex biological molecules are assembled into tiny [COMPARTMENTS] within cells called organelles, within which cellular activities are organized. (18)

Front 148

1. The _______ is an organelle within which the cell’s DNA is stored. (18)

Back 148

The [NUCLEUS] is an organelle within which the cell’s DNA is stored. (18)

Front 149

1. Cellular Level: Cells. Organelles and other ________ are assembled in the membrane-bounded units we call cells. Cells are the ________ level of organization that can be considered alive. (18)

Back 149

Cellular Level: Cells. Organelles and other [ELEMENTS] are assembled in the membrane-bounded units we call cells. Cells are the [SMALLEST] level of organization that can be considered alive. (18)

Front 150

1. Organismal Level. At the organismal level, in the second section of figure 1.4, _____ are organized into four levels of complexity. (18)

Back 150

Organismal Level. At the organismal level, in the second section of figure 1.4, [CELLS] are organized into four levels of complexity. (18)

Front 151

1. Organismal Level: Tissues. The most basic level is that of _______, which are groups of similar cells that act as a functional unit. (18)

Back 151

Organismal Level: Tissues. The most basic level is that of [TISSUES], which are groups of similar cells that act as a functional unit. (18)

Front 152

1. Nerve tissue is one kind of tissue, composed of cells called _______ that are specialized to carry electrical signals from one place to another in the body. (19)

Back 152

Nerve tissue is one kind of tissue, composed of cells called [NEURONS] that are specialized to carry electrical signals from one place to another in the body. (19)

Front 153

1. Figure 1.4 – Levels of organization. A traditional and very useful method of sorting through the many ways in which the organisms of the living world ________ is to arrange them in terms of levels of organization, proceeding from the very small and simple to the very large and complex. Here we examine organization within the cellular, organismal, and populational levels. (18)

Back 153

Figure 1.4 – Levels of organization. A traditional and very useful method of sorting through the many ways in which the organisms of the living world [INTERACT] is to arrange them in terms of levels of organization, proceeding from the very small and simple to the very large and complex. Here we examine organization within the cellular, organismal, and populational levels. (18)

Front 154

1. Organismal Level: Organs. Tissues, in turn, are grouped into organs, which are body structures composed of several different tissues grouped together in a __________ and __________ unit. (19)

Back 154

Organismal Level: Organs. Tissues, in turn, are grouped into organs, which are body structures composed of several different tissues grouped together in a [STRUCTURAL] and [FUNCTIONAL] unit. (19)

Front 155

1. Your brain is an organ composed of _____ _____ and a variety of connective tissues that form protective coverings and distribute _____. (19)

Back 155

Your brain is an organ composed of [NERVE CELLS] and a variety of connective tissues that form protective coverings and distribute [BLOOD]. (19)

Front 156

1. Organismal Level: Organ Systems. At the third level of organization, organs are _______ into organ systems. The nervous system, for example, consists of sensory organs, the brain and spinal cord, neurons that convey signals to and from them, and supporting cells. (19)

Back 156

Organismal Level: Organ Systems. At the third level of organization, organs are [GROUPED] into organ systems. The nervous system, for example, consists of sensory organs, the brain and spinal cord, neurons that convey signals to and from them, and supporting cells. (19)

Front 157

1. Organismal Level: Organism. Separate _____ _______ function together to form an organism. (19)

Back 157

Organismal Level: Organism. Separate [ORGAN SYSTEMS] function together to form an organism. (19)

Front 158

1. Populational Level. Organisms are further organized into several ____________ levels within the living world, as you can see in the third section of figure 1.4. (19)

Back 158

Populational Level. Organisms are further organized into several [HIERARCHICAL] levels within the living world, as you can see in the third section of figure 1.4. (19)

Front 159

1. Populational Level: Population. The most basic of these is the population, which is a group of organisms of the ____ _______ living in the same place. A flock of geese living together on a pond is a population. (19)

Back 159

Populational Level: Population. The most basic of these is the population, which is a group of organisms of the [SAME SPECIES] living in the same place. A flock of geese living together on a pond is a population. (19)

Front 160

1. Populational Level: Species. All the populations of a particular kind of ________ together form a species, its members similar in appearance and able to __________. All Canada geese, whether found in Canada, Minnesota, or Missouri, are basically the same, members of the species Branta Canadensis. Sandhill cranes are a different species. (19)

Back 160

Populational Level: Species. All the populations of a particular kind of [ORGANISM] together form a species, its members similar in appearance and able to [INTERBREED]. All Canada geese, whether found in Canada, Minnesota, or Missouri, are basically the same, members of the species Branta Canadensis. Sandhill cranes are a different species. (19)

Front 161

1. Populational Level: Community. At a higher level of biological organization, a community consists of all the populations of _________ species living ________ in one place. Geese, for example, may share their pond with ducks, fish, grasses, and many kinds of insects. All interact in a single pond community. (19)

Back 161

Populational Level: Community. At a higher level of biological organization, a community consists of all the populations of [DIFFERENT] species living [TOGETHER] in one place. Geese, for example, may share their pond with ducks, fish, grasses, and many kinds of insects. All interact in a single pond community. (19)

Front 162

1. Populational Level: Ecosystem. At the highest tier of biological organization, a biological _________ and the soil and water within which it lives together constitute an ecological system, or ecosystem. (19)

Back 162

Populational Level: Ecosystem. At the highest tier of biological organization, a biological [COMMUNITY] and the soil and water within which it lives together constitute an ecological system, or ecosystem. (19)

Front 163

1. At each higher level in the living hierarchy, novel properties emerge that were not present at the simpler level of organization. These ________ __________ result from the way in which components interact and often cannot be guessed just by looking at the parts themselves. (19)

Back 163

At each higher level in the living hierarchy, novel properties emerge that were not present at the simpler level of organization. These [EMERGENT PROPERTIES] result from the way in which components interact and often cannot be guessed just by looking at the parts themselves. (19)

Front 164

1. The emergent properties of life are the natural consequence of the hierarchy, or __________ ____________, that is the hallmark of life. Functional properties emerge from more complex organization. (19)

Back 164

The emergent properties of life are the natural consequence of the hierarchy, or [STRUCTURAL ORGANIZATION], that is the hallmark of life. Functional properties emerge from more complex organization. (19)

Front 165

1. __________ is an emergent property of life. The chemical reactions within a cell arise from interactions between molecules that are orchestrated by the orderly environment of the cell’s ________. (19)

Back 165

[METABOLISM] is an emergent property of life. The chemical reactions within a cell arise from interactions between molecules that are orchestrated by the orderly environment of the cell’s [INTERIOR]. (19)

Front 166

1. Consciousness is an emergent property of the brain that results from the interactions of many _______ in different parts of the brain. (19)

Back 166

Consciousness is an emergent property of the brain that results from the interactions of many [NEURONS] in different parts of the brain. (19)

Front 167

1. Key Learning Outcome 1.3 – Cells, multicellular organisms, and ecological systems each are organized in a hierarchy or increased __________. Life’s hierarchal organization is responsible for the ________ __________ that characterize so many aspects of the living world. (19)

Back 167

Key Learning Outcome 1.3 – Cells, multicellular organisms, and ecological systems each are organized in a hierarchy or increased [COMPLEXITY]. Life’s hierarchal organization is responsible for the [EMERGENT PROPERTIES] that characterize so many aspects of the living world. (19)

Front 168

1. Learning Objective 1.4.1 – List the five general themes that unify biology as a science: _________, ___ ___ __ ______, ___________, _________ __________ ________, and ___________. (20)

Back 168

Learning Objective 1.4.1 – List the five general themes that unify biology as a science: [EVOLUTION], [THE FLOW OF ENERGY], [COOPERATION], [STRUCTURE DETERMINES FUNCTION], and [HOMEOSTASIS]. (20)

Front 169

1. Evolution is _______ change in a species over time. (20)

Back 169

Evolution is [GENETIC] change in a species over time. (20)

Front 170

1. Charles Darwin was an English naturalist who, in 1859, proposed the idea that this change is a result of a process called _______ _________. Simply stated, those organisms whose characteristics make them better able to survive the challenges of their environment live to _________, passing their favorable characteristics on to their offspring. (20)

Back 170

Charles Darwin was an English naturalist who, in 1859, proposed the idea that this change is a result of a process called [NATURAL SELECTION]. Simply stated, those organisms whose characteristics make them better able to survive the challenges of their environment live to [REPRODUCE], passing their favorable characteristics on to their offspring. (20)

Front 171

1. Darwin was thoroughly familiar with variation in domesticated animals (in addition to many nondomesticated organisms), and he knew that varieties of pigeons could be selected by breeders to exhibit exaggerated characteristics, a process called __________ _________. (20)

Back 171

Darwin was thoroughly familiar with variation in domesticated animals (in addition to many nondomesticated organisms), and he knew that varieties of pigeons could be selected by breeders to exhibit exaggerated characteristics, a process called [ARTIFICIAL SELECTION]. (20)

Front 172

1. All organisms require ______ to carry out the activities of living – to build bodies and do work and think thoughts. (20)

Back 172

All organisms require [ENERGY] to carry out the activities of living – to build bodies and do work and think thoughts. (20)

Front 173

1. All of the ______ used by most organisms comes from the sun and is passed in one direction through __________. (20)

Back 173

All of the [ENERGY] used by most organisms comes from the sun and is passed in one direction through [ECOSYSTEMS]. (20)

Front 174

1. The simplest way to understand the ____ of energy trough the living world is to look at who uses it. (20)

Back 174

The simplest way to understand the [FLOW] of energy trough the living world is to look at who uses it. (20)

Front 175

1. The first stage of energy’s journey is its capture by green plants, algae, and some bacteria by the process of ______________. This process uses energy from the sun to synthesize sugars that photosynthetic organisms like plants store in their bodies. Plants then serve as a source of ____-_______ energy for animals that eat them. Other animals, like the eagle in table 1.1, may then eat the plant eaters. (20)

Back 175

The first stage of energy’s journey is its capture by green plants, algae, and some bacteria by the process of [PHOTOSYNTHESIS]. This process uses energy from the sun to synthesize sugars that photosynthetic organisms like plants store in their bodies. Plants then serve as a source of [LIFE-DRIVING] energy for animals that eat them. Other animals, like the eagle in table 1.1, may then eat the plant eaters. (20)

Front 176

1. At each stage, some energy is used for the processes of living, some is transferred, and much is lost, primarily as ____. (20)

Back 176

At each stage, some energy is used for the processes of living, some is transferred, and much is lost, primarily as [HEAT]. (20)

Front 177

1. The flow of energy is a key factor in shaping __________, affecting how many and what kinds of animals live in a community. (20)

Back 177

The flow of energy is a key factor in shaping [ECOSYSTEMS], affecting how many and what kinds of animals live in a community. (20)

Front 178

1. Organisms of two different species that live in direct contact, like the ants and the plant on which they live (table 1.1), form a type of relationship called _________. (20)

Back 178

Organisms of two different species that live in direct contact, like the ants and the plant on which they live (table 1.1), form a type of relationship called [SYMBIOSIS]. (20)

Front 179

1. ______ _____ possess organelles that are the descendants of symbiotic bacteria, and symbiotic fungi helped plants first invade land from the sea. (20)

Back 179

[ANIMAL CELLS] possess organelles that are the descendants of symbiotic bacteria, and symbiotic fungi helped plants first invade land from the sea. (20)

Front 180

1. The coevolution of flowering plants and insects – where changes in flowers influenced insect evolution and, in turn, changes in insects influenced flower evolution – has been responsible for much of life’s great _________. (20)

Back 180

The coevolution of flowering plants and insects – where changes in flowers influenced insect evolution and, in turn, changes in insects influenced flower evolution – has been responsible for much of life’s great [DIVERSITY]. (20)

Front 181

1. One of the most obvious lessons of biology is that biological structures are very well suited to their functions. You will see this at every level of organization: Within cells, the shapes of the proteins called _______ that cells use to carry out ________ reactions are precisely suited to match the chemicals the enzymes must manipulate. (20)

Back 181

One of the most obvious lessons of biology is that biological structures are very well suited to their functions. You will see this at every level of organization: Within cells, the shapes of the proteins called [ENZYMES] that cells use to carry out [CHEMICAL] reactions are precisely suited to match the chemicals the enzymes must manipulate. (20)

Front 182

1. Within the many kinds of organisms in the living world, body structures seem carefully ________ to carry out their functions – the long tongue with which the moth in table 1.1 sucks nectar from deep within a flower is one example. (20)

Back 182

Within the many kinds of organisms in the living world, body structures seem carefully [DESIGNED] to carry out their functions – the long tongue with which the moth in table 1.1 sucks nectar from deep within a flower is one example. (20)

Front 183

1. The superb fit of structure to function in the living world is no accident. Life has existed on earth for over 2 billion years, a long time for _________ to favor changes that better suit organisms to meet the challenges of living. (20)

Back 183

The superb fit of structure to function in the living world is no accident. Life has existed on earth for over 2 billion years, a long time for [EVOLUTION] to favor changes that better suit organisms to meet the challenges of living. (20)

Front 184

1. The high degree of specialization we see among complex organisms is only possible because these organisms act to maintain a relatively ______ internal environment, a process called homeostasis. (20)

Back 184

The high degree of specialization we see among complex organisms is only possible because these organisms act to maintain a relatively [STABLE] internal environment, a process called homeostasis. (20)

Front 185

1. Maintaining homeostasis in a body as complex as your or the hippo’s in table 1.1 requires a great deal of _________ back and forth between cells. (20)

Back 185

Maintaining homeostasis in a body as complex as your or the hippo’s in table 1.1 requires a great deal of [SIGNALING] back and forth between cells. (20)

Front 186

1. Key Learning Outcome 1.4 – The five general themes of biology are (1) evolution, (2) ___ ____ __ ______, (3) cooperation, (4) _________ __________ ________, and (5) homeostasis. (20)

Back 186

Key Learning Outcome 1.4 – The five general themes of biology are (1) evolution, (2) [THE FLOW OF ENERGY], (3) cooperation, (4) [STRUCTURE DETERMINES FUNCTION], and (5) homeostasis. (20)

Front 187

1. Learning Objective 1.5.1 – Identify the form of reasoning used in mathematics and computer science: _________ _________. (21)

Back 187

Learning Objective 1.5.1 – Identify the form of reasoning used in mathematics and computer science: [DEDUCTIVE REASONING]. (21)

Front 188

1. Science is a process of _____________, using observation, experimentation, and reasoning. (21)

Back 188

Science is a process of [INVESTIGATION], using observation, experimentation, and reasoning. (21)

Front 189

1. Not all investigations are scientific. For example, when you want to know how to get to Chicago from St. Louis, you do not conduct a scientific investigation – instead, you look at a map to determine a route. In other investigations, you make individual decisions by applying a “guide” of accepted general principles (figure 1.5). This is called _________ _________. (21)

Back 189

Not all investigations are scientific. For example, when you want to know how to get to Chicago from St. Louis, you do not conduct a scientific investigation – instead, you look at a map to determine a route. In other investigations, you make individual decisions by applying a “guide” of accepted general principles (figure 1.5). This is called [DEDUCTIVE REASONING]. (21)

Front 190

1. _________ _________, using general principles to explain specific observations, is the reasoning of mathematics, philosophy, politics, and ethics; deductive reasoning is also the way a computer works. (21)

Back 190

[DEDUCTIVE REASONING], using general principles to explain specific observations, is the reasoning of mathematics, philosophy, politics, and ethics; deductive reasoning is also the way a computer works. (21)

Front 191

1. Some general principles are derived from observation of the physical world around us. Science is devoted to discovering the general principles that govern the _________ of the physical world. How do scientists discover such general principles: Scientists are, above all, observers: They look at the world to understand how it _____. (21)

Back 191

Some general principles are derived from observation of the physical world around us. Science is devoted to discovering the general principles that govern the [OPERATION] of the physical world. How do scientists discover such general principles: Scientists are, above all, observers: They look at the world to understand how it [WORKS]. (21)

Front 192

1. It is from observations that scientists determine the principles that govern our physical world. This way of discovering general principles by careful examination of specific cases is called _________ _________. (21)

Back 192

It is from observations that scientists determine the principles that govern our physical world. This way of discovering general principles by careful examination of specific cases is called [INDUCTIVE REASONING]. (21)

Front 193

1. Inductive reasoning first became popular about 400 years ago, when Isaac ______, Francis _____, and others began to conduct experiments and from the results infer general principles about how the world ________. (21)

Back 193

Inductive reasoning first became popular about 400 years ago, when Isaac [NEWTON], Francis [BACON], and others began to conduct experiments and from the results infer general principles about how the world [OPERATES]. (21)

Front 194

1. Key Learning Outcome 1.5 – Science uses inductive reasoning to infer general principles from detailed ___________. (21)

Back 194

Key Learning Outcome 1.5 – Science uses inductive reasoning to infer general principles from detailed [OBSERVATION]. (21)

Front 195

1. _________ _________ – An Accepted General Principle – When traffic lights along city streets are “timed” to change at the time interval it takes traffic to pass between them, the result will be a smooth flow of traffic. Traveling at the speed limit, you approach each intersection anticipating that the red light will turn green as you reach the intersection. (21)

Back 195

[DEDUCTIVE REASONING] – An Accepted General Principle – When traffic lights along city streets are “timed” to change at the time interval it takes traffic to pass between them, the result will be a smooth flow of traffic. Traveling at the speed limit, you approach each intersection anticipating that the red light will turn green as you reach the intersection. (21)

Front 196

1. _________ _________ – Observations of Specific Events – Driving down the street at the speed limit, you observe that the red traffic light turns green just as you approach the intersection. Maintaining the same speed, you observe the same event at the next several intersections: the traffic lights turn green just as you approach the intersections. When you speed up, however, the light doesn’t change until after you reach the intersection. Formation of a General Principle – You conclude that the traffic lights along this street are “timed” to change in the time it takes your car, traveling at the speed limit, to traverse the distance between them. (21)

Back 196

[INDUCTIVE REASONING] – Observations of Specific Events – Driving down the street at the speed limit, you observe that the red traffic light turns green just as you approach the intersection. Maintaining the same speed, you observe the same event at the next several intersections: the traffic lights turn green just as you approach the intersections. When you speed up, however, the light doesn’t change until after you reach the intersection. Formation of a General Principle – You conclude that the traffic lights along this street are “timed” to change in the time it takes your car, traveling at the speed limit, to traverse the distance between them. (21)

Front 197

1. Figure 1.5 – Deductive and Inductive Reasoning – A driver who assumes that the traffic signals are timed can use _________ reasoning to expect that the traffic lights will change predictably at intersections. In contrast, a driver who is not aware of the general control and programming of traffic signals can use _________ reasoning to determine that the traffic lights are timed as the driver encounters similar timing of signals at several intersections. (21)

Back 197

Figure 1.5 – Deductive and Inductive Reasoning – A driver who assumes that the traffic signals are timed can use [DEDUCTIVE] reasoning to expect that the traffic lights will change predictably at intersections. In contrast, a driver who is not aware of the general control and programming of traffic signals can use [INDUCTIVE] reasoning to determine that the traffic lights are timed as the driver encounters similar timing of signals at several intersections. (21)

Front 198

1. Figure 1.6 – How CFCs attack and destroy ozone – CFCs are stable chemicals that accumulate in the atmosphere as a by-product of industrial society (1). In the intense cold of the Antarctic, these CFCs adhere to tiny ice crystals in the upper atmosphere (2). UV light causes the breakdown of CFCs, producing chlorine (Cl). CL acts as a catalyst, converting O3 into O2 (3). As a result, more harmful __ _________ reaches the earth’s surface (4). (23)

Back 198

Figure 1.6 – How CFCs attack and destroy ozone – CFCs are stable chemicals that accumulate in the atmosphere as a by-product of industrial society (1). In the intense cold of the Antarctic, these CFCs adhere to tiny ice crystals in the upper atmosphere (2). UV light causes the breakdown of CFCs, producing chlorine (Cl). CL acts as a catalyst, converting O3 into O2 (3). As a result, more harmful [UV RADIATION] reaches the earth’s surface (4). (23)

Front 199

1. In 1985, Joseph ______, a British earth scientist working in Antarctica, discovered by analyzing the Antarctic sky, he found far less ozone (O3, a form of oxygen gas) than should be there – a __% drop from a reading recorded five years earlier in the Antarctic! Evidence soon mounted implicating synthetic chemicals as the culprit. (23)

Back 199

In 1985, Joseph [FARMAN], a British earth scientist working in Antarctica, discovered by analyzing the Antarctic sky, he found far less ozone (O3, a form of oxygen gas) than should be there – a [30]% drop from a reading recorded five years earlier in the Antarctic! Evidence soon mounted implicating synthetic chemicals as the culprit. (23)

Front 200

1. Detailed analysis of chemicals in the Antarctic atmosphere revealed a surprisingly high concentration of chlorine, a chemical known to destroy ozone. The source of the chlorine was a class of chemicals called ___________________ (____). (23)

Back 200

Detailed analysis of chemicals in the Antarctic atmosphere revealed a surprisingly high concentration of chlorine, a chemical known to destroy ozone. The source of the chlorine was a class of chemicals called [CHLOROFLUOROCARBONS (CFCs)]. (23)

Front 201

1. CFCs (the purple balls (1) in figure 1.6) have been manufactured in _____ _______ since they were invented in the 1920s, largely for use as coolants in air conditioners, propellants in aerosols, and foaming agents in making Styrofoam. (23)

Back 201

CFCs (the purple balls (1) in figure 1.6) have been manufactured in [LARGE AMOUNTS] since they were invented in the 1920s, largely for use as coolants in air conditioners, propellants in aerosols, and foaming agents in making Styrofoam. (23)

Front 202

1. CFCs were widely regarded as harmless because they are chemically unreactive under normal conditions. But in the atmosphere over Antarctica, CFCs condense onto tiny ___ ________ (2); in the spring, the CFCs break down and produce chlorine, which acts as a catalyst, attacking and destroying ozone, turning it into ______ ___ without the chlorine being used up (3). (23)

Back 202

CFCs were widely regarded as harmless because they are chemically unreactive under normal conditions. But in the atmosphere over Antarctica, CFCs condense onto tiny [ICE CRYSTALS] (2); in the spring, the CFCs break down and produce chlorine, which acts as a catalyst, attacking and destroying ozone, turning it into [OXYGEN GAS] without the chlorine being used up (3). (23)

Front 203

1. The thinning of the ozone layer in the upper atmosphere 25 to 40 kilometers above the surface of the earth is a serious matter. The ozone layer protects life from the harmful ___________ (UV) rays from the sun that bombard the earth continuously. (23)

Back 203

The thinning of the ozone layer in the upper atmosphere 25 to 40 kilometers above the surface of the earth is a serious matter. The ozone layer protects life from the harmful [ULTRAVIOLET (UV)] rays from the sun that bombard the earth continuously. (23)

Front 204

1. Like invisible sunglasses, the ozone layer filters out these dangerous rays. So when ozone is converted to oxygen gas, the UV rays are able to pass through to the earth (4). When UV rays damage the DNA in skin cells, it can lead to skin cancer. It is estimated that every _% drop in the atmospheric ozone concentration leads to a _% increase in skin cancers. (23)

Back 204

Like invisible sunglasses, the ozone layer filters out these dangerous rays. So when ozone is converted to oxygen gas, the UV rays are able to pass through to the earth (4). When UV rays damage the DNA in skin cells, it can lead to skin cancer. It is estimated that every [1%] drop in the atmospheric ozone concentration leads to a [6%] increase in skin cancers. (23)

Front 205

1. The world currently produces fewer than 200,000 tons of CFCs annually, down from ____ levels of _._ million tons. (23)

Back 205

The world currently produces fewer than 200,000 tons of CFCs annually, down from [1986] levels of [1.1] million tons. (23)

Front 206

1. Most of the CFCs manufactured since they were invented are still in use in air conditioners and aerosols and have not yet _______ the atmosphere. As these CFCs move slowly upward through the atmosphere, the problem can be expected to continue. Ozone depletion is _____ producing major ozone holes over the Antarctic. (23)

Back 206

Most of the CFCs manufactured since they were invented are still in use in air conditioners and aerosols and have not yet [REACHED] the atmosphere. As these CFCs move slowly upward through the atmosphere, the problem can be expected to continue. Ozone depletion is [STILL] producing major ozone holes over the Antarctic. (23)

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1. The worldwide reduction in CFC production is having a _____ impact. The period of maximum ozone depletion will peak in the next few years, and researchers’’ models predict that after that the situation should gradually improve and that the ozone layer will recover by the middle of the 21st century. Clearly, global environmental problems ___ be solved by concerted action. (23)

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The worldwide reduction in CFC production is having a [MAJOR] impact. The period of maximum ozone depletion will peak in the next few years, and researchers’’ models predict that after that the situation should gradually improve and that the ozone layer will recover by the middle of the 21st century. Clearly, global environmental problems [CAN] be solved by concerted action. (23)

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1. Key Learning Outcome 1.6 – Industrially produced CFCs catalytically _______ ozone in the upper atmosphere. (23)

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Key Learning Outcome 1.6 – Industrially produced CFCs catalytically [DESTROY] ozone in the upper atmosphere. (23)

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1. Scientists establish which general principles are true from among the many that might be by systematically testing ___________ proposals. If these proposals prove inconsistent with experimental observations, they are rejected as untrue. (24)

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Scientists establish which general principles are true from among the many that might be by systematically testing [ALTERNATIVE] proposals. If these proposals prove inconsistent with experimental observations, they are rejected as untrue. (24)

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1. After making careful observations concerning a particular area of science, scientists formulate an ___________ that might account for those observations. (24)

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After making careful observations concerning a particular area of science, scientists formulate an [EXPLANATION] that might account for those observations. (24)

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1. A hypothesis is a proposition that might be ____. (24)

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A hypothesis is a proposition that might be [TRUE]. (24)

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1. Those hypotheses that have not yet been _________ are retained, but they are always subject to future rejection if – in the light of new information – they are found to be _________. (24)

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Those hypotheses that have not yet been [DISPROVED] are retained, but they are always subject to future rejection if – in the light of new information – they are found to be [INCORRECT]. (24)

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1. We call the test of a hypothesis an __________. (24)

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We call the test of a hypothesis an [EXPERIMENT]. (24)

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1. A successful experiment is one in which one or more hypotheses are demonstrated to be ____________ with the results and are thus rejected. (24)

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A successful experiment is one in which one or more hypotheses are demonstrated to be [INCONSISTENT] with the results and are thus rejected. (24)

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1. Biology, like all science, is in a constant state of ______, with new ideas appearing and replacing old ones. (24)

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Biology, like all science, is in a constant state of [CHANGE], with new ideas appearing and replacing old ones. (24)

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1. Joseph Farman, who first reported the ozone hole, is a practicing scientist, and what he was doing in Antarctica was science. Science is a particular way of _____________ the world, of forming general rules about why things happen by observing particular situations. (24)

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Joseph Farman, who first reported the ozone hole, is a practicing scientist, and what he was doing in Antarctica was science. Science is a particular way of [INVESTIGATING] the world, of forming general rules about why things happen by observing particular situations. (24)

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1. A scientist like Farman is an observer, someone who looks at the world in order to __________ how it works. (24)

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A scientist like Farman is an observer, someone who looks at the world in order to [UNDERSTAND] how it works. (24)

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1. Scientific investigations can be said to have six stages as illustrated in figure 1.7: (1) _________ what is going on; (2) forming a set of __________; (3) making ___________; (4) _______ them and (5) carrying out controls, until one or more of the hypotheses have been __________; and (6) forming ___________ based on the remaining hypothesis. (24)

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Scientific investigations can be said to have six stages as illustrated in figure 1.7: (1) [OBSERVING] what is going on; (2) forming a set of [HYPOTHESES]; (3) making [PREDICTIONS]; (4) [TESTING] them and (5) carrying out controls, until one or more of the hypotheses have been [ELIMINATED]; and (6) forming [CONCLUSIONS] based on the remaining hypothesis. (24)

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1. (1) Observation. The key to any successful scientific investigation is careful observation. Farman and other scientists had studied the skies over the Antarctic for many years, noting a thousand details about temperature, light, and levels of chemicals. You can see an example in figure 1.8, where the purple colors represent the lowest levels of ozone that the scientists recorded. Had these scientists not kept careful records of what they ________, Farman might not have noticed that ozone levels were ________. (24)

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(1) Observation. The key to any successful scientific investigation is careful observation. Farman and other scientists had studied the skies over the Antarctic for many years, noting a thousand details about temperature, light, and levels of chemicals. You can see an example in figure 1.8, where the purple colors represent the lowest levels of ozone that the scientists recorded. Had these scientists not kept careful records of what they [OBSERVED], Farman might not have noticed that ozone levels were [DROPPING]. (24)

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1. (2) Hypothesis. When the unexpected drop in ozone was reported and questioned, environmental scientists made a guess to answer their questions – perhaps something was destroying the ozone; maybe the culprit was CFCs. Of course, this was not a guess in the true sense; scientists has some working knowledge of CFCs and what they might be doing in the upper atmosphere. We call such a guess a hypothesis. A hypothesis is a guess that might be ____. (25)

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(2) Hypothesis. When the unexpected drop in ozone was reported and questioned, environmental scientists made a guess to answer their questions – perhaps something was destroying the ozone; maybe the culprit was CFCs. Of course, this was not a guess in the true sense; scientists has some working knowledge of CFCs and what they might be doing in the upper atmosphere. We call such a guess a hypothesis. A hypothesis is a guess that might be [TRUE].(25)

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1. What the scientists guessed was that chlorine from CFCs was reacting chemically with ozone over the Antarctic, converting ozone (O3) into oxygen gas (O2) and in the process removing the ozone shield from our earth’s atmosphere. Often, scientists will form ___________ hypotheses if they have more than one guess about what they observe. In this case, there were several other hypotheses advanced to explain the ozone hole. One suggestion explained it as the result of convection: the ozone spun away from the polar regions much as water spins away from the center as a clothes washer moves through its spin cycle. Another hypothesis was that the ozone hole was a transient phenomenon, due perhaps to sunspots, and would soon disappear. (25)

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What the scientists guessed was that chlorine from CFCs was reacting chemically with ozone over the Antarctic, converting ozone (O3) into oxygen gas (O2) and in the process removing the ozone shield from our earth’s atmosphere. Often, scientists will form [ALTERNATIVE] hypotheses if they have more than one guess about what they observe. In this case, there were several other hypotheses advanced to explain the ozone hole. One suggestion explained it as the result of convection: the ozone spun away from the polar regions much as water spins away from the center as a clothes washer moves through its spin cycle. Another hypothesis was that the ozone hole was a transient phenomenon, due perhaps to sunspots, and would soon disappear. (25)

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1. (3) Predictions. If the CFC hypothesis is correct, then several consequences can reasonably be expected. We call these expected consequences predictions. A prediction is what you ______ to happen if a hypothesis is true. (25)

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(3) Predictions. If the CFC hypothesis is correct, then several consequences can reasonably be expected. We call these expected consequences predictions. A prediction is what you [EXPECT] to happen if a hypothesis is true. (25)

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1. The CFC hypothesis predicts that if CFCs are responsible for producing the ozone hole, then it should be possible to detect CFCs in the upper Antarctic atmosphere as well as the ________ released from CFCs that attach the ozone. (25)

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The CFC hypothesis predicts that if CFCs are responsible for producing the ozone hole, then it should be possible to detect CFCs in the upper Antarctic atmosphere as well as the [CHLORINE] released from CFCs that attach the ozone. (25)

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1. (4) Testing. Scientists set out to test the CFC hypothesis by attempting to ______ some of its predictions. As already mentioned, the test of a hypothesis is an experiment. To test the hypothesis, atmospheric samples were collected from the stratosphere over 6 miles up by a high-altitude balloon. Analysis of the samples revealed CFCs, as predicted. Were the CFCs interacting with the ozone? The samples contained free chlorine and fluorine, confirming the breakdown of CFC molecules. The results of the __________ thus support the hypothesis. (25)

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(4) Testing. Scientists set out to test the CFC hypothesis by attempting to [VERIFY] some of its predictions. As already mentioned, the test of a hypothesis is an experiment. To test the hypothesis, atmospheric samples were collected from the stratosphere over 6 miles up by a high-altitude balloon. Analysis of the samples revealed CFCs, as predicted. Were the CFCs interacting with the ozone? The samples contained free chlorine and fluorine, confirming the breakdown of CFC molecules. The results of the [EXPERIMENT] thus support the hypothesis. (25)

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1. (5) Controls. Events in the upper atmosphere can be influenced by many factors. We call each factor that might influence a process a variable. To evaluate alternative hypotheses about one variable, all the other variables must be kept constant so that we do not get misled or confused by these other influences. This is done by carrying out two experiments in parallel: In the first ____________ test, we alter one variable in a known way to test a particular hypothesis; in the second, called a _______ experiment, we do not alter that variable. In all other respects, the two experiments are the same. (25)

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(5) Controls. Events in the upper atmosphere can be influenced by many factors. We call each factor that might influence a process a variable. To evaluate alternative hypotheses about one variable, all the other variables must be kept constant so that we do not get misled or confused by these other influences. This is done by carrying out two experiments in parallel: In the first [EXPERIMENTAL] test, we alter one variable in a known way to test a particular hypothesis; in the second, called a [CONTROL] experiment, we do not alter that variable. In all other respects, the two experiments are the same. (25)

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1. To further test the CFC hypothesis, scientists carried out control experiments in which the key ________ was the amount of CFCs in the atmosphere. Working in laboratories, scientists reconstructed the atmospheric conditions, solar bombardment, and extreme temperatures found in the sky far above the Antarctic. If the ozone levels fell without addition of CFCs to the chamber, then CFCs could not be what was attacking the ozone. Carefully monitoring the chamber, however, scientists detected no drop in ozone levels in the _______ of CFCs. (25)

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To further test the CFC hypothesis, scientists carried out control experiments in which the key [VARIABLE] was the amount of CFCs in the atmosphere. Working in laboratories, scientists reconstructed the atmospheric conditions, solar bombardment, and extreme temperatures found in the sky far above the Antarctic. If the ozone levels fell without addition of CFCs to the chamber, then CFCs could not be what was attacking the ozone. Carefully monitoring the chamber, however, scientists detected no drop in ozone levels in the [ABSENCE] of CFCs. (25)

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1. (6) Conclusion. A hypothesis that has been tested and not ________ is tentatively accepted. The hypothesis that CFCs released into the atmosphere are destroying the earth’s protective ozone shield is now supported by a great deal of ____________ evidence and is widely accepted. While other factors have also been implicated in ozone depletion, destruction by CFCs is clearly the dominant phenomenon. (25)

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(6) Conclusion. A hypothesis that has been tested and not [REJECTED] is tentatively accepted. The hypothesis that CFCs released into the atmosphere are destroying the earth’s protective ozone shield is now supported by a great deal of [EXPERIMENTAL] evidence and is widely accepted. While other factors have also been implicated in ozone depletion, destruction by CFCs is clearly the dominant phenomenon. (25)

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1. A collection of related hypotheses that have been tested many times and not rejected is called a ______. A theory indicates a higher degree of certainty; however, in science, nothing is “certain.” The theory of the ozone shield – that ozone in the upper atmosphere shields the earth’s surface from harmful UV rays by absorbing them – is supported by a wealth of ___________ and experimentation and is widely accepted. The explanation for the destruction of this shield is still at the hypothesis stage. (25)

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A collection of related hypotheses that have been tested many times and not rejected is called a theory. A theory indicates a higher degree of certainty; however, in science, nothing is “certain.” The theory of the ozone shield – that ozone in the upper atmosphere shields the earth’s surface from harmful UV rays by absorbing them – is supported by a wealth of [OBSERVATION] and experimentation and is widely accepted. The explanation for the destruction of this shield is still at the hypothesis stage. (25)

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1. Key Learning Outcome 1.7 – Science progresses by systematically ___________ potential hypotheses that are not consistent with observation. (25)

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Key Learning Outcome 1.7 – Science progresses by systematically [ELIMINATING] potential hypotheses that are not consistent with observation. (25)

Front 230

1. A theory is a unifying ___________ for a broad range of observations. Theories are the solid ground of science, that of which we are the most certain. (26)

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A theory is a unifying [EXPLANATION] for a broad range of observations. Theories are the solid ground of science, that of which we are the most certain. (26)

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1. There is no absolute truth in science, however, only varying degrees of ___________. The possibility always remains that future evidence will cause a theory to be revised. (26)

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There is no absolute truth in science, however, only varying degrees of [UNCERTAINTY]. The possibility always remains that future evidence will cause a theory to be revised. (26)

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1. A scientist’s acceptance of a theory is always ___________. As information is shared throughout the scientific community, previous hypotheses and theories may be modified, and scientists may formulate new ideas. (26)

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A scientist’s acceptance of a theory is always [PROVISIONAL]. As information is shared throughout the scientific community, previous hypotheses and theories may be modified, and scientists may formulate new ideas. (26)

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1. Very active areas of science are often alive with ___________, as scientists grope with new and challenging ideas. This uncertainty is not a sign of poor science bur rather of the push and pull that is the heart of the scientific process. (26)

Back 233

Very active areas of science are often alive with [CONTROVERSY], as scientists grope with new and challenging ideas. This uncertainty is not a sign of poor science bur rather of the push and pull that is the heart of the scientific process. (26)

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1. The word theory is thus used very differently by scientists than by the general public. To a scientist, a theory represents that for which he or she is most _______; to the general public, the word theory implies a lack of knowledge or a guess. How often have you heard someone say, “It’s only a theory!”? (26)

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The word theory is thus used very differently by scientists than by the general public. To a scientist, a theory represents that for which he or she is most [CERTAIN]; to the general public, the word theory implies a lack of knowledge or a guess. How often have you heard someone say, “It’s only a theory!”? (26)

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1. It was once fashionable to claim that scientific progress is the result of applying a series of steps called the scientific method; that is, a series of logical “either/or” predictions tested by experiments to reject one alternative. This is ___ true. (26)

Back 235

It was once fashionable to claim that scientific progress is the result of applying a series of steps called the scientific method; that is, a series of logical “either/or” predictions tested by experiments to reject one alternative. This is [NOT] true. (26)

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1. A hypothesis that a successful scientist tests is not just any hypothesis. Rather, it is a “hunch” or ________ _____ in which the scientist integrates all that he or she knows. It is _______ and imagination that play a large role in scientific progress. (26)

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A hypothesis that a successful scientist tests is not just any hypothesis. Rather, it is a “hunch” or [EDUCATED GUESS] in which the scientist integrates all that he or she knows. It is [INSIGHT] and imagination that play a large role in scientific progress. (26)

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1. Scientific study is limited to organisms and _________ that we are able to observe and measure. Supernatural and _________ phenomena are beyond the realm of scientific analysis because they cannot be scientifically studied, analyzed, or explained. (26)

Back 237

Scientific study is limited to organisms and [PROCESSES] that we are able to observe and measure. Supernatural and [RELIGIOUS] phenomena are beyond the realm of scientific analysis because they cannot be scientifically studied, analyzed, or explained. (26)

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1. While scientific study has revolutionized our world, it cannot be relied upon to _____ all problems. Science identifies solutions to problems when solutions exist, but it cannot ______ solutions when they don’t. (26)

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While scientific study has revolutionized our world, it cannot be relied upon to [SOLVE] all problems. Science identifies solutions to problems when solutions exist, but it cannot [INVENT] solutions when they don’t. (26)

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1. Key Learning Outcome 1.8 – A scientist does not follow a fixed method to form hypotheses but relies also on ________ and _________. (26)

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Key Learning Outcome 1.8 – A scientist does not follow a fixed method to form hypotheses but relies also on [JUDGMENT] and [INTUITION]. (26)

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1. All organisms are composed of _____, life’s basic units. (28)

Back 240

All organisms are composed of [CELLS], life’s basic units. (28)

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1. Cells were discovered by Robert _____ in England in 1665, while he was using one of the first microscopes, one that magnified 30 times. Looking through a thin slice of cork, he observed many tiny chambers that reminded him of monks’ cells in a monastery. Not long after that, the Dutch scientist Anton van ___________ used microscopes capable of magnifying 300 times and discovered an amazing world of single-celled life in a drop of pond water like in figure 1.10. He called the bacterial and protist cells he say “wee animalcules.” In 1839, the German biologists Matthias _________ and Theodor _______, summarizing a large number of observations by themselves and others, concluded that all living organisms consist of cells. Their conclusion forms the basis of what has come to be known as the cell theory. Later, biologists added the idea that all cells come from other cells, the cell theory, one of the basic ideas in biology, is the foundation for understanding the reproduction and growth of all organisms. (28)

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Cells were discovered by Robert [HOOKE] in England in 1665, while he was using one of the first microscopes, one that magnified 30 times. Looking through a thin slice of cork, he observed many tiny chambers that reminded him of monks’ cells in a monastery. Not long after that, the Dutch scientist Anton van [LEEUWENHOEK] used microscopes capable of magnifying 300 times and discovered an amazing world of single-celled life in a drop of pond water like in figure 1.10. He called the bacterial and protist cells he say “wee animalcules.” In 1839, the German biologists Matthias [SCHLEIDEN] and Theodor [SCHWANN], summarizing a large number of observations by themselves and others, concluded that all living organisms consist of cells. Their conclusion forms the basis of what has come to be known as the cell theory. Later, biologists added the idea that all cells come from other cells, the cell theory, one of the basic ideas in biology, is the foundation for understanding the reproduction and growth of all organisms. (28)

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1. Even the simplest cell is incredibly complex, more intricate than a computer. The information that specifies what a cell is like – its detailed plan – is encoded in a long cable-like ________ called DNA (deoxyribonucleic acid). (28)

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Even the simplest cell is incredibly complex, more intricate than a computer. The information that specifies what a cell is like – its detailed plan – is encoded in a long cable-like [MOLECULE] called DNA (deoxyribonucleic acid). (28)

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1. Researchers James ______ and Francis _____ discovered in 1953 that each DNA molecule is formed from two long chains of building blocks, called nucleotides, wound around each other. You can see in figure 1.11 that the two chains face each other, like two lines of people holding hands. The chains contain information in the same way this sentence does – as a sequence of letters. There are four different nucleotides in DNA (symbolized as A, T, C, and G in the figure), and the sequence in which they occur encodes the information. Specific sequences of several hundred to many thousand nucleotides make up a gene, a discrete unit of hereditary information. A gene might encode a particular protein or a different kind of unique molecule called RNA, or a gene might act to regulate other genes. (28)

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Researchers James [WATSON] and Francis [CRICK] discovered in 1953 that each DNA molecule is formed from two long chains of building blocks, called nucleotides, wound around each other. You can see in figure 1.11 that the two chains face each other, like two lines of people holding hands. The chains contain information in the same way this sentence does – as a sequence of letters. There are four different nucleotides in DNA (symbolized as A, T, C, and G in the figure), and the sequence in which they occur encodes the information. Specific sequences of several hundred to many thousand nucleotides make up a gene, a discrete unit of hereditary information. A gene might encode a particular protein or a different kind of unique molecule called RNA, or a gene might act to regulate other genes. (28)

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1. All organisms on earth encode their genes in strands of DNA. This prevalence of DNA led to the development of the gene theory. Illustrated in figure 1.12, the gene theory states that the ________ and RNA molecules encoded by an organism’s genes determine what it will be like. (28)

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All organisms on earth encode their genes in strands of DNA. This prevalence of DNA led to the development of the gene theory. Illustrated in figure 1.12, the gene theory states that the [PROTEINS] and RNA molecules encoded by an organism’s genes determine what it will be like. (28)

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1. The entire set of DNA instructions that specifies a cell is called its genome. The sequence of the human genome, 3 _______ nucleotides long, was decoded in ____, a triumph of scientific investigation. (28)

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The entire set of DNA instructions that specifies a cell is called its genome. The sequence of the human genome, 3 [BILLION] nucleotides long, was decoded in [2001], a triumph of scientific investigation. (28)

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1. Figure 1.10 – Life in a drop of pond water – All _________ are composed of cells. Some organisms, including these protists, are single-celled, while others, such as plants, animals, and fungi, consist of many cells. (28)

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Figure 1.10 – Life in a drop of pond water – All [ORGANISMS] are composed of cells. Some organisms, including these protists, are single-celled, while others, such as plants, animals, and fungi, consist of many cells. (28)

Front 247

1. Figure 1.11 – Genes are made of DNA – Winding around each other like the rails of a spiral staircase, the two strands of a DNA molecule make a ______ _____. Because of its size and shape, the nucleotide represented by the letter A can only pair with the nucleotide represented by the letter T, and likewise G can only pair with C. (28)

Back 247

Figure 1.11 – Genes are made of DNA – Winding around each other like the rails of a spiral staircase, the two strands of a DNA molecule make a [DOUBLE HELIX]. Because of its size and shape, the nucleotide represented by the letter A can only pair with the nucleotide represented by the letter T, and likewise G can only pair with C. (28)

Front 248

1. Figure 1.12 – The gene theory – The gene theory states that what an organism is like is determined in large measure by its genes. Here you see how the many kinds of cells in the body of each of us are determined by which genes are used in making each particular kind of ____. (29)

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Figure 1.12 – The gene theory – The gene theory states that what an organism is like is determined in large measure by its genes. Here you see how the many kinds of cells in the body of each of us are determined by which genes are used in making each particular kind of [CELL]. (29)

Front 249

1. Figure 1.12 – The gene theory – (1) A human body contains over ___ different kinds of cells. (29)

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Figure 1.12 – The gene theory – (1) A human body contains over ___ different kinds of cells. (29)

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1. Figure 1.12 – The gene theory – (2) A human cell has 46 chromosomes, containing some 3 _______ nucleotides of DNA. (29)

Back 250

Figure 1.12 – The gene theory – (2) A human cell has 46 chromosomes, containing some 3 [BILLION] nucleotides of DNA. (29)

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1. Figure 1.12 – The gene theory – (3) A typical human chromosome can contain up to a ________ genes, arrayed along a linear piece of DNA. (29)

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Figure 1.12 – The gene theory – (3) A typical human chromosome can contain up to a [THOUSAND] genes, arrayed along a linear piece of DNA. (29)

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1. Figure 1.12 – The gene theory – (4) Each gene is composed of a sequence of several _______ to many _________ of DNA nucleotides and functions as a discrete unit of information. (29)

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Figure 1.12 – The gene theory – (4) Each gene is composed of a sequence of several [HUNDRED] to many [THOUSANDS] of DNA nucleotides and functions as a discrete unit of information. (29)

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1. Figure 1.12 – The gene theory – (5) All cells contain the same set of genes, but different kinds of cells use different genes. The production of specific proteins _____ for by these genes determines what the cell is like. (29)

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Figure 1.12 – The gene theory – (5) All cells contain the same set of genes, but different kinds of cells use different genes. The production of specific proteins [CODED] for by these genes determines what the cell is like. (29)

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1. The storage of __________ information in genes composed of DNA is common to all living things. (30)

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The storage of [HEREDITARY] information in genes composed of DNA is common to all living things. (30)

Front 255

1. The theory of heredity, first advanced by Gregor ______ in 1865, states that the genes of an organism are inherited as ________ units. A triumph of experimental science developed long before genes and DNA were understood. (30)

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The theory of heredity, first advanced by Gregor [MENDEL] in 1865, states that the genes of an organism are inherited as [DISCRETE] units. A triumph of experimental science developed long before genes and DNA were understood. (30)

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1. Soon after Mendel’s theory gave rise to the field of genetics, other biologists proposed what has come to be called the chromosomal theory of inheritance, which in its simplest form states that the _____ of Mendel’s theory are physically located on chromosomes and that it is because chromosomes are parceled out in a regular manner during ____________ that Mendel’s regular patterns of inheritance are seen. (30)

Back 256

Soon after Mendel’s theory gave rise to the field of genetics, other biologists proposed what has come to be called the chromosomal theory of inheritance, which in its simplest form states that the [GENES] of Mendel’s theory are physically located on chromosomes and that it is because chromosomes are parceled out in a regular manner during [REPRODUCTION] that Mendel’s regular patterns of inheritance are seen. (30)

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1. In modern terms, the two theories (theory of heredity and theory of inheritance) state that genes are a _________ of a cell’s chromosomes (like the 23 pairs of human chromosomes you see in figure 1.13) and that the regular ___________ of these chromosomes during sexual reproduction is responsible for the pattern of inheritance we call Mendelian segregation. (30)

Back 257

In modern terms, the two theories (theory of heredity and theory of inheritance) state that genes are a [COMPONENT] of a cell’s chromosomes (like the 23 pairs of human chromosomes you see in figure 1.13) and that the regular [DUPLICATION] of these chromosomes during sexual reproduction is responsible for the pattern of inheritance we call Mendelian segregation. (30)

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1. The unity of life’s mechanisms among many related life-forms contrasts with the incredible _________ of living things that have _______ to fill the varied environments of Earth. (30)

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The unity of life’s mechanisms among many related life-forms contrasts with the incredible [DIVERSITY] of living things that have [EVOLVED] to fill the varied environments of Earth. (30)

Front 259

1. Biologists sort organisms into kingdoms based on general _______________ in common. (30)

Back 259

Biologists sort organisms into kingdoms based on general [CHARACTERISTICS] in common. (30)

Front 260

1. In recent years, biologists have added a classification level above kingdoms, based on fundamental differences in ____ _________. (30)

Back 260

In recent years, biologists have added a classification level above kingdoms, based on fundamental differences in [CELL STRUCTURE. (30)

Front 261

1. The six kingdoms are each now assigned into one of three great group called domains: ________, _______, and _______ (figure 1.14). (30)

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The six kingdoms are each now assigned into one of three great group called domains: [BACTERIA], [ARCHAEA], and [EUKARYA] (figure 1.14). (30)

Front 262

1. The theory of evolution, advanced by Charles Darwin in 1859, attributes the diversity of the living world to _______ _________. (30)

Back 262

The theory of evolution, advanced by Charles Darwin in 1859, attributes the diversity of the living world to [NATURAL SELECTION]. (30)

Front 263

1. Those _________ best able to respond to the challenges of living will leave more offspring, he (Charles Darwin) argued (natural selection), and thus their traits become more ______ in the population. (30)

Back 263

Those [ORGANISMS] best able to respond to the challenges of living will leave more offspring, he (Charles Darwin) argued (natural selection), and thus their traits become more [COMMON] in the population. (30)

Front 264

1. It is because the world offers diverse opportunities that it contains so many different ____-_____. (30)

Back 264

It is because the world offers diverse opportunities that it contains so many different [LIFE-FORMS]. (30)

Front 265

1. Today scientists can decipher the thousands of genes (the _______) of an organism. (30)

Back 265

Today scientists can decipher the thousands of genes (the [GENOMES]) of an organism. (30)

Front 266

1. One of the great triumphs of science in the century and a half since Darwin is the detailed understanding of how Darwin’s theory of evolution is related to the ____ ______ – of how changes in life’s diversity can result from changes in __________ genes (figure 1.15). (30)

Back 266

One of the great triumphs of science in the century and a half since Darwin is the detailed understanding of how Darwin’s theory of evolution is related to the [GENE THEORY] – of how changes in life’s diversity can result from changes in [INDIVIDUAL] genes (figure 1.15). (30)

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1. Key Learning Outcome 1.9 – The theories uniting biology state that cellular organisms store __________ information in DNA. (30)

Back 267

Key Learning Outcome 1.9 – The theories uniting biology state that cellular organisms store [HEREDITARY] information in DNA. (30)

Front 268

1. Sometimes DNA ___________ occur, which when preserved result in evolutionary change. Today’s biological _________ is the product of a long evolutionary journey. (30)

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Sometimes DNA [ALTERATIONS] occur, which when preserved result in evolutionary change. Today’s biological [DIVERSITY] is the product of a long evolutionary journey. (30)

Front 269

1. Figure 1.13 – Human Chromosomes – The chromosomal theory of ___________ states that genes are located on chromosomes. This human karyotype (an ordering of chromosomes) shows banding patterns on chromosomes that represent clusters of _____. (30)

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Figure 1.13 – Human Chromosomes – The chromosomal theory of [INHERITANCE] states that genes are located on chromosomes. This human karyotype (an ordering of chromosomes) shows banding patterns on chromosomes that represent clusters of [GENES]. (30)

Front 270

1. Figure 1.14 – The three domains of life – Biologists categorize all ______ things into three overarching groups called domains: Bacteria, Archaea, and _______. Domain Bacteria contains the kingdom Bacteria, and domain Archaea contains the kingdom Archaea. (30)

Back 270

Figure 1.14 – The three domains of life – Biologists categorize all [LIVING] things into three overarching groups called domains: Bacteria, Archaea, and [EUKARYA]. Domain Bacteria contains the kingdom Bacteria, and domain Archaea contains the kingdom Archaea. (30)

Front 271

1. Domain Eukarya is composed of four more kingdoms: ________, _______, _____, and ________. (30)

Back 271

Domain Eukarya is composed of four more kingdoms: [PROTISTA], [PLANTAE], [FUNGI], and [ANIMALIA]. (30)

Front 272

1. Figure 1.15 – The theory of evolution – Darwin’s theory of evolution proposes that many forms of a ____ may exist among members of a __________ and that those members with a form better suited to their particular habitat will tend to reproduce more successfully, and so their ______ become more common in the population, a process Darwin dubbed “natural selection.” Here you see how this process is thought to have worked on two pivotal genes that helped generate the _________ of finches on the Galapagos Islands, visited by Darwin in 1831 on his round-the-world voyage on HMS Beagle.

Back 272

Figure 1.15 – The theory of evolution – Darwin’s theory of evolution proposes that many forms of a [GENE] may exist among members of a [POPULATION] and that those members with a form better suited to their particular habitat will tend to reproduce more successfully, and so their [TRAITS] become more common in the population, a process Darwin dubbed “natural selection.” Here you see how this process is thought to have worked on two pivotal genes that helped generate the [DIVERSITY] of finches on the Galapagos Islands, visited by Darwin in 1831 on his round-the-world voyage on HMS Beagle.

Front 273

1.1.1 Biology is the study of life. All living organisms share common _______________, but they are also diverse and are categorized into six groups called ________. (33)

Back 273

Biology is the study of life. All living organisms share common [CHARACTERISTICS], but they are also diverse and are categorized into six groups called [KINGDOMS]. (33)

Front 274

1.2.1 All living organisms share five basic properties: ________ ____________, metabolism, ___________, growth and reproduction, and ________. (33)

Back 274

1.2.1 All living organisms share five basic properties: [CELLULAR ORGANIZATION], metabolism, [HOMEOSTASIS], growth and reproduction, and [HEREDITY]. (33)

Front 275

Cellular ____________ indicates that all living organisms are composed of cells. (33)

Back 275

Cellular [ORGANIZATION] indicates that all living organisms are composed of cells. (33)

Front 276

Metabolism means that all living organisms, like the kingfisher shown here from figure 1.3, use ______. (33)

Back 276

Metabolism means that all living organisms, like the kingfisher shown here from figure 1.3, use [ENERGY]. (33)

Front 277

Homeostasis is the process whereby all living organisms maintain stable ________ conditions. (33)

Back 277

Homeostasis is the process whereby all living organisms maintain stable [INTERNAL] conditions. (33)

Front 278

The properties of ______ ___ ____________ indicate that all living organisms grow in size and reproduce. (33)

Back 278

The properties of [GROWTH AND REPRODUCTION] indicate that all living organisms grow in size and reproduce. (33)

Front 279

The property of heredity describes how all living organisms possess _______ information in DNA that determines how each organism looks and functions, and this information is passed on to future ___________. (33)

Back 279

The property of heredity describes how all living organisms possess [GENETIC] information in DNA that determines how each organism looks and functions, and this information is passed on to future [GENERATIONS]. (33)

Front 280

1.3.1 Living organisms exhibit increasing levels of complexity within their cells (________ _____), within their bodies (__________ _____), and within ecosystems (____________ _____). (33)

Back 280

Living organisms exhibit increasing levels of complexity within their cells ([CELLULAR LEVEL]), within their bodies ([ORGANISMAL LEVEL]), and within ecosystems ([POPULATIONAL LEVEL]). (33)

Front 281

1.3.2 Novel properties that appear in each level of the hierarchy of life are called ________ __________. (33)

Back 281

Novel properties that appear in each level of the hierarchy of life are called [EMERGENT PROPERTIES]. (33)

Front 282

1.4.1 Five themes emerge from the study of biology: _________, ___ ____ __ ______, ___________, _________ __________ ________, and ___________. These themes are used to examine the similarities and differences among organisms. (33)

Back 282

Five themes emerge from the study of biology: [EVOLUTION], [THE FLOW OF ENERGY], [COOPERATION], [STRUCTURE DETERMINES FUNCTION], and [HOMEOSTASIS]. These themes are used to examine the similarities and differences among organisms. (33)

Front 283

1.5.1 Mathematics uses general __________ to explain specific situations. (33)

Back 283

Mathematics uses general [PRINCIPLES] to explain specific situations. (33)

Front 284

1.5.2 _________ reasoning is the process of using general principles to explain individual observations. _________ reasoning is the process of using specific observations to formulate general principles. (33)

Back 284

[DEDUCTIVE] reasoning is the process of using general principles to explain individual observations. [INDUCTIVE] reasoning is the process of using specific observations to formulate general principles. (33)

Front 285

1.6.1 Scientists observed a ________ of the ozone layer over Antarctica. Their scientific investigation of the “ozone hole” revealed that industrially produced ____ were responsible for the thinning of the ozone layer in the earth’s atmosphere (figure 1.6). (33)

Back 285

Scientists observed a [THINNING] of the ozone layer over Antarctica. Their scientific investigation of the “ozone hole” revealed that industrially produced [CFCs] were responsible for the thinning of the ozone layer in the earth’s atmosphere (figure 1.6). (33)

Front 286

1.7.1 Scientists use ____________ to formulate hypotheses. (33)

Back 286

1.7.1 Scientists use [OBSERVATIONS] to formulate hypotheses. (33)

Front 287

Hypotheses are possible ____________ that are used to form predictions. These predictions are tested ______________. (33)

Back 287

Hypotheses are possible [EXPLANATIONS] that are used to form predictions. These predictions are tested [EXPERIMENTALLY]. (33)

Front 288

Some hypotheses are ________ based on experimental results, while others are tentatively accepted. (33)

Back 288

Some hypotheses are [REJECTED] based on experimental results, while others are tentatively accepted. (33)

Front 289

1.7.2 Scientific investigations often use a series of ______, called the scientific process, to _____ a scientific question.

Back 289

1.7.2 Scientific investigations often use a series of [STAGES], called the scientific process, to [STUDY] a scientific question.

Front 290

The stages (in the scientific process) are ____________, forming __________, making ___________, _______, establishing ________, and drawing ___________. (33)

Back 290

The stages (in the scientific process) are [OBSERVATIONS], forming [HYPOTHESES], making [PREDICTIONS], [TESTING], establishing [CONTROLS], and drawing [CONCLUSIONS]. (33)

Front 291

The discovery of the hole in the ozone required careful ____________ of data collected from the atmosphere. Scientists proposed a __________ to explain what caused a decrease in the levels of ozone over the Antarctic. They then formed ___________ and tested the hypothesis against controls. (33)

Back 291

The discovery of the hole in the ozone required careful [OBSERVATIONS] of data collected from the atmosphere. Scientists proposed a [HYPOTHESIS] to explain what caused a decrease in the levels of ozone over the Antarctic. They then formed [PREDICTIONS] and tested the hypothesis against controls. (33)

Front 292

1.8.1 __________ that hold up to testing over time are combined into statements called theories. Theories carry a higher degree of certainty, although no theory in science is ________. (33)

Back 292

[HYPOTHESES] that hold up to testing over time are combined into statements called theories. Theories carry a higher degree of certainty, although no theory in science is [ABSOLUTE]. (33)

Front 293

1.8.2 Science can only _____ what can be tested experimentally, a hypothesis can only be established through science if it can be tested and potentially _________. (33)

Back 293

Science can only [STUDY] what can be tested experimentally, a hypothesis can only be established through science if it can be tested and potentially [DISPROVEN]. (33)

Front 294

1.9.1 There are four unifying theories in biology: ____ theory, ____ theory, the theory of ________, and the theory of _________. (33)

Back 294

1.9.1 There are four unifying theories in biology: [CELL] theory, [GENE] theory, the theory of [HEREDITY], and the theory of [EVOLUTION]. (33)

Front 295

The cell theory states that all living organisms are composed of cells, which grow and _________ to form other cells. (33)

Back 295

The cell theory states that all living organisms are composed of cells, which grow and [REPRODUCE] to form other cells. (33)

Front 296

1.9.2 The gene theory states that long _________ of DNA carry instructions for producing cellular components. These instructions are encoded in the __________ sequences in the strands of DNA, like this section of DNA from figure 1.11. (33)

Back 296

1.9.2 The gene theory states that long [MOLECULES] of DNA carry instructions for producing cellular components. These instructions are encoded in the [NUCLEOTIDE] sequences in the strands of DNA, like this section of DNA from figure 1.11. (33)

Front 297

The nucleotides are organized into discrete _____ called genes, and the genes determine how an organism looks and _________. (33)

Back 297

The nucleotides are organized into discrete [UNITS] called genes, and the genes determine how an organism looks and [FUNCTIONS]. (33)

Front 298

1.9.3 The theory of ________ states that the genes of an organism are passed as discrete _____ from parent to offspring. (33)

Back 298

1.9.3 The theory of heredity states that the genes of an organism are passed as discrete [UNITS] from parent to offspring. (33)

Front 299

1.9.4 Organisms are organized into kingdoms based on similar _______________. (33)

Back 299

1.9.4 Organisms are organized into kingdoms based on similar [CHARACTERISTICS]. (33)

Front 300

The kingdoms are further organized into three major groups called _______ based on their ________ characteristics. (33)

Back 300

The kingdoms are further organized into three major groups called [DOMAINS] based on their [CELLULAR] characteristics. (33)

Front 301

The three domains are ________, _______, and _______. (33)

Back 301

The three domains are [BACTERIA], [ARCHAEA], and [EUKARYA]. (33)

Front 302

The theory of evolution states that _____________ in genes that are passed from parent to offspring result in changes in future generations. These changes lead to greater _________ among organisms over time. (33)

Back 302

The theory of evolution states that [MODIFICATIONS] in genes that are passed from parent to offspring result in changes in future generations. These changes lead to greater [DIVERSITY] among organisms over time. (33)

Front 303

1.1.1 Biologists categorize all living things based on related characteristics into large groups called: (34)

a. Kingdoms.
b. Species.
c. Populations.
d. Ecosystems.

Back 303

1.1.1 Biologists categorize all living things based on related characteristics into large groups called: (34)

a. Kingdoms.

Front 304

1.2.1a Living things can be distinguished from nonliving things because they have: (34)

a. Complexity.
b. Movement.
c. Cellular organization.
d. Response to a stimulus.

Back 304

1.2.1a Living things can be distinguished from nonliving things because they have: (34)

c. Cellular organization.

Front 305

1.2.1b – In Fred Hoyle’s science fiction novel The Black Cloud, the earth is approached by a large interstellar cloud of gas. As the cloud orients around the sun, scientists discover that the cloud is feeding, absorbing the sun’s energy through the excitation of electrons in the outer energy levels of cloud molecules, a process similar to the photosynthesis that occurs on earth. Different portions of the cloud are isolated from each other by associations of ions created by this excitation. Electron currents pass between these sectors, much as they do on the surface of the human brain, and endow the cloud with self-awareness, memory and the ability to reason. Using electricity produced by static discharges, the cloud is able to communicate with human beings and to describe its history. The cloud tells our scientists that it once was smaller but has grown by absorbing molecules and energy from stars like our sun, on which it has been grazing. Eventually the cloud moves off in search of other stars. Is the cloud alive? Explain. (34)

Back 305

The cloud appears to be alive because it possesses several fundamental properties of life, including internal organization, energy transfer, growth, and possibly homeostasis. However, a key property of life that the cloud does not seem to possess is that of heredity. Although the cloud grows, it does not seem capable of reproducing offspring that carry characteristics passed on from the parent. Without this key characteristic, the cloud would not be considered alive.

Front 306

1.3.1 Living things are organized. Choose the answer that illustrates this organization and that is arranged from smallest to largest: (34)

a. Cell, atom, molecule, tissue, organelle, organ, organ system, organism, population, species, community, ecosystem.
b. Atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, species, community, ecosystem.
c. Atom molecule, organelle, cell, tissue, organ, organ system, organism, community, population, species, ecosystem.
d. Atom, molecule, cell wall, cell, organ, organelle, organism, species, population, community, ecosystem.

Back 306

1.3.1 Living things are organized. Choose the answer that illustrates this organization and that is arranged from smallest to largest: (34)

b. Atom, molecule, organelle, cell, tissue, organ, organ system, organism, population, species, community, ecosystem.

Front 307

1.3.2 At each level in the hierarchy of living things, properties occur that were not present at the simpler levels. These properties are referred to as: (34)

a. Novelistic properties.
b. Complex properties.
c. Incremental properties.
d. Emergent properties.

Back 307

1.3.2 At each level in the hierarchy of living things, properties occur that were not present at the simpler levels. These properties are referred to as: (34)

d. Emergent properties.

Front 308

1.3.2b Which of the following is not an emergent property: (34)

a. Metabolism
b. Movement
c. Cellular organization
d. Consciousness

Back 308

1.3.2b Which of the following is not an emergent property: (34)

c. Cellular organization

Front 309

1.4.1 The five general biological themes include: (34)

a. Evolution, energy flow, competition, structure determines function, and homeostasis.
b. Evolution, energy flow, cooperation, structure determines function, and homeostasis.
c. Evolution, growth, competition, structure determines function, and homeostasis.
d. Evolution, growth, cooperation, structure determines function, and homeostasis.

Back 309

1.4.1 The five general biological themes include: (34)

b. Evolution, energy flow, cooperation, structure determines function, and homeostasis.

Front 310

1.5.1 You notice that on cloudy days people often carry umbrellas, folded or in a case. You also not that when umbrellas are open, there are many car accidents. You conclude that open umbrellas cause car accidents. Explain the type of reasoning used to reach this conclusion and why it can sometimes be a problem. (34)

Back 310

You notice that on cloudy days people often carry umbrellas, folded or in a case. You also not that when umbrellas are open, there are many car accidents. You conclude that open umbrellas cause car accidents. Explain the type of reasoning used to reach this conclusion and why it can sometimes be a problem. (34)

This is an example of inductive reasoning. The problem is that people sometimes assume that because two items both occur at the same time, one of the events causes the other. In this case both events are caused by a third event that was not mentioned – the fact that it is raining. There is nothing wrong with the process of inductive reasoning, but do no assume that correlation (occurring together) implies causation.

Front 311

1.5.2 When you are trying to understand something new, you begin by observation and then put the observations together in a logical fashion to form a general principle. This method is called: (34)

a. Inductive reasoning.
b. Rule enhancement.
c. Theory production.
d. Deductive reasoning.

Back 311

1.5.2 When you are trying to understand something new, you begin by observation and then put the observations together in a logical fashion to form a general principle. This method is called: (34)

a. Inductive reasoning.

Front 312

1.6.1 CFCs: (34)

a. Produce chlorine gas.
b. Cause global warming.
c. Are carcinogens.
d. Bind to chromosomes.

Back 312

1.6.1 CFCs: (34)

a. Produce chlorine gas.

Front 313

1.7.1 When trying to figure out explanations for observations, scientists construct a series of possible hypotheses. Then they make predictions and: (34)

a. Test each hypothesis, using appropriate controls, to determine which hypothesis is true.
b. Test each hypothesis, using appropriate controls, to rule out as many hypotheses as possible.
c. Use logic to determine which hypothesis is true.
d. Reject those that seem unlikely.

Back 313

1.7.1 When trying to figure out explanations for observations, scientists construct a series of possible hypotheses. Then they make predictions and: (34)

b. Test each hypothesis, using appropriate controls, to rule out as many hypotheses as possible.

Front 314

1.7.2 Which of the following statements is correct regarding a hypothesis? (34)

a. After sufficient testing, you can conclude that it is true.
b. If it explains the observations, it doesn’t need to be tested.
c. After sufficient testing, you can accept it as probable, being aware that it may be revised or rejected in the future.
d. You never have any degree of certainty that it is true; there are too many variables.

Back 314

1.7.2 Which of the following statements is correct regarding a hypothesis? (34)

c. After sufficient testing, you can accept it as probable, being aware that it may be revised or rejected in the future.

Front 315

1.8.1 St. John’s wort is an herb that has been used for hundreds of years as a remedy for mile depression. How might a modern-day scientist research its effectiveness? (34)

Back 315

St. John’s wort is an herb that has been used for hundreds of years as a remedy for mile depression. How might a modern-day scientist research its effectiveness? (34)

Use the scientific process to set up a series of experiments using people who are not depressed and people who are mildly depressed, and give them fixed amounts of a placebo (a substance used as a control that doesn’t have any drug effects – in experiments involving a pill, a placebo is often a sugar pill), or St. John’s wort, over some period of time. Test them for mild depression before and after the experiment, and do not tell them who is receiving the drug and who is receiving the placebo. You may have to vary the amount of the herb used, and perhaps the amount of time needed to establish consistent levels of the herb in the body.

Front 316

1.8.2 The scientific method is: (34)

a. Rationalizing a large body of observations.
b. Resting predictions repeatedly.
c. Followed in the same manner in all investigations.
d. Testing a series of “either/or” predictions.

Back 316

1.8.2 The scientific method is: (34)

d. Testing a series of “either/or” predictions.

Front 317

1.9.1 Cell theory states that: (34)

a. All organisms have cell walls.
b. All cellular organisms undergo sexual reproduction.
c. All living organisms use cells for energy, either their own or they ingest cels of other organisms.
d. All living organisms consist of cells that come from other cells.

Back 317

1.9.1 Cell theory states that: (34)

d. All living organisms consist of cells that come from other cells.

Front 318

1.9.2 The gene theory states that all the information that specifies what a cell is and what it does: (34)

a. Is different for each cell type in the organism.
b. Is passed down, unchanged, from parents to offspring.
c. Is contained in a long molecule called DNA.
d. All of the above.

Back 318

1.9.2 The gene theory states that all the information that specifies what a cell is and what it does: (34)

c. Is contained in a long molecule called DNA.

Front 319

1.9.3 The chromosomal theory of inheritance states that: (34)

a. Chromosomes contain DNA.
b. Humans have 23 pairs of chromosomes.
c. All cells have genes.
d. Genes are on chromosomes.

Back 319

1.9.3 The chromosomal theory of inheritance states that: (34)

d. Genes are on chromosomes.

Front 320

1.9.4 The theory of evolution by natural selection was advanced in 1859 by: (34)

a. Gregor Mendel.
b. Charles Darwin.
c. James Watson and Francis Crick.
d. Robert Hooke.

Back 320

1.9.4 The theory of evolution by natural selection was advanced in 1859 by: (34)

b. Charles Darwin.

Front 321

The study of the properties of the substances that all things living and nonliving are created from. The branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.

Back 321

1. Chemistry (36)

Front 322

Any substance in the universe that has mass and occupies space.

Back 322

1. Matter (36)

Front 323

A core (nucleus) of protons and neutrons surrounded by an orbiting cloud of electrons. The chemical behavior of an ____ is largely determined by the distribution of its electrons, particularly the number of electrons in its outermost level.

Back 323

1. Atoms (36)

Front 324

A subatomic particle in the nucleus of an atom that carries a positive charge. The number of _______ determines the chemical character of the atom because it dictates the number of electrons orbiting the nucleus and available for chemical activity.

Back 324

1. Protons (36)

Front 325

A subatomic particle located within the nucleus of an atom. Similar to a proton in mass, but as its name implies, a _______ is neutral and possesses no charge.

Back 325

1. Neutrons (36)

Front 326

A subatomic particle with a negative electrical charge. The negative charge of one ________exactly balances the positive charge of one proton. _________ orbit the atom’s positively charged nucleus and determine its chemical properties.

Back 326

1. Electron (36)

Front 327

The number of protons in the nucleus of an atom. In an atom that does not bear an electric charge (that is, one that is not an ion), the ______ ______ is also equal to the number of electrons.

Back 327

1. Atomic Number (36)

Front 328

A substance that cannot be separated into different substances by ordinary chemical methods.

Back 328

1. Element (36)

Front 329

The ____ ______ of an atom consists of the combined mass of all of its protons and neutrons.

Back 329

1. Mass Number (36)

Front 330

The capacity to bring about change, to do work.

Back 330

1. Energy (37)

Front 331

The volume of space around a nucleus where an electron is most likely to be found.

Back 331

1. Orbital (37)

Front 332

An atom in which the number of electrons does not equal the number of protons. An ___ carries an electrical charge.

Back 332

1. Ions (38)

Front 333

An atom that has the same number of protons but different numbers of neutrons.

Back 333

1. Isotopes (38)

Front 334

The process by which a nucleus of an unstable atom loses energy by emitting ionizing radiation.

Back 334

1. Radioactive Decay (aka Nuclear Decay or Radioactivity) (38)

Front 335

A radioactive substance that is taken up and used by the body.

Back 335

1. Tracer (38)

Front 336

Any record of prehistoric life – generally taken to mean older than 10,000 years.

Back 336

1. Fossil (39)

Front 337

A widely employed method of dating fossils less than 50,000 years old is the carbon-14 (14C) _____________ ______. Any method of determining the age of earth materials or objects of organic origin based on measurement of either short-lived radioactive elements or the amount of a long-lived radioactive element plus its decay product.

Back 337

1. Radioisotopic Dating (39)

Front 338

The length of time it takes for half of a radioactive substance to decay.

Back 338

1. Half-Life (39)

Front 339

The smallest unit of a compound that displays the properties of that compound.

Back 339

1. Molecule (40)

Front 340

The force holding two atoms together. The force can result from the attraction of opposite charges (ionic bond) or from the sharing of one or more pairs of electrons (a covalent bond).

Back 340

1. Chemical Bond (40)

Front 341

A chemical bond formed between ions as a result of the attraction of opposite electrical charges.

Back 341

1. Ionic Bonds (40)

Front 342

A chemical bond formed by the sharing of one or more pairs of electrons.

Back 342

1. Covalent Bonds (41)

Front 343

A molecule with positively and negatively charged ends. One portion of a _____ ________ attracts electrons more strongly than another portion, with the result that the molecule has electron-rich (-) and electron-poor (+) regions, giving it magnet-like positive and negative poles. Water is one of the most _____ _________ known.

Back 343

1. Polar Molecules (41)

Front 344

Molecules that don’t exhibit a large difference in electronegativities of its atoms, like the carbon-hydrogen bonds of methane, are called ________ _________ and contain ________ covalent bonds.

Back 344

1. Nonpolar Molecules (41)

Front 345

A molecular force formed by the attraction of the partial positive charge of one hydrogen atom of a water molecule with the partial negative charge of the oxygen atom of another.

Back 345

1. Hydrogen Bond (42)

Front 346

The molecular attraction between the surfaces of like bodies in contact, such as that between water molecules and other water molecules.

Back 346

1. Cohesion (44)

Front 347

The molecular attraction exerted between the surfaces of unlike bodies in contact, as water molecules to the walls of the narrow tubes that occur in plants.

Back 347

1. Adhesion (44)

Front 348

Describes polar molecules, which form hydrogen bonds with water and therefore are soluble in water.

Back 348

1. Hydrophilic (44)

Front 349

Refers to polar molecules that dissolve in water and are surrounded by a hydration shell.

Back 349

1. Soluble (44)

Front 350

Describes nonpolar molecules, which do not form hydrogen bonds with water and therefore are not soluble in water.

Back 350

1. Hydrophobic (44)

Front 351

The positively charged ___ of ________, H+; formed by removal of the electron from atomic ________ and found in the form of hydronium ___ in all aqueous solutions of acids.

Back 351

1. Hydrogen Ion (45)

Front 352

A negatively charged particle of _________ (OH-) of any base in a water solution.

Back 352

1. Hydroxide Ion (45)

Front 353

The process of spontaneous ion formation. One of the principal ways that radiation, such as charged particles and X rays, transfers its energy to matter. In chemistry, __________ often occurs in a liquid solution.

Back 353

1. Ionization (45)

Front 354

Any substance that dissociates to form H+ ions when dissolved in water. Having a pH value less than 7.

Back 354

1. Acid (45)

Front 355

Any substance that combines with H+ ions thereby reducing the H+ ion concentration of a solution. Having a pH value above 7.

Back 355

1. Base (45)

Front 356

Rainfall made sufficiently acidic by atmospheric pollution that it causes environmental harm, typically to forests and lakes. The main cause is the industrial burning of coal and other fossil fuels, the waste gases from which contain sulfur and nitrogen oxides, which combine with atmospheric water to form acids.

Back 356

1. Acid Rain (46)

Front 357

A substance that takes up or releases hydrogen ions (H+) to maintain the pH within a certain range.

Back 357

1. Buffer (47)

Front 358

1. Atoms: Chemistry – study of the properties of __________.

Back 358

Atoms: Chemistry – study of the properties of [SUBSTANCES].

Front 359

1. Atoms: Matter – any substance that has ____ and occupies _____.

Back 359

Atoms: Matter – any substance that has [MASS] and occupies [SPACE].

Front 360

1. Atoms: Atoms – smallest particle into which a substance can be divided and still retain its ________ properties.

Back 360

Atoms: Atoms – smallest particle into which a substance can be divided and still retain its [CHEMICAL] properties.

Front 361

Atoms: Protons – Subatomic particle with a ________ charge and are part of a very dense _______ of an atom.

Back 361

Atoms: Protons – Subatomic particle with a [POSITIVE] charge and are part of a very dense [NUCLEUS] of an atom.

Front 362

Atoms: Neutron – Subatomic particle without a charge (_______) and are part of a very dense nucleus of an ____.

Back 362

Atoms: Neutron – Subatomic particle without a charge ([NEUTRAL]) and are part of a very dense nucleus of an [ATOM].

Front 363

Atoms: Electron – Subatomic particle with a ________ charge that ______ the core nucleus.

Back 363

Atoms: Electron – Subatomic particle with a [NEGATIVE] charge that [ORBITS] the core nucleus.

Front 364

1. Atoms: Atoms – What does an atom really look like?

Back 364

Atoms: Atoms – What does an atom really look like?

Front 365

Atoms: Atomic Number – number of _______ in the nucleus.

Back 365

Atoms: Atomic Number – number of [PROTONS] in the nucleus.

Front 366

Atoms: Element – atoms with the same ______ number that have the same chemical properties.

Back 366

Atoms: Element – atoms with the same [ATOMIC] number that have the same chemical properties.

Front 367

1. Atoms: Mass Number – number of _______ and ________.

Back 367

Atoms: Mass Number – number of [PROTONS] and [NEUTRONS].

Front 368

1. Atoms: Energy – ability to ____.

Back 368

Atoms: Energy – ability to [WORK].

Front 369

1. Atoms: Potential Energy – energy of position (drive ________ _________).

Back 369

Atoms: Potential Energy – energy of position (drive [CHEMICAL REACTIONS]).

Front 370

1. Atoms: Energy levels are called ________ ______.

Back 370

Atoms: Energy levels are called [ELECTRON SHELLS].

Front 371

1. Atoms: Orbital – volume of space around the nucleus where an ________ is most likely to be found.

Back 371

Atoms: Orbital – volume of space around the nucleus where an [ELECTRON] is most likely to be found.

Front 372

Electron Shells: Each electron shell has a specific number of ________.

Back 372

Electron Shells: Each electron shell has a specific number of [ORBITALS].

Front 373

1. Ions and Isotopes: Ion – atoms in which the number of electrons does not equal the number of _______ (gain or loss of electron).

Back 373

Ions and Isotopes: Ion – atoms in which the number of electrons does not equal the number of [PROTONS] (gain or loss of electron).

Front 374

Ions and Isotopes: Isotopes – same number of protons, but different numbers of ________.

Back 374

Ions and Isotopes: Isotopes – same number of protons, but different numbers of [NEUTRONS].

Front 375

Ions and Isotopes: Radioactive Decay – _______ tends to break up into particles with lower atomic number.

Back 375

Ions and Isotopes: Radioactive Decay – [NUCLEUS] tends to break up into particles with lower atomic number.

Front 376

1. Ions and Isotopes: Tracer – radioactive substance that is taken up and used by the ____.

Back 376

Ions and Isotopes: Tracer – radioactive substance that is taken up and used by the [BODY].

Front 377

Ions and Isotopes: Tracers are helpful in identifying _________ tumors.

Back 377

Ions and Isotopes: Tracers are helpful in identifying [CANCEROUS] tumors.

Front 378

Ions and Isotopes: Fossils – created by the remains, footprints, or other traces of _________ that become buried in sand or sediment.

Back 378

Ions and Isotopes: Fossils – created by the remains, footprints, or other traces of [ORGANISMS] that become buried in sand or sediment.

Front 379

Ions and Isotopes: Radioisotopic dating – method of dating fossils less than 50,000 years old using ______-__.

Back 379

Ions and Isotopes: Radioisotopic dating – method of dating fossils less than 50,000 years old using [CARBON-14].

Front 380

Ions and Isotopes: After an organism dies carbon-14 decays, but no additional carbon-12 is taken into the ____.

Back 380

Ions and Isotopes: After an organism dies carbon-14 decays, but no additional carbon-12 is taken into the [BODY].

Front 381

Ions and Isotopes: The ratio of carbon-14 to carbon-12 decreases by ½ every _,___ years (half-life).

Back 381

Ions and Isotopes: The ratio of carbon-14 to carbon-12 decreases by ½ every [5,730] years (half-life).

Front 382

1. Molecules: Molecule – a group of _____ held together by energy.

Back 382

Molecules: Molecule – a group of [ATOMS] held together by energy.

Front 383

1. Molecules: Chemical Bond – energy or force holding two atoms together (_____ bonds,________ bonds, ________ bonds, ___ ___ _____ ______).

Back 383

Molecules: Chemical Bond – energy or force holding two atoms together ([IONIC] bonds, [COVALENT] bonds, [HYDROGEN] bonds, [VAN DER WAALS FORCES]).

Front 384

Molecules: Ionic bonds – atoms are attracted to each other by ________ electrical charges.

Back 384

Molecules: Ionic bonds – atoms are attracted to each other by [OPPOSITE] electrical charges.

Front 385

Molecules: Covalent bonds – between two atoms when they _____ electrons.

Back 385

Molecules: Covalent bonds – between two atoms when they [SHARE] electrons.

Front 386

1. Molecules: Covalent bonds – between two _____ when they share electrons.

Back 386

Molecules: Covalent bonds – between two [ATOMS] when they share electrons.

Front 387

1. Molecules: Polar molecules – have ________ and ________ ends “poles.”

Back 387

Molecules: Polar molecules – have [POSITIVE] and [NEGATIVE] ends “poles.”

Front 388

Molecules: Nonpolar molecules – don’t exhibit a large difference in _________________ of its atoms.

Back 388

Molecules: Nonpolar molecules – don’t exhibit a large difference in [ELECTRONEGATIVITIES] of its atoms.

Front 389

Molecules: Hydrogen bond – positive end of one polar molecule is _________ to the negative end of another.

Back 389

Molecules: Hydrogen bond – positive end of one polar molecule is [ATTRACTED] to the negative end of another.

Front 390

1. Molecules: Van der Waals Forces – ___-___________ attractive force that occurs when two atoms are very close to one another.

Back 390

Molecules: Van der Waals Forces – [NON-DIRECTIONAL] attractive force that occurs when two atoms are very close to one another.

Front 391

1. _____: 2H2 + O2 → 2H2O

Back 391

[WATER]: 2H2 + O2 → 2H2O

Front 392

1. Water: ________ bonds give water unique properties.

Back 392

Water: [HYDROGEN] bonds give water unique properties.

Front 393

1. Water: Heat Storage – Many hydrogen bonds that water molecules form with one another need a large input of thermal ______ to disrupt the organization of liquid water and raise its ___________.

Back 393

Water: Heat Storage – Many hydrogen bonds that water molecules form with one another need a large input of thermal [ENERGY] to disrupt the organization of liquid water and raise its [TEMPERATURE].

Front 394

Water: ________ ____ – the energy needed to raise the temperature of 1g of a substance 1˚C.

Back 394

Water: [SPECIFIC HEAT] – the energy needed to raise the temperature of 1g of a substance 1˚C.

Front 395

Water: Ice Formation – A lattice of hydrogen bonds assume a _______-____ structure, forming a solid.

Back 395

Water: Ice Formation – A lattice of hydrogen bonds assume a [CRYSTAL-LIKE] structure, forming a solid.

Front 396

1. Water: High heat of vaporization – High ____________ causes many hydrogen bonds to break in water with the result that the liquid is changed into vapor.

Back 396

Water: High heat of vaporization – High [TEMPERATURES] causes many hydrogen bonds to break in water with the result that the liquid is changed into vapor.

Front 397

Water: Cohesion – the attraction of between a _____ molecule to another _____ molecule.

Back 397

Water: Cohesion – the attraction of between a [POLAR] molecule to another [POLAR] molecule.

Front 398

Water: Adhesion – A polar molecule is attracted to the polar molecule of another _________.

Back 398

Water: Adhesion – A polar molecule is attracted to the polar molecule of another [SUBSTANCE].

Front 399

1. Water: High Polarity – Water molecules in solution always tend to form the maximum number of hydrogen _____ possible.

Back 399

Water: High Polarity – Water molecules in solution always tend to form the maximum number of hydrogen [BONDS] possible.

Front 400

1. Water: Hydrophilic – “_____ ______.”

Back 400

Water: Hydrophilic – “[WATER LOVING].”

Front 401

Water: Soluble – ______ of water form around all polar molecules and the polar molecules ________ in water.

Back 401

Water: Soluble – [SHELLS] of water form around all polar molecules and the polar molecules [DISSOLVE] in water.

Front 402

1. Water: High Polarity – Water molecules in solution always tend to form the _______ number of hydrogen bonds possible.

Back 402

Water: High Polarity – Water molecules in solution always tend to form the [MAXIMUM] number of hydrogen bonds possible.

Front 403

1. Water: ___________ – “water fearing.”

Back 403

Water: [HYDROPHOBIC] – “water fearing.”

Front 404

1. Water: ________ molecules are forced into association with one another, crowded together to minimize their disruption of the ________ bonding of water.

Back 404

Water: [NONPOLAR] molecules are forced into association with one another, crowded together to minimize their disruption of the [HYDROGEN] bonding of water.

Front 405

Water Ionizes: Hydrogen Ion (H+) – positively charged hydrogen ion due to the loss of a(n) ________.

Back 405

Water Ionizes: Hydrogen Ion (H+) – positively charged hydrogen ion due to the loss of a(n) [ELECTRON].

Front 406

Water Ionizes: Hydroxide Ion (OH-) – __________ charged ion due to the gain of an electron.

Back 406

Water Ionizes: Hydroxide Ion (OH-) – [NEGATIVELY] charged ion due to the gain of an electron.

Front 407

1. Water Ionizes: Ionization – spontaneous ion _________.

Back 407

Water Ionizes: Ionization – spontaneous ion [FORMATION].

Front 408

1. Water Ionizes: pH – expression of the _____________ of H+ in solution.

Back 408

Water Ionizes: pH – expression of the [CONCENTRATION] of H+ in solution.

Front 409

Water Ionizes: Acids – substance that ___________ in water to increase the concentration of H+ in water.

Back 409

Water Ionizes: Acids – substance that [DISSOCIATED] in water to increase the concentration of H+ in water.

Front 410

1. Water Ionizes: Bases – substance that ________ with H+ in water.

Back 410

Water Ionizes: Bases – substance that [COMBINES] with H+ in water.

Front 411

1. Water Ionizes: Buffers – substance that takes up or releases hydrogen ions into solution as the hydrogen ion concentration of the solution _______. Resist change in pH.

Back 411

Water Ionizes: Buffers – substance that takes up or releases hydrogen ions into solution as the hydrogen ion concentration of the solution [CHANGES]. Resist change in pH.

Front 412

1. Biology is the science of life, and all life, in fact even all _______, is made of __________. (36)

Back 412

Biology is the science of life, and all life, in fact even all [NONLIFE], is made of [SUBSTANCES]. (36)

Front 413

1. Chemistry is the study of the __________ of these substances. So, while it may seem tedious or unrelated to examine chemistry in a biology text, it is essential. (36)

Back 413

Chemistry is the study of the [PROPERTIES] of these substances. So, while it may seem tedious or unrelated to examine chemistry in a biology text, it is essential. (36)

Front 414

1. Organisms are ________ machines (figure 2.1), and to understand them we must learn a little chemistry. (36)

Back 414

Organisms are [CHEMICAL] machines (figure 2.1), and to understand them we must learn a little chemistry. (36)

Front 415

1. Any substance in the universe that has ____ and occupies _____ is defined as matter. (36)

Back 415

Any substance in the universe that has [MASS] and occupies [SPACE] is defined as matter. (36)

Front 416

1. All matter is composed of extremely small particles called _____. (36)

Back 416

All matter is composed of extremely small particles called [ATOMS]. (36)

Front 417

1. An atom is the smallest particle into which a substance can be _______ and still retain its chemical properties. (36)

Back 417

An atom is the smallest particle into which a substance can be [DIVIDED] and still retain its chemical properties. (36)

Front 418

1. Every atom has the same basic _________ you see in figure 2.2. (36)

Back 418

Every atom has the same basic [STRUCTURE] you see in figure 2.2. (36)

Front 419

1. At the center of every ____ is a small, very dense nucleus formed of two types of _________ particles, protons (illustrated by purple balls) and neutrons (the pink balls). Whizzing around the core is an orbiting cloud of a third kind of subatomic particle, the electron (depicted by yellow balls on concentric rings). (36)

Back 419

At the center of every [ATOM] is a small, very dense nucleus formed of two types of [SUBATOMIC] particles, protons (illustrated by purple balls) and neutrons (the pink balls). Whizzing around the core is an orbiting cloud of a third kind of subatomic particle, the electron (depicted by yellow balls on concentric rings). (36)

Front 420

1. ________ have no electrical charge, whereas _______ have a positive charge and _________ have a negative one. (36)

Back 420

[NEUTRONS] have no electrical charge, whereas [PROTONS] have a positive charge and [ELECTRONS] have a negative one. (36)

Front 421

1. In a typical ____, there is an orbiting electron for every proton in the nucleus. The electron’s negative charge balances the proton’s positive charge, so the atom is electrically _______. (36)

Back 421

In a typical [ATOM], there is an orbiting electron for every proton in the nucleus. The electron’s negative charge balances the proton’s positive charge, so the atom is electrically [NEUTRAL]. (36)

Front 422

1. An atom is typically described by the number of _______ in its nucleus or by the overall ____ of the atom. The terms mass and weight are often used interchangeably, but they have slightly different meaning. (36)

Back 422

An atom is typically described by the number of [PROTONS] in its nucleus or by the overall [MASS] of the atom. The terms mass and weight are often used interchangeably, but they have slightly different meaning. (36)

Front 423

1. Mass refers to the ______ of a substance, whereas weight refers to the force _______ exerts on a substance. Hence, an object has the same mass whether it is on the earth or the moon, but its weight will be greater on the earth, because the earth’s gravitational force is greater than the moon’s. For example, an astronaut weighting 180 pounds on Earth will weigh about 30 pounds on the moon. He didn’t lose any significant mass during his flight to the moon; there is just less gravitational pull on his mass. (36)

Back 423

Mass refers to the [AMOUNT] of a substance, whereas weight refers to the force [GRAVITY] exerts on a substance. Hence, an object has the same mass whether it is on the earth or the moon, but its weight will be greater on the earth, because the earth’s gravitational force is greater than the moon’s. For example, an astronaut weighting 180 pounds on Earth will weigh about 30 pounds on the moon. He didn’t lose any significant mass during his flight to the moon; there is just less gravitational pull on his mass. (36)

Front 424

1. The number of protons in the _______ of an atom is called the atomic number. For example, the atomic number of carbon is 6 because it has six protons. (36)

Back 424

The number of protons in the [NUCLEUS] of an atom is called the atomic number. For example, the atomic number of carbon is 6 because it has six protons. (36)

Front 425

1. Atoms with the same atomic number (that is, the same number of protons) have the same ________ __________ and are said to belong to the same element. (36)

Back 425

Atoms with the same atomic number (that is, the same number of protons) have the same [CHEMICAL PROPERTIES] and are said to belong to the same element. (36)

Front 426

1. An element is any substance that cannot be ______ ____ into any other substance by ordinary chemical means. (36)

Back 426

An element is any substance that cannot be [BROKEN DOWN] into any other substance by ordinary chemical means. (36)

Front 427

1. Neutrons are similar to protons in ____, and the number of protons and neutrons in the nucleus of an atom is called the ____ ______. (36)

Back 427

Neutrons are similar to protons in [MASS], and the number of protons and neutrons in the nucleus of an atom is called the [MASS NUMBER]. (36)

Front 428

1. A carbon atom that has six _______ and six ________ has a mass number of 12. (36)

Back 428

A carbon atom that has six [PROTONS] and six [NEUTRONS] has a mass number of 12. (36)

Front 429

1. An electron’s contribution to the overall ____ of an atom is negligible. (36)

Back 429

An electron’s contribution to the overall [MASS] of an atom is negligible. (36)

Front 430

1. The atomic numbers and mass numbers of some of the most ______ elements on Earth are shown in table 2.1. (36)

Back 430

The atomic numbers and mass numbers of some of the most [COMMON] elements on Earth are shown in table 2.1. (36)

Front 431

1. Figure 2.1 – Replacing electrolytes. During extreme exercise, athlete will often consume drinks that contain “electrolytes,” chemical such as calcium, potassium, and sodium that play an important role in muscle contraction. Electrolytes can also be depleted in other types of ___________. (36)

Back 431

Figure 2.1 – Replacing electrolytes. During extreme exercise, athlete will often consume drinks that contain “electrolytes,” chemical such as calcium, potassium, and sodium that play an important role in muscle contraction. Electrolytes can also be depleted in other types of [DEHYDRATION]. (36)

Front 432

1. Figure 2.2 – Basic structure of atoms. All atoms have a nucleus consisting of protons and neutrons, except ________, the smallest atom, which has only one proton and no neutrons in its nucleus. Carbon, for example, has six protons and six neutrons in its nucleus. (36)

Back 432

Figure 2.2 – Basic structure of atoms. All atoms have a nucleus consisting of protons and neutrons, except [HYDROGEN], the smallest atom, which has only one proton and no neutrons in its nucleus. Carbon, for example, has six protons and six neutrons in its nucleus. (36)

Front 433

1. Electrons spin around the nucleus in ________ a far distance away from the nucleus. The electrons determine how atoms _____ with each other. (36)

Back 433

Electrons spin around the nucleus in [ORBITALS] a far distance away from the nucleus. The electrons determine how atoms [REACT] with each other. (36)

Front 434

1. Table 2.1 – Elements Common in Living Organisms (36)

Back 434

1. Table 2.1 – Elements Common in Living Organisms (36)

Front 435

1. _________ have very little mass (only about 1/1,840 the mass of a proton). (37)

Back 435

[ELECTRONS] have very little mass (only about 1/1,840 the mass of a proton). (37)

Front 436

1. Of all the mass contributing to your weight, the portion that is contributed by electrons is less than the mass of your eyelashes. And yet electrons determine the ________ ________ of atoms because they are the parts of atoms that come close enough to each other in nature to interact. (37)

Back 436

Of all the mass contributing to your weight, the portion that is contributed by electrons is less than the mass of your eyelashes. And yet electrons determine the [CHEMICAL BEHAVIOR] of atoms because they are the parts of atoms that come close enough to each other in nature to interact. (37)

Front 437

1. Almost all the volume of an atom is _____ _____. Protons and neutrons lie at the core of this space, whereas orbiting electrons are very far from the nucleus. (37)

Back 437

Almost all the volume of an atom is [EMPTY SPACE]. Protons and neutrons lie at the core of this space, whereas orbiting electrons are very far from the nucleus. (37)

Front 438

1. If the nucleus of an atom were the size of an apple, the orbit of the nearest ________ would be more than a mile out! (37)

Back 438

If the nucleus of an atom were the size of an apple, the orbit of the nearest [ELECTRON] would be more than a mile out! (37)

Front 439

1. Because electrons are negatively charged, they are attracted to the positively charged nucleus, but they also _____ the negative charges of each other. (37)

Back 439

Because electrons are negatively charged, they are attracted to the positively charged nucleus, but they also [REPEL] the negative charges of each other. (37)

Front 440

1. It takes work to keep electrons in orbit, just as it takes work to hold an apple in your hand when gravity is pulling the apple down toward the ground. The apple in your hand is said to possess ______, the ability to do work, because of its position – if you were to release it, the apple would fall. (37)

Back 440

It takes work to keep electrons in orbit, just as it takes work to hold an apple in your hand when gravity is pulling the apple down toward the ground. The apple in your hand is said to possess [ENERGY], the ability to do work, because of its position – if you were to release it, the apple would fall. (37)

Front 441

1. Electrons have energy to position, called _________ energy. (37)

Back 441

Electrons have energy to position, called [POTENTIAL] energy. (37)

Front 442

1. It takes work to oppose the attraction of the nucleus, so moving the electron farther out from the nucleus, as shown by the set of arrows on the right side of figure 2.3, requires an input of energy and results in an electron with greater potential energy. Moving an electron in toward the nucleus has the opposite effect (the set of arrows on the left side); energy is ________, and the electron has less potential energy. (37)

Back 442

It takes work to oppose the attraction of the nucleus, so moving the electron farther out from the nucleus, as shown by the set of arrows on the right side of figure 2.3, requires an input of energy and results in an electron with greater potential energy. Moving an electron in toward the nucleus has the opposite effect (the set of arrows on the left side); energy is [RELEASED], and the electron has less potential energy. (37)

Front 443

1. Cells use the potential energy of atoms to drive ________ reactions. (37)

Back 443

Cells use the potential energy of atoms to drive [CHEMICAL] reactions. (37)

Front 444

1. While the energy levels of an atom are often visualized as well-defined circular orbits around a central nucleus as was shown in figure 2.2, such a simple picture is not accurate. These energy levels, called ________ ______, often consist of complex three-dimensional shapes, and the exact location of an individual electron at any given time is impossible to specify. However, some locations are more probable than others, and it is often possible to say where an electron is most likely to be _______. (37)

Back 444

While the energy levels of an atom are often visualized as well-defined circular orbits around a central nucleus as was shown in figure 2.2, such a simple picture is not accurate. These energy levels, called [ELECTRON SHELLS], often consist of complex three-dimensional shapes, and the exact location of an individual electron at any given time is impossible to specify. However, some locations are more probable than others, and it is often possible to say where an electron is most likely to be [LOCATED]. (37)

Front 445

1. The volume of space around a nucleus where an electron is most likely to be found is called the _______ of that electron. (37)

Back 445

The volume of space around a nucleus where an electron is most likely to be found is called the [ORBITAL] of that electron. (37)

Front 446

1. Each electron shell has a specific ______ of orbitals, and each orbital can hold up to ___ electrons. (37)

Back 446

Each electron shell has a specific [NUMBER] of orbitals, and each orbital can hold up to [TWO] electrons. (37)

Front 447

1. The first shell in any atom contains one s (_________) orbital. (37)

Back 447

The first shell in any atom contains one s ([SPHERICAL]) orbital. (37)

Front 448

1. Helium, shown in figure 2.4a, has one electron shell with one s orbital that corresponds to the ______ energy level. The orbital contains two electrons, shown above and below the nucleus. (37)

Back 448

Helium, shown in figure 2.4a, has one electron shell with one s orbital that corresponds to the [LOWEST] energy level. The orbital contains two electrons, shown above and below the nucleus. (37)

Front 449

1. In atoms with more than one electron shell, the second shell contains ____ p orbitals (each of them dumbbell-shaped rather than spherical) and holds up to _____ electrons. (37)

Back 449

In atoms with more than one electron shell, the second shell contains [FOUR] p orbitals (each of them dumbbell-shaped rather than spherical) and holds up to [EIGHT] electrons. (37)

Front 450

1. Nitrogen, shown in figure 2.4b, has two electron shells; the first one is completely filled with two electrons, but three of the four _ ________ in the second electron shell are not filled because nitrogen’s second shell contains only five electrons (openings in orbitals are indicated with dotted circles). (37)

Back 450

Nitrogen, shown in figure 2.4b, has two electron shells; the first one is completely filled with two electrons, but three of the four [P ORBITALS] in the second electron shell are not filled because nitrogen’s second shell contains only five electrons (openings in orbitals are indicated with dotted circles). (37)

Front 451

1. In atoms with more than two electron shells, subsequent shells also contain up to ____ orbitals and a maximum of _____ electrons. (37)

Back 451

In atoms with more than two electron shells, subsequent shells also contain up to [FOUR] orbitals and a maximum of [EIGHT] electrons. (37)

Front 452

1. Atoms with ________ electron orbitals tend to be more reactive because they lose, gain, or share electrons in order to fill their outermost electron shell. (37)

Back 452

Atoms with [UNFILLED] electron orbitals tend to be more reactive because they lose, gain, or share electrons in order to fill their outermost electron shell. (37)

Front 453

1. Losing, gaining, or sharing electrons is the basis for chemical reactions in which ________ _____ form between atoms. (37)

Back 453

Losing, gaining, or sharing electrons is the basis for chemical reactions in which [CHEMICAL BONDS] form between atoms. (37)

Front 454

1. Key Learning Outcome 2.1 – Atoms, the smallest particles into which a substance can be _______, are composed of electrons orbiting a _______ that contains protons and neutrons. (37)

Back 454

Key Learning Outcome 2.1 – Atoms, the smallest particles into which a substance can be [DIVIDED], are composed of electrons orbiting a [NUCLEUS] that contains protons and neutrons. (37)

Front 455

1. Electrons determine the chemical ________ of atoms. (37)

Back 455

Electrons determine the chemical [BEHAVIOR] of atoms. (37)

Front 456

1. Figure 2.3 – The electrons of atoms possess _________ energy. (37)

Back 456

Figure 2.3 – The electrons of atoms possess [POTENTIAL] energy. (37)

Front 457

1. Electrons that circulate rapidly around the nucleus contain energy, and depending on their ________ from the nucleus, they may contain more or less energy. (37)

Back 457

Electrons that circulate rapidly around the nucleus contain energy, and depending on their [DISTANCE] from the nucleus, they may contain more or less energy. (37)

Front 458

1. Energy level 1 is the ______ potential energy level because it is closest to the nucleus. (37)

Back 458

Energy level 1 is the [LOWEST] potential energy level because it is closest to the nucleus. (37)

Front 459

1. When an electron _______ energy, it moves from level 1 to the next higher energy level (level 2). When an electron _____ energy, it falls to a lower energy level closer to the nucleus. (37)

Back 459

When an electron [ABSORBS] energy, it moves from level 1 to the next higher energy level (level 2). When an electron [LOSES] energy, it falls to a lower energy level closer to the nucleus. (37)

Front 460

1. Figure 2.4 – Electrons in electron shells. (a) An atom of helium has two protons, two neutrons, and two electrons. The electrons fill the one orbital in its one ________ _____, the lowest energy level. (37)

Back 460

Figure 2.4 – Electrons in electron shells. (a) An atom of helium has two protons, two neutrons, and two electrons. The electrons fill the one orbital in its one [ELECTRON SHELL], the lowest energy level. (37)

Front 461

1. Sometimes an atom may ____ or ____ an electron from its outer shell. (38)

Back 461

Sometimes an atom may [GAIN] or [LOSE] an electron from its outer shell. (38)

Front 462

1. Atoms in which the number of electrons does not equal the number of protons because they have gained or lost one or more electrons are called ____. (38)

Back 462

Atoms in which the number of electrons does not equal the number of protons because they have gained or lost one or more electrons are called [IONS]. (38)

Front 463

1. All ions are electrically charged. For example, an atom of sodium (on the left in figure 2.5) becomes a positively charged ion, called a ______ (on the right), when it loses an electron, such that one proton in the nucleus is left with an unbalanced charge (11 positively charged protons and only 10 negatively charged electrons). (38)

Back 463

All ions are electrically charged. For example, an atom of sodium (on the left in figure 2.5) becomes a positively charged ion, called a [CATION] (on the right), when it loses an electron, such that one proton in the nucleus is left with an unbalanced charge (11 positively charged protons and only 10 negatively charged electrons). (38)

Front 464

1. Negatively charged ions, called ______, also form when an atom gains an electron from another atom. (38)

Back 464

Negatively charged ions, called [ANIONS], also form when an atom gains an electron from another atom. (38)

Front 465

1. The number of ________ in an atom of a particular element can vary without changing the chemical properties of the element. (38)

Back 465

The number of [NEUTRONS] in an atom of a particular element can vary without changing the chemical properties of the element. (38)

Front 466

1. Atoms that have the same number of protons but different number of neutrons are called ________. (38)

Back 466

Atoms that have the same number of protons but different number of neutrons are called [ISOTOPES]. (38)

Front 467

1. Isotopes of an atom have the same ______ number but differ in their ____ number. (38)

Back 467

Isotopes of an atom have the same [ATOMIC] number but differ in their [MASS] number. (38)

Front 468

1. ___________ isotopes are used in medicine and in dating fossils. (38)

Back 468

[RADIOACTIVE] isotopes are used in medicine and in dating fossils. (38)

Front 469

1. Isotopes can be used in many medical procedures. Short-lived isotopes, those that decay fairly rapidly and produce harmless products, are commonly used as _______ in the body. (38)

Back 469

Isotopes can be used in many medical procedures. Short-lived isotopes, those that decay fairly rapidly and produce harmless products, are commonly used as [TRACERS] in the body. (38)

Front 470

1. A ______ is a radioactive substance that is taken up and used by the body. (38)

Back 470

A [TRACER] is a radioactive substance that is taken up and used by the body. (38)

Front 471

1. Emissions from the radioactive _______ tracer are detected using special laboratory equipment and can reveal key diagnostic information about the functioning of the body. (38)

Back 471

Emissions from the radioactive [ISOTOPE] tracer are detected using special laboratory equipment and can reveal key diagnostic information about the functioning of the body. (38)

Front 472

1. PET and PET/CT (positron emission tomography/computerized tomography) imaging procedures can be used to identify a cancerous area in the body. First, a radioactive tracer is injected into the body. This tracer is taken up by all cells, but it is taken up in larger amounts in cells with higher metabolic activities, such as cancer cells. Images are then taken of the body, and areas emitting greater amounts of the tracer can be seen. For example, in the images in figure 2.7, the radioactive-emitting cancer site appears as a black area on the left and a yellow glowing area on the right. There are many other uses of radioactive isotopes in ________. (38)

Back 472

PET and PET/CT (positron emission tomography/computerized tomography) imaging procedures can be used to identify a cancerous area in the body. First, a radioactive tracer is injected into the body. This tracer is taken up by all cells, but it is taken up in larger amounts in cells with higher metabolic activities, such as cancer cells. Images are then taken of the body, and areas emitting greater amounts of the tracer can be seen. For example, in the images in figure 2.7, the radioactive-emitting cancer site appears as a black area on the left and a yellow glowing area on the right. There are many other uses of radioactive isotopes in [MEDICINE]. (38)

Front 473

1. Figure 2.6 – Isotopes of the element carbon. The three most ________ isotopes of carbon are carbon-12, carbon-13, and carbon-14. The yellow “clouds” in the diagrams represent the orbiting electrons, whose numbers are the same for all three isotopes. Protons are shown in purple, and neutrons are shown in pink. (38)

Back 473

Figure 2.6 – Isotopes of the element carbon. The three most [ABUNDANT] isotopes of carbon are carbon-12, carbon-13, and carbon-14. The yellow “clouds” in the diagrams represent the orbiting electrons, whose numbers are the same for all three isotopes. Protons are shown in purple, and neutrons are shown in pink. (38)

Front 474

1. Figure 2.7 – Using a radioactive tracer to identify cancer. In certain medical imaging procedures, the patient ingests or is injected intravenously with a radioactive tracer that is absorbed in greater amounts by cancer cells. The tracer emits radioactivity that is detected using ___ and ___/__ equipment. A cancerous area in the neck is seen in these two images, as a dark black area on the left and a bright yellow glowing area on the right. (39)

Back 474

Figure 2.7 – Using a radioactive tracer to identify cancer. In certain medical imaging procedures, the patient ingests or is injected intravenously with a radioactive tracer that is absorbed in greater amounts by cancer cells. The tracer emits radioactivity that is detected using [PET] and [PET/CT] equipment. A cancerous area in the neck is seen in these two images, as a dark black area on the left and a bright yellow glowing area on the right. (39)

Front 475

1. A ______ is any record of prehistoric life – generally taken to mean older than 10,000 years. (39)

Back 475

A [FOSSIL] is any record of prehistoric life – generally taken to mean older than 10,000 years. (39)

Front 476

1. By dating the _____ in which fossils occur, biologists can get a very good idea of how old the fossils are. (39)

Back 476

By dating the [ROCKS] in which fossils occur, biologists can get a very good idea of how old the fossils are. (39)

Front 477

1. Rocks are usually dated by measuring the degree of radioactive decay of certain radioactive ________ among rock-forming minerals. (39)

Back 477

Rocks are usually dated by measuring the degree of radioactive decay of certain radioactive [ISOTOPES] among rock-forming minerals. (39)

Front 478

1. A radioactive isotope is one whose nucleus is ________ and eventually flies apart, creating more stable atoms of another element. (39)

Back 478

A radioactive isotope is one whose nucleus is [UNSTABLE] and eventually flies apart, creating more stable atoms of another element. (39)

Front 479

1. Because the rate of decay of a radioactive element (the percent of isotopes that undergo decay in a minute) is ________, scientists can use the amount of radioactive decay to date fossils. The older the fossil, the greater the fraction of decayed radioactive isotopes. (39)

Back 479

Because the rate of decay of a radioactive element (the percent of isotopes that undergo decay in a minute) is [CONSTANT], scientists can use the amount of radioactive decay to date fossils. The older the fossil, the greater the fraction of decayed radioactive isotopes. (39)

Front 480

1. A widely employed method of dating fossils less than 50,000 years old is the carbon-14 (14C) radioisotopic dating method illustrated in figure 2.8. Most carbon atoms have a mass number of 12 (12C). However, a tiny but fixed proportion of the carbon atoms in the atmosphere consists of carbon atoms with a mass number of 14 (14C). This isotope of carbon is created by the bombardment of nitrogen-14 atoms with cosmic rays. This proportion of 14C (designated A in the figure) is captured by plants in photosynthesis and is the proportion present in the carbon molecules of the animal’s body that eats the plants, in this case a rabbit. After the plant or animal dies, it no longer accumulates carbon, and the 14C present at the time of death gradually decays over time back to nitrogen-14 (14N). The amount of 14C (A) decreases while the amount of 12C stays the same. Scientists can determine how long ago an organism died by measuring the ration of 14C to 12C in its remains or in the fossilized rock. Over time, the ratio of 14C to 12C decreases. It takes 5,730 years for half of the 14C (1/2A or A/2) present in the sample to be converted to 14N by this process. This length of time is called the half-life of the isotope. Because the half-life of an isotope is a constant that never changes, the extent of radioactive decay allows you to date a sample. Thus, a sample that had a quarter of its original proportion of 14C remaining (1/4A or A/4) would be approximately 11,460 years old (two half-lives – 5,730 years for half of the 14C to decay to a level of A/2 and another 5,730 years for the remaining 14C to decay to a level of A/4). (39)

Back 480

A widely employed method of dating fossils less than 50,000 years old is the carbon-14 (14C) radioisotopic dating method illustrated in figure 2.8. Most carbon atoms have a mass number of 12 (12C). However, a tiny but fixed proportion of the carbon atoms in the atmosphere consists of carbon atoms with a mass number of 14 (14C). This isotope of carbon is created by the bombardment of nitrogen-14 atoms with cosmic rays. This proportion of 14C (designated A in the figure) is captured by plants in photosynthesis and is the proportion present in the carbon molecules of the animal’s body that eats the plants, in this case a rabbit. After the plant or animal dies, it no longer accumulates carbon, and the 14C present at the time of death gradually decays over time back to nitrogen-14 (14N). The amount of 14C (A) decreases while the amount of 12C stays the same. Scientists can determine how long ago an organism died by measuring the ration of 14C to 12C in its remains or in the fossilized rock. Over time, the ratio of 14C to 12C decreases. It takes 5,730 years for half of the 14C (1/2A or A/2) present in the sample to be converted to 14N by this process. This length of time is called the half-life of the isotope. Because the half-life of an isotope is a constant that never changes, the extent of radioactive decay allows you to date a sample. Thus, a sample that had a quarter of its original proportion of 14C remaining (1/4A or A/4) would be approximately 11,460 years old (two half-lives – 5,730 years for half of the 14C to decay to a level of A/2 and another 5,730 years for the remaining 14C to decay to a level of A/4). (39)

Front 481

1. For fossils older than 50,000 years, there is too little 14C remaining to measure precisely, and scientists instead examine the decay of potassium-40 (40K) into argon-40 (40Ar), which has a ____-____ of 1.3 billion years. (39)

Back 481

For fossils older than 50,000 years, there is too little 14C remaining to measure precisely, and scientists instead examine the decay of potassium-40 (40K) into argon-40 (40Ar), which has a [HALF-LIFE] of 1.3 billion years. (39)

Front 482

1. Key Learning Outcome 2.2 – When an atom gains or loses one or more electrons, it is called a(n) ___. Isotopes of an element differ in the number of ________ they contain, but all have the same chemical properties. (39)

Back 482

Key Learning Outcome 2.2 – When an atom gains or loses one or more electrons, it is called a(n) [ION]. Isotopes of an element differ in the number of [NEUTRONS] they contain, but all have the same chemical properties. (39)

Front 483

1. Figure 2.8 – Radioactive isotope dating. This diagram illustrates radioactive dating using ______-__, a short-lived isotope. (39)

Back 483

Figure 2.8 – Radioactive isotope dating. This diagram illustrates radioactive dating using [CARBON-14], a short-lived isotope. (39)

Front 484

1. A ________ is a group of atoms held together by energy. The energy acts as “glue,” ensuring that the various atoms stick to one another.(40)

Back 484

A [MOLECULE] is a group of atoms held together by energy. The energy acts as “glue,” ensuring that the various atoms stick to one another.(40)

Front 485

1. The energy or force holding two atoms together is called a ________ ____. (40)

Back 485

The energy or force holding two atoms together is called a [CHEMICAL BOND]. (40)

Front 486

1. Chemical bonds determine the ______ of the large biological molecules. (40)

Back 486

Chemical bonds determine the [SHAPES] of the large biological molecules. (40)

Front 487

1. There are three principal kinds of chemical bonds: _____ bonds, where the force is generated by the attraction of oppositely charge ions; ________ bonds, where the force results from the sharing of electrons; and ________ bonds, where the force is generated by the attraction of opposite partial electrical charges. (40)

Back 487

There are three principal kinds of chemical bonds: [IONIC] bonds, where the force is generated by the attraction of oppositely charge ions; [COVALENT] bonds, where the force results from the sharing of electrons; and [HYDROGEN] bonds, where the force is generated by the attraction of opposite partial electrical charges. (40)

Front 488

1. Another type of chemical attraction called ___ ___ _____ forces will be discussed later, but keep in mind that this type of interaction is not considered a chemical bond. (40)

Back 488

Another type of chemical attraction called [VAN DER WAALS] forces will be discussed later, but keep in mind that this type of interaction is not considered a chemical bond. (40)

Front 489

1. Chemical bonds called ionic bonds form when atoms are attracted to each other by opposite __________ charges. (40)

Back 489

Chemical bonds called ionic bonds form when atoms are attracted to each other by opposite [ELECTRICAL] charges. (40)

Front 490

1. Just as the positive pole of a magnet is attracted to the negative pole of another, so an atom can form a strong link with another atom if they have opposite electrical charges. Because an atom with an electrical charge is an ion, these bonds are called _____ _____. (40)

Back 490

Just as the positive pole of a magnet is attracted to the negative pole of another, so an atom can form a strong link with another atom if they have opposite electrical charges. Because an atom with an electrical charge is an ion, these bonds are called [IONIC BONDS]. (40)

Front 491

1. Everyday table salt is built of ionic bonds. The sodium and chlorine atoms of table salt are ____. (40)

Back 491

Everyday table salt is built of ionic bonds. The sodium and chlorine atoms of table salt are [IONS]. (40)

Front 492

1. Recall from section 2.1 that an atom is more stable when its outermost shell electron shell is filled (with ___ electrons in the innermost shell or _____ electrons in shells that are farther out from the nucleus). (40)

Back 492

Recall from section 2.1 that an atom is more stable when its outermost shell electron shell is filled (with [TWO] electrons in the innermost shell or [EIGHT] electrons in shells that are farther out from the nucleus). (40)

Front 493

1. To achieve this stability, an atom will give up or accept electrons from another ____. As a result of this electron hopping, sodium atoms in table salt are positive sodium ions and chlorine atoms are negative chloride ions. (40)

Back 493

To achieve this stability, an atom will give up or accept electrons from another [ATOM]. As a result of this electron hopping, sodium atoms in table salt are positive sodium ions and chlorine atoms are negative chloride ions. (40)

Front 494

1. Because each ion is attracted electrically to all surrounding ions of ________ charge, this causes the formation of an elaborate matrix of sodium and chloride ionic bonds – a crystal. The sodium chloride crystal reveals an organized structure of alternating sodium (yellow) and chloride (light green) ions. That is why table salt is composed of tiny crystals and is not a powder. (40)

Back 494

Because each ion is attracted electrically to all surrounding ions of [OPPOSITE] charge, this causes the formation of an elaborate matrix of sodium and chloride ionic bonds – a crystal. The sodium chloride crystal shown above reveals an organized structure of alternating sodium (yellow) and chloride (light green) ions. That is why table salt is composed of tiny crystals and is not a powder. (40)

Front 495

1. The two key properties of ionic bonds that make them form crystals are that they are strong (although not as strong as covalent bonds) and that they are not ___________. (40)

Back 495

The two key properties of ionic bonds that make them form crystals are that they are strong (although not as strong as covalent bonds) and that they are not [DIRECTIONAL]. (40)

Front 496

1. A charged atom is attracted to the __________ _____ contributed by all nearby atoms of opposite charge. Ionic bonds do not play an important part in most biological molecules because of this lack of directionality. Complex, stable shapes require the more specific associations made possible by directional bonds. (40)

Back 496

A charged atom is attracted to the [ELECTRICAL FIELD] contributed by all nearby atoms of opposite charge. Ionic bonds do not play an important part in most biological molecules because of this lack of directionality. Complex, stable shapes require the more specific associations made possible by directional bonds. (40)

Front 497

1. Strong chemical bonds called covalent bonds form between two atoms when they _____ electrons. Most of the atoms in your body are linked to other atoms by covalent bonds. (41)

Back 497

Strong chemical bonds called covalent bonds form between two atoms when they [SHARE] electrons. Most of the atoms in your body are linked to other atoms by covalent bonds. (41)

Front 498

1. Whey do atoms in molecules share electrons? Remember, all atoms seek to fill up their outermost shell of orbiting electrons, which in all atoms (except tiny hydrogen and helium) takes _____ electrons. (41)

Back 498

Whey do atoms in molecules share electrons? Remember, all atoms seek to fill up their outermost shell of orbiting electrons, which in all atoms (except tiny hydrogen and helium) takes [EIGHT] electrons. (41)

Front 499

1. A covalent bond is formed when electrons are shared between atoms. The atoms sharing the electrons may be of the same or different ________. Some atoms, like hydrogen (H), can form only one covalent bond, because hydrogen needs only one more electron to fill its outermost shell. (41)

Back 499

A covalent bond is formed when electrons are shared between atoms. The atoms sharing the electrons may be of the same or different [ELEMENTS]. Some atoms, like hydrogen (H), can form only one covalent bond, because hydrogen needs only one more electron to fill its outermost shell. (41)

Front 500

1. Other atoms, such as carbon (C), nitrogen (N), and oxygen (O), can form more than one covalent bond, depending on the space available in their _________ electron shells. (41)

Back 500

Other atoms, such as carbon (C), nitrogen (N), and oxygen (O), can form more than one covalent bond, depending on the space available in their [OUTERMOST] electron shells. (41)

Front 501

1. Most covalent bonds are ______ bonds, which involve the sharing of two electrons, but ______ bonds (in which four electrons are shared) are also common. ______ bonds (in which six electrons are shared) are much less frequent in nature but are found in some common compounds, like nitrogen gas (N2). (41)

Back 501

Most covalent bonds are [SINGLE] bonds, which involve the sharing of two electrons, but [DOUBLE] bonds (in which four electrons are shared) are also common. [TRIPLE] bonds (in which six electrons are shared) are much less frequent in nature but are found in some common compounds, like nitrogen gas (N2). (41)

Front 502

1. ______ is often released when covalent bonds are broken. The Hindenburg dirigible was filled with hydrogen gas when it exploded and burned in 1937; the energy of the inferno came from the breaking of H2 covalent bonds. (41)

Back 502

[ENERGY] is often released when covalent bonds are broken. The Hindenburg dirigible was filled with hydrogen gas when it exploded and burned in 1937; the energy of the inferno came from the breaking of H2 covalent bonds. (41)

Front 503

1. When a covalent bond forms between two atoms, one nucleus may be much better at __________ the shared electrons than the other, an aspect of the atom called its electronegativity. (41)

Back 503

When a covalent bond forms between two atoms, one nucleus may be much better at [ATTRACTING] the shared electrons than the other, an aspect of the atom called its electronegativity. (41)

Front 504

1. In water the shared electrons are much more strongly attracted to the oxygen atom than to the hydrogen atoms; oxygen has higher electronegativity. When this happens, shared electrons spend more time in the vicinity of the oxygen atom, which as a result becomes somewhat negative in charge; they spend less time in the vicinity of the hydrogens, and these become somewhat positive in charge. The charges are not full electrical charges like in ions but rather tiny partial charges signified by the Greek letter delta (𝛿). What you end up with is a sort of molecular magnet, with positive and negative ends, or “poles.” Molecules like this are said to be polar molecules, and the bonds between the atoms are called polar covalent bonds. (41)

Back 504

In water the shared electrons are much more strongly attracted to the oxygen atom than to the hydrogen atoms; oxygen has higher electronegativity. When this happens, shared electrons spend more time in the vicinity of the oxygen atom, which as a result becomes somewhat negative in charge; they spend less time in the vicinity of the hydrogens, and these become somewhat positive in charge. The charges are not full electrical charges like in ions but rather tiny partial charges signified by the Greek letter delta (𝛿). What you end up with is a sort of molecular magnet, with positive and negative ends, or “poles.” Molecules like this are said to be polar molecules, and the bonds between the atoms are called polar covalent bonds. (41)

Front 505

1. Molecules that don’t exhibit a large difference in ___________________ of its atoms, like the carbon-hydrogen bonds of methane, are called nonpolar molecules and contain nonpolar covalent bonds. (41)

Back 505

Molecules that don’t exhibit a large difference in [ELECTRONEGATIVITIES] of its atoms, like the carbon-hydrogen bonds of methane, are called nonpolar molecules and contain nonpolar covalent bonds. (41)

Front 506

1. The two key properties of covalent bonds that make them ideal for their molecule-building role in living systems are that (1) they are ______, involving the sharing of lots of energy; and (2) they are very ___________ – bonds form between two specific atoms, rather than a generalized attraction of one atom for its neighbors. (41)

Back 506

The two key properties of covalent bonds that make them ideal for their molecule-building role in living systems are that (1) they are [STRONG], involving the sharing of lots of energy; and (2) they are very [DIRECTIONAL] – bonds form between two specific atoms, rather than a generalized attraction of one atom for its neighbors. (41)

Front 507

1. Polar molecules like water are attracted to one another, a special type of weak chemical bond called a hydrogen bond. Hydrogen bonds occur when the ________ end of one polar molecule is attracted to the ________ end of another, like two magnets drawn to each other. (42)

Back 507

Polar molecules like water are attracted to one another, a special type of weak chemical bond called a hydrogen bond. Hydrogen bonds occur when the [POSITIVE] end of one polar molecule is attracted to the [NEGATIVE] end of another, like two magnets drawn to each other. (42)

Front 508

1. In a hydrogen bond, an _______________ hydrogen from one polar molecule is attracted to an _______________ atom, often oxygen (O) or nitrogen (N), from another polar molecule. (42)

Back 508

In a hydrogen bond, an [ELECTROPOSITIVE] hydrogen from one polar molecule is attracted to an [ELECTRONEGATIVE] atom, often oxygen (O) or nitrogen (N), from another polar molecule. (42)

Front 509

1. Because the oxygen atoms in water molecules are more electronegative than the hydrogen atoms, water molecules are _____. Water molecules form ______ hydrogen bonds with each other, giving liquid water many unique properties. (42)

Back 509

Because the oxygen atoms in water molecules are more electronegative than the hydrogen atoms, water molecules are [POLAR]. Water molecules form [STRONG] hydrogen bonds with each other, giving liquid water many unique properties. (42)

Front 510

1. Each oxygen has a partial negative charge (𝛿-), and each hydrogen has a partial positive charge (𝛿+). ________ _____ (shown as dashed lines) form between the positive end of one polar molecule and the negative end of another polar molecule. This attraction of partial charges attracts water molecules to one another. (42)

Back 510

Each oxygen has a partial negative charge (𝛿-), and each hydrogen has a partial positive charge (𝛿+). [HYDROGEN BONDS] (shown as dashed lines) form between the positive end of one polar molecule and the negative end of another polar molecule. This attraction of partial charges attracts water molecules to one another. (42)

Front 511

1. Two key properties of hydrogen bonds cause them to play an important role in the molecules found in organisms. First, they are ____ and so are not effective over long distances like more powerful covalent and ionic bonds. Hydrogen bonds are too weak to actually form stable molecules by themselves. Instead, they act like Velcro, forming a tight bond by the additive effects of many weak interactions. Second, hydrogen bonds are highly ___________. (42)

Back 511

Two key properties of hydrogen bonds cause them to play an important role in the molecules found in organisms. First, they are [WEAK] and so are not effective over long distances like more powerful covalent and ionic bonds. Hydrogen bonds are too weak to actually form stable molecules by themselves. Instead, they act like Velcro, forming a tight bond by the additive effects of many weak interactions. Second, hydrogen bonds are highly [DIRECTIONAL]. (42)

Front 512

1. Another important kind of weak chemical attraction is a ___-___________ attractive force called van der Waals forces (or van der Waals interactions). These chemical forces come into play only when two atoms are very _____ to one another. The attraction is very weak and disappears if the atoms move even a little apart. It becomes significant when numerous atoms in one molecule simultaneously come close to numerous atoms of another molecule – that is, when the shapes of the molecules match precisely. For example, this interaction is important when antibodies in your blood recognize the shape of an invading virus as foreign. (42)

Back 512

Another important kind of weak chemical attraction is a [NON-DIRECTIONAL] attractive force called van der Waals forces (or van der Waals interactions). These chemical forces come into play only when two atoms are very [CLOSE] to one another. The attraction is very weak and disappears if the atoms move even a little apart. It becomes significant when numerous atoms in one molecule simultaneously come close to numerous atoms of another molecule – that is, when the shapes of the molecules match precisely. For example, this interaction is important when antibodies in your blood recognize the shape of an invading virus as foreign. (42)

Front 513

1. Key Learning Outcome 2.3 – Molecules are atoms ______ together by chemical bonds. Ionic bonds, covalent bonds, and hydrogen bonds are the three _________ types of bonds, and van der Waals forces are weaker interactions. (42)

Back 513

Key Learning Outcome 2.3 – Molecules are atoms [LINKED] together by chemical bonds. Ionic bonds, covalent bonds, and hydrogen bonds are the three [PRINCIPAL] types of bonds, and van der Waals forces are weaker interactions. (42)

Front 514

1. Water has a simple ______ structure, an oxygen atom linked to two hydrogen atoms by single ________ bonds. The chemical formula for water is thus H20. (43)

Back 514

Water has a simple [ATOMIC] structure, an oxygen atom linked to two hydrogen atoms by single [COVALENT] bonds. The chemical formula for water is thus H20. (43)

Front 515

1. It is because the oxygen atom attracts the shared electrons more strongly than the hydrogen atoms that water is a _____ molecule and so can form hydrogen bonds. Water’s ability to form hydrogen bonds is responsible for much of the organization of living chemistry, from membrane structure to how proteins fold. (43)

Back 515

It is because the oxygen atom attracts the shared electrons more strongly than the hydrogen atoms that water is a [POLAR] molecule and so can form hydrogen bonds. Water’s ability to form hydrogen bonds is responsible for much of the organization of living chemistry, from membrane structure to how proteins fold. (43)

Front 516

1. The ____ hydrogen bonds that form between a hydrogen atom of one water molecule and the oxygen atom of another produce a lattice of hydrogen bonds within liquid water. Each of these bonds is individually very weak and short-lived – a single bond lasts only 1/100,000,000,000 of a second. However, like the grains of sand on a beach, the cumulative effect of large numbers of these bonds is enormous and is responsible for many of the important physical properties of water (table 2.2). (43)

Back 516

The [WEAK] hydrogen bonds that form between a hydrogen atom of one water molecule and the oxygen atom of another produce a lattice of hydrogen bonds within liquid water. Each of these bonds is individually very weak and short-lived – a single bond lasts only 1/100,000,000,000 of a second. However, like the grains of sand on a beach, the cumulative effect of large numbers of these bonds is enormous and is responsible for many of the important physical properties of water (table 2.2). (43)

Front 517

1. The temperature of any substance is a measure of how rapidly its individual _________ are moving. (43)

Back 517

The temperature of any substance is a measure of how rapidly its individual [MOLECULES] are moving. (43)

Front 518

1. Because of the many hydrogen bonds that water molecules form with one another, a large input of _______ ______ is required to disrupt the organization of liquid water and raise its temperature. Because of this, water heats up more slowly than almost any other compound and holds its temperature ______. That is a major reason why your body is able to maintain a relatively constant internal temperature. (43)

Back 518

Because of the many hydrogen bonds that water molecules form with one another, a large input of [THERMAL ENERGY] is required to disrupt the organization of liquid water and raise its temperature. Because of this, water heats up more slowly than almost any other compound and holds its temperature [LONGER]. That is a major reason why your body is able to maintain a relatively constant internal temperature. (43)

Front 519

1. If the temperature is low enough, very few hydrogen bonds _____ in water. Instead, the lattice of these bonds assumes a crystal-like structure, forming a solid we call ice. Interestingly, ice is less dense than water – that is why icebergs and ice cubes float. Why is ice less dense? This is best understood by comparing the molecular structures of water and ice that you see in figure 2.9. At temperature above freezing (0˚C or 32˚F), water molecules in figure 2.9a move around each other with hydrogen bonds breaking and forming. As temperatures drop, the movement of water molecules decreases, allowing hydrogen bonds to _________, holding individual molecules farther apart, as in figure 2.9b, making the ice structure less dense. (43)

Back 519

If the temperature is low enough, very few hydrogen bonds [BREAK] in water. Instead, the lattice of these bonds assumes a crystal-like structure, forming a solid we call ice. Interestingly, ice is less dense than water – that is why icebergs and ice cubes float. Why is ice less dense? This is best understood by comparing the molecular structures of water and ice that you see in figure 2.9. At temperature above freezing (0˚C or 32˚F), water molecules in figure 2.9a move around each other with hydrogen bonds breaking and forming. As temperatures drop, the movement of water molecules decreases, allowing hydrogen bonds to [STABILIZE], holding individual molecules farther apart, as in figure 2.9b, making the ice structure less dense. (43)

Front 520

1. Figure 2.9 – Ice Formation. When water (a) cools below 0˚C, it forms a regular crystal structure (b) that floats. The individual water molecules are ______ apart and held in position by hydrogen bonds. (43)

Back 520

Figure 2.9 – Ice Formation. When water (a) cools below 0˚C, it forms a regular crystal structure (b) that floats. The individual water molecules are [SPACED] apart and held in position by hydrogen bonds. (43)

Front 521

1. If the temperature is high enough, many hydrogen bonds _____ in water, with the result that the liquid is changed into vapor. A considerable amount of heat energy is required to do this – every gram of water that evaporates from your skin removes 2,452 joules of heat from your body, which is equal to the energy released by ________ the temperature of 586 grams of water 1˚C. That is why sweating cools you off; as the sweat evaporates (vaporizes) it takes energy with it, in the form of heat, cooling the body. (43)

Back 521

If the temperature is high enough, many hydrogen bonds [BREAK] in water, with the result that the liquid is changed into vapor. A considerable amount of heat energy is required to do this – every gram of water that evaporates from your skin removes 2,452 joules of heat from your body, which is equal to the energy released by [LOWERING] the temperature of 586 grams of water 1˚C. That is why sweating cools you off; as the sweat evaporates (vaporizes) it takes energy with it, in the form of heat, cooling the body. (43)

Front 522

1. Because water molecules are very polar, they are attracted to other polar molecules – ________ bonds bind polar molecules to each other. (44)

Back 522

Because water molecules are very polar, they are attracted to other polar molecules – [HYDROGEN] bonds bind polar molecules to each other. (44)

Front 523

1. When the other polar molecule is another water molecule, the attraction is called ________. (44)

Back 523

When the other polar molecule is another water molecule, the attraction is called [COHESION]. (44)

Front 524

1. The surface tension of water is created by cohesion. Surface tension is the _____ that causes water to bead, like on the spider web in figure 2.10, or supports the weight of the water strider. (44)

Back 524

The surface tension of water is created by cohesion. Surface tension is the [FORCE] that causes water to bead, like on the spider web in figure 2.10, or supports the weight of the water strider. (44)

Front 525

1. When the other polar molecule is a different substance, the attraction is called ________. (44)

Back 525

When the other polar molecule is a different substance, the attraction is called [ADHESION]. (44)

Front 526

1. Capillary action – such as water moving up into a paper towel – is created by adhesion. Water clings to any substance, such as paper fibers, with which it can form ________ bonds. Adhesion is why things get “wet” when they are dipped in water and why waxy substances do not – they are composed of ________ molecules that don’t form hydrogen bonds with water molecules. (44)

Back 526

Capillary action – such as water moving up into a paper towel – is created by adhesion. Water clings to any substance, such as paper fibers, with which it can form [HYDROGEN] bonds. Adhesion is why things get “wet” when they are dipped in water and why waxy substances do not – they are composed of [NONPOLAR] molecules that don’t form hydrogen bonds with water molecules. (44)

Front 527

1. Figure 2.10 – Cohesion. (a) Cohesion allows water molecules to _____ together and form droplets. (b) _______ _______ is a property derived from cohesion – that is, water has a “strong” surface due to the force of its hydrogen bonds. Some insects, such as this water strider, literally walk on water. (44)

Back 527

Figure 2.10 – Cohesion. (a) Cohesion allows water molecules to [STICK] together and form droplets. (b) [SURFACE TENSION] is a property derived from cohesion – that is, water has a “strong” surface due to the force of its hydrogen bonds. Some insects, such as this water strider, literally walk on water. (44)

Front 528

1. Water molecules in solution always tend to form the _______ number of hydrogen bonds possible. (44)

Back 528

Water molecules in solution always tend to form the [MAXIMUM] number of hydrogen bonds possible. (44)

Front 529

1. _____ molecules form hydrogen bonds and are attracted to water molecules. (44)

Back 529

[POLAR] molecules form hydrogen bonds and are attracted to water molecules. (44)

Front 530

1. Polar molecules are called hydrophilic (from the Greek hydros, water, and philic, loving), or water-loving, molecules. Water molecules gather closely around any molecule that exhibits an electrical charge, whether a full charge (___) or partial charge (_____ molecule). (44)

Back 530

Polar molecules are called hydrophilic (from the Greek hydros, water, and philic, loving), or water-loving, molecules. Water molecules gather closely around any molecule that exhibits an electrical charge, whether a full charge (ION) or partial charge ([POLAR] molecule). (44)

Front 531

1. When a salt crystal dissolves in water as you see happening in figure 2.11, what really happens is that individual ____ break off from the crystal and become surrounded by water molecules. The blue hydrogen atoms of water are attracted to the negative charge of the chloride ions, and the red oxygen atoms are attracted to the positive charge of the sodium ions. Water molecules orient around each ion like a swarm of bees attracted to honey, and this shell of water molecules, called a _________ _____, prevents the ion from reassociating with the crystal. Similar shells of water form around all polar molecules, and polar molecules that dissolve in water in this way are said to be _______ in water. (44)

Back 531

When a salt crystal dissolves in water as you see happening in figure 2.11, what really happens is that individual [IONS] break off from the crystal and become surrounded by water molecules. The blue hydrogen atoms of water are attracted to the negative charge of the chloride ions, and the red oxygen atoms are attracted to the positive charge of the sodium ions. Water molecules orient around each ion like a swarm of bees attracted to honey, and this shell of water molecules, called a [HYDRATION SHELL], prevents the ion from reassociating with the crystal. Similar shells of water form around all polar molecules, and polar molecules that dissolve in water in this way are said to be [SOLUBLE] in water. (44)

Front 532

1. Nonpolar molecules like oil do not form hydrogen bonds and are not _____-_______. When nonpolar molecules are placed in water, the water molecules shy away, instead forming hydrogen bonds with other water molecules. The nonpolar molecules are forced into association with one another, crowded together to minimize their disruption of the hydrogen bonding of water. (44)

Back 532

Nonpolar molecules like oil do not form hydrogen bonds and are not [WATER-SOLUBLE]. When nonpolar molecules are placed in water, the water molecules shy away, instead forming hydrogen bonds with other water molecules. The nonpolar molecules are forced into association with one another, crowded together to minimize their disruption of the hydrogen bonding of water. (44)

Front 533

1. It seems almost as if the ________ compounds shrink from contact with water, and for this reason they are called hydrophobic (from the Greek hydros, water, and phobos, fearing). Many biological structures are shaped by such hydrophobic forces. (44)

Back 533

It seems almost as if the [NONPOLAR] compounds shrink from contact with water, and for this reason they are called hydrophobic (from the Greek hydros, water, and phobos, fearing). Many biological structures are shaped by such hydrophobic forces. (44)

Front 534

1. Figure 2.11 – How salt dissolves in water. Salt is _______ in water because the partial charges on water molecules are attracted to the charged sodium and chloride ions. The water molecules surround the ions, forming what are called _________ ______. When all of the ions have been separated from the crystal, the salt is aid to be dissolved. (44)

Back 534

Figure 2.11 – How salt dissolves in water. Salt is [SOLUBLE] in water because the partial charges on water molecules are attracted to the charged sodium and chloride ions. The water molecules surround the ions, forming what are called [HYDRATION SHELLS]. When all of the ions have been separated from the crystal, the salt is aid to be dissolved. (44)

Front 535

1. Key Learning Outcome 2.4 – Water molecules form a network of hydrogen bonds in liquid and dissolve other _____ _________. Many of the key properties of water arise because it takes considerable ______ to break liquid water’s many hydrogen bonds. (44)

Back 535

Key Learning Outcome 2.4 – Water molecules form a network of hydrogen bonds in liquid and dissolve other [POLAR MOLECULES]. Many of the key properties of water arise because it takes considerable [ENERGY] to break liquid water’s many hydrogen bonds. (44)

Front 536

1. The ________ _____ within a water molecule sometimes break spontaneously. When it happens, a proton (hydrogen atom nucleus) dissociates from the molecule. Because the dissociated proton lacks the negatively charged electron it was sharing in the covalent bond with oxygen, its own positive charge is no longer counterbalanced, and it becomes a positively charged ion, hydrogen ion (H+). The rest of the dissociated water molecule, which has retained the shared electron from the covalent bond, is negatively charged and forms a hydroxide ion (OH-). This process of spontaneous ion formation is called __________. It can be represented by a simple chemical equation in which the chemical formulas for water and the two ions are written down with an arrow showing the direction of the dissociation: H20 (water)

Back 536

The [COVALENT BONDS ]within a water molecule sometimes break spontaneously. When it happens, a proton (hydrogen atom nucleus) dissociates from the molecule. Because the dissociated proton lacks the negatively charged electron it was sharing in the covalent bond with oxygen, its own positive charge is no longer counterbalanced, and it becomes a positively charged ion, hydrogen ion (H+). The rest of the dissociated water molecule, which has retained the shared electron from the covalent bond, is negatively charged and forms a hydroxide ion (OH-). This process of spontaneous ion formation is called [IONIZATION]. It can be represented by a simple chemical equation in which the chemical formulas for water and the two ions are written down with an arrow showing the direction of the dissociation:

H20 (water) OH- (hydroxide ion) + H+ (hydrogen ion) (45)

Hint 536

The [COVALENT BONDS ]within a water molecule sometimes break spontaneously. When it happens, a proton (hydrogen atom nucleus) dissociates from the molecule. Because the dissociated proton lacks the negatively charged electron it was sharing in the covalent bond with oxygen, its own positive charge is no longer counterbalanced, and it becomes a positively charged ion, hydrogen ion (H+). The rest of the dissociated water molecule, which has retained the shared electron from the covalent bond, is negatively charged and forms a hydroxide ion (OH-). This process of spontaneous ion formation is called [IONIZATION]. It can be represented by a simple chemical equation in which the chemical formulas for water and the two ions are written down with an arrow showing the direction of the dissociation: H20 (water)

Front 537

1. Because covalent bonds are ______, spontaneous ionization is not common, In a liter of water, only roughly 1 molecule out of each 550 million is ionized at any instant in time, corresponding to 1/10,000,000 (that is, 10-7) of a mole of hydrogen ions. (A mole is a measurement of weight. One mole of any object is the weight of 6,022x1023 units of that object.) The _____________ of H+ in water can be written more easily by simply counting the number of decimal place after the digit “1” in the denominator: [H+] = 1/10,000,000 (45)

Back 537

Because covalent bonds are [STRONG], spontaneous ionization is not common, In a liter of water, only roughly 1 molecule out of each 550 million is ionized at any instant in time, corresponding to 1/10,000,000 (that is, 10-7) of a mole of hydrogen ions. (A mole is a measurement of weight. One mole of any object is the weight of 6,022x1023 units of that object.) The [CONCENTRATION] of H+ in water can be written more easily by simply counting the number of decimal place after the digit “1” in the denominator: [H+] = 1/10,000,000 (45)

Front 538

1. A more convenient way to express the hydrogen ion concentration of a solution is to use the __ scale (figure 2.12). This scale defines __ as the negative logarithm of the hydrogen ion concentration in the solution: pH = -log [H+] (45)

Back 538

A more convenient way to express the hydrogen ion concentration of a solution is to use the [pH] scale (figure 2.12). This scale defines [pH] as the negative logarithm of the hydrogen ion concentration in the solution: pH = -log [H+] (45)

Front 539

1. Since the logarithm of the hydrogen ion concentration is simply the exponent of the molar concentration of H+, the pH equals the exponent time -1. Thus, pure water, with an [H+] of 10-7 mole/liter, has a pH of 7. Recall that for every hydrogen ion formed when water ___________, a hydroxide ion is also formed, meaning that the dissociation of water produces H+ and OH- in _____ amounts. Therefore, a pH value of 7 indicates neutrality – a balance between H+ and OH- - on the pH scale. (45)

Back 539

Since the logarithm of the hydrogen ion concentration is simply the exponent of the molar concentration of H+, the pH equals the exponent time -1. Thus, pure water, with an [H+] of 10-7 mole/liter, has a pH of 7. Recall that for every hydrogen ion formed when water [DISSOCIATES], a hydroxide ion is also formed, meaning that the dissociation of water produces H+ and OH- in [EQUAL] amounts. Therefore, a pH value of 7 indicates neutrality – a balance between H+ and OH- - on the pH scale. (45)

Front 540

1. Note that the pH scale is ___________, which means that a difference of 1 on the pH scale represents a 10-fold change in hydrogen ion concentration. This means that a solution with a pH of 4 has 10 times the concentration of H+ present in one with a pH of 5. (45)

Back 540

Note that the pH scale is [LOGARITHMIC], which means that a difference of 1 on the pH scale represents a 10-fold change in hydrogen ion concentration. This means that a solution with a pH of 4 has 10 times the concentration of H+ present in one with a pH of 5. (45)

Front 541

1. Any substance that dissociates in water to increase the concentration of H+ is called a(n) ____. (45)

Back 541

Any substance that dissociates in water to increase the concentration of H+ is called a(n) [ACID]. (45)

Front 542

1. ______ solutions have pH values below 7. (45)

Back 542

[ACIDIC] solutions have pH values below 7. (45)

Front 543

1. The ________ an acid is, the more H+ it produces and the lower its pH. The pH of champagne, which bubbles because of the carbonic acid dissolved in it, is about 3. (45)

Back 543

The [STRONGER] an acid is, the more H+ it produces and the lower its pH. The pH of champagne, which bubbles because of the carbonic acid dissolved in it, is about 3. (45)

Front 544

1. A substance that combines with H+ when dissolved in water is called a ____. (45)

Back 544

A substance that combines with H+ when dissolved in water is called a [BASE]. (45)

Front 545

1. By combining with H+, a base lowers the H+ concentration in the solution. Basic (or ________) solutions, therefore, have pH values above 7. (45)

Back 545

By combining with H+, a base lowers the H+ concentration in the solution. Basic (or [ALKALINE]) solutions, therefore, have pH values above 7. (45)

Front 546

1. Very strong bases, such as sodium hydroxide (NaOH), have pH values of __ or more. (45)

Back 546

Very strong bases, such as sodium hydroxide (NaOH), have pH values of [12] or more. (45)

Front 547

1. The pH inside almost all living cells, and in the fluid surrounding cells in multicellular organisms, is fairly close to _. (47)

Back 547

The pH inside almost all living cells, and in the fluid surrounding cells in multicellular organisms, is fairly close to [7]. (47)

Front 548

1. The many ________ that govern metabolism are all extremely sensitive to pH, and slight alterations in pH can cause the molecules to take on different shapes that disrupt their activities. For this reason, it is important that a cell maintain a ________ pH level. (47)

Back 548

The many [PROTEINS] that govern metabolism are all extremely sensitive to pH, and slight alterations in pH can cause the molecules to take on different shapes that disrupt their activities. For this reason, it is important that a cell maintain a [CONSTANT] pH level. (47)

Front 549

1. The pH of your blood, for example, is 7.4, and you would survive only a few minutes if it were to fall to _._ or rise to _._. (47)

Back 549

The pH of your blood, for example, is 7.4, and you would survive only a few minutes if it were to fall to [7.0] or rise to [7.8]. (47)

Front 550

1. The chemical reactions of life constantly produce _____ and _____ within cells. Many animals eat substances that are acidic or basic; Coca-Cola, for example, is acidic, and egg white is basic. (47)

Back 550

The chemical reactions of life constantly produce [ACIDS] and [BASES] within cells. Many animals eat substances that are acidic or basic; Coca-Cola, for example, is acidic, and egg white is basic. (47)

Front 551

1. What keeps an organism’s pH constant? Cells contain chemical substances called _______ that minimize changes in concentrations of H+ and OH-. (47)

Back 551

What keeps an organism’s pH constant? Cells contain chemical substances called [BUFFERS] that minimize changes in concentrations of H+ and OH-. (47)

Front 552

1. A buffer is a substance that takes up or releases hydrogen ions into solution as the hydrogen ion concentration of the solution changes. Hydrogen ions are _______ to the solution when their concentration falls and _____ from the solution when their concentration rises. (47)

Back 552

A buffer is a substance that takes up or releases hydrogen ions into solution as the hydrogen ion concentration of the solution changes. Hydrogen ions are [DONATED] to the solution when their concentration falls and [TAKEN] from the solution when their concentration rises. (47)

Front 553

1. The graph in figure 2.13 shows how buffers work. The blue line indicates changes in pH. As a base is added to the solution, the H+ concentration _____ and the pH should ____ sharply, but by contributing H+ to the solution, the buffer works to keep the pH within a range, called the buffering range (the darker blue bar). Only when the buffering capacity is exceeded does the pH begin to rise. What sort of substance will act in this way? Within organisms, most buffers consist of pairs of substances, one an acid and the other a base. (47)

Back 553

The graph in figure 2.13 shows how buffers work. The blue line indicates changes in pH. As a base is added to the solution, the H+ concentration [FALLS] and the pH should [RISE] sharply, but by contributing H+ to the solution, the buffer works to keep the pH within a range, called the buffering range (the darker blue bar). Only when the buffering capacity is exceeded does the pH begin to rise. What sort of substance will act in this way? Within organisms, most buffers consist of pairs of substances, one an acid and the other a base. (47)

Front 554

1. The key buffer in human blood is an ____-____ pair consisting of carbonic acid (acid) and bicarbonate (base). These two substances interact in a pair of reversible reactions. First, carbon dioxide (CO2) and H2O join to form carbonic acid (H2CO3) (step 2 in figure 2.14), which in a second reaction dissociates to yield bicarbonate ion (HCO3-) and H+ (step 3). If some acid or other substance adds H+ to the blood, the HCO3- acts as a base and removes the excess H+ by forming H2CO3. Similarly, if a basic substance removes H+ from the blood, H2CO3 dissociates, releasing more H+ into the blood. The forward and reverse reactions that interconvert H2CO3 and HCO3- thus _________ the blood’s pH. (47)

Back 554

The key buffer in human blood is an [ACID-BASE] pair consisting of carbonic acid (acid) and bicarbonate (base). These two substances interact in a pair of reversible reactions. First, carbon dioxide (CO2) and H2O join to form carbonic acid (H2CO3) (step 2 in figure 2.14), which in a second reaction dissociates to yield bicarbonate ion (HCO3-) and H+ (step 3). If some acid or other substance adds H+ to the blood, the HCO3- acts as a base and removes the excess H+ by forming H2CO3. Similarly, if a basic substance removes H+ from the blood, H2CO3 dissociates, releasing more H+ into the blood. The forward and reverse reactions that interconvert H2CO3 and HCO3- thus [STABILIZE] the blood’s pH. (47)

Front 555

1. When you breathe in, your body takes up oxygen from the air and when you breathe out, your body releases carbon dioxide. When you hold your breath, CO2 releases carbon dioxide. When you hold your breath, CO2 accumulates in your blood and drives the chemical reactions in figure 2.14, producing carbonic acid. Can you hold your breath indefinitely? No, but not for the reason you might think. It is not lack of oxygen that forces you to breathe but too much carbon dioxide. If you try to hold your breath for very long, CO2 accumulates in the blood, as shown in step 1 in figure 2.14, triggering the formation of carbonic acid (step 2) that dissociates into bicarbonate ion and H+ (step 3). This increase in H+ causes the blood to become more acidic. If the pH in the blood drops too low, pH sensors that are located in some of the major blood vessels of the body detect the change (step 4) and send signals to the brain. These signals, along with other sensory processes, stimulate the area of the brain that controls respiration, causing it to increase the rate of breathing. Hyperventilating, breathing very quickly, has the opposite effect, lowering the levels of CO2 in the blood. That is why you are told to breathe into a paper bag when you are hyperventilating, to increase your intake of CO2. (47)

Back 555

When you breathe in, your body takes up oxygen from the air and when you breathe out, your body releases carbon dioxide. When you hold your breath, CO2 releases carbon dioxide. When you hold your breath, CO2 accumulates in your blood and drives the chemical reactions in figure 2.14, producing carbonic acid. Can you hold your breath indefinitely? No, but not for the reason you might think. It is not lack of oxygen that forces you to breathe but too much carbon dioxide. If you try to hold your breath for very long, CO2 accumulates in the blood, as shown in step 1 in figure 2.14, triggering the formation of carbonic acid (step 2) that dissociates into bicarbonate ion and H+ (step 3). This increase in H+ causes the blood to become more acidic. If the pH in the blood drops too low, pH sensors that are located in some of the major blood vessels of the body detect the change (step 4) and send signals to the brain. These signals, along with other sensory processes, stimulate the area of the brain that controls respiration, causing it to increase the rate of breathing. Hyperventilating, breathing very quickly, has the opposite effect, lowering the levels of CO2 in the blood. That is why you are told to breathe into a paper bag when you are hyperventilating, to increase your intake of CO2. (47)

Front 556

1. Key Learning Outcome 2.5 – A tiny fraction of water molecules spontaneously ionize at any moment, forming H+ and OH-. The pH of a solution is a measure of its H+ concentration. Low pH of a solution is a measure of its H+ concentration. Low pH values indicate high H+ concentration (______ solutions), and high pH values indicate low H+ concentrations (_____ solutions). (47)

Back 556

Key Learning Outcome 2.5 – A tiny fraction of water molecules spontaneously ionize at any moment, forming H+ and OH-. The pH of a solution is a measure of its H+ concentration. Low pH of a solution is a measure of its H+ concentration. Low pH values indicate high H+ concentration ([ACIDIC] solutions), and high pH values indicate low H+ concentrations ([BASIC] solutions). (47)

Front 557

1. Figure 2.13 – Buffers minimize changes in pH. Adding a ____ to a solution neutralizes some of the acid present and so raises the pH. Thus, as the curve moves to the right, reflecting more and more base, it also rises to higher pH values. What a buffer does is to make the curve rise or fall very slowly over a portion of the pH scale, called the “_________ _____” of that buffer. (47)

Back 557

Figure 2.13 – Buffers minimize changes in pH. Adding a [BASE] to a solution neutralizes some of the acid present and so raises the pH. Thus, as the curve moves to the right, reflecting more and more base, it also rises to higher pH values. What a buffer does is to make the curve rise or fall very slowly over a portion of the pH scale, called the “[BUFFERING RANGE]” of that buffer. (47)

Front 558

1. Figure 2.14 – Holding your breath. CO2 accumulates in the blood when a person holds his or her breath. CO2 combines with water, forming carbonic acid. Carbonic acid dissociates into bicarbonate and H+, which acts to lower the pH. The drop in pH is detected by sensors that stimulate the brain, causing the person to _______. (47)

Back 558

Figure 2.14 – Holding your breath. CO2 accumulates in the blood when a person holds his or her breath. CO2 combines with water, forming carbonic acid. Carbonic acid dissociates into bicarbonate and H+, which acts to lower the pH. The drop in pH is detected by sensors that stimulate the brain, causing the person to [BREATHE]. (47)

Front 559

1. In the fall of 1991, sticking out of the melting snow on the crest of a high pass near the mountainous border between Italy and Austria, two Austrian hikers found a corpse. Right away it was clear the body was very old, frozen in an icy trench where he has sought shelter long ago and only now released as the ice melted. In the years since this startling find, scientists have learned a great deal about the dead man, whom they named Otzi. They know his age, his health, the shoes and clothing he wore, what he ate, and that he died from an arrow that ripped through his back. Its tip is still embedded in the back of his left shoulder. From the distribution of chemicals in his teeth and bones, we know he lived his life within 60 kilometers of where he died.

Back 559

How long ago did this Iceman die? Scientists answered this key question by measuring the degree of decay of the short-lived carbon isotope 14C in Otzi’s body. This procedure is discussed earlier in this chapter (see figure 2.8). The graph to the right displays the radioactive decay curve of the carbon isotope carbon-14 (14C); it takes 5,730 years for half of the 14C present in a sample to decay to nitrogen-14 (14N). When Otzi’s carbon isotopes were analyzed, researchers determined that the ratio of 14C to 12C (a ratio is the size of one variable relative to another), also written as the fraction 14C/12C, in Otzi’s body is 0.435 of the fraction found in tissues of a person who has recently died. (48)

Front 560

1. Applying Concepts. A. Variable. In the graph, what is the dependent variable? (48)

Back 560

1. Applying Concepts. A. Variable. In the graph, what is the dependent variable? (48)

Front 561

1. Applying Concepts. B. Proportion. What proportion (a proportion is the size of a variable relative to the whole) of the 14C present in Otzi’s body when he died is still there today? (48)

Back 561

1. Applying Concepts. B. Proportion. What proportion (a proportion is the size of a variable relative to the whole) of the 14C present in Otzi’s body when he died is still there today? (48)

Front 562

1. Interpreting Data. Plot this proportion on the 14C radioactive decay curve above. How many half-lives does this point represent? (48)

Back 562

1. Interpreting Data. Plot this proportion on the 14C radioactive decay curve above. How many half-lives does this point represent? (48)

Front 563

1. Making Inferences. If Otzi were indeed a recent corpse, made to look old by the harsh weather conditions found on the high mountain pass, what would you expect the ratio of 14C to 12C to be, relative to that in your own body? (48)

Back 563

1. Making Inferences. If Otzi were indeed a recent corpse, made to look old by the harsh weather conditions found on the high mountain pass, what would you expect the ratio of 14C to 12C to be, relative to that in your own body? (48)

Front 564

1. Drawing Conclusions. How old are the remains of the Iceman Otzi? (48)

Back 564

1. Drawing Conclusions. How old are the remains of the Iceman Otzi? (48)

Front 565

1. Further Analysis. A. The radioactive iodine isotope 13I decays at a half-life of eight days. Plotted on the graph above, would its radioactive decay curve be above or below that of 14C? (48)

Back 565

1. Further Analysis. A. The radioactive iodine isotope 13I decays at a half-life of eight days. Plotted on the graph above, would its radioactive decay curve be above or below that of 14C? (48)

Front 566

1. Further Analysis B. Scientists often employ the radioactive decay of Isotope potassium-40 (40K) into argon-40 (40Ar) to date old material. 40K has a half-life of 1.3 billion years. Would it be a better isotope than 14C for dating Otzi? (48)

Back 566

1. Further Analysis B. Scientists often employ the radioactive decay of Isotope potassium-40 (40K) into argon-40 (40Ar) to date old material. 40K has a half-life of 1.3 billion years. Would it be a better isotope than 14C for dating Otzi? (48)

Front 567

2.1.1A An ____ is the smallest particle that retains the chemical properties of its substance. (49)

Back 567

2.1.1A An [ATOM] is the smallest particle that retains the chemical properties of its substance. (49)

Front 568

Atoms, like the carbon atom shown here from figure 2.2, contain a core nucleus of _______ and ________; _________ spin around the nucleus. (49)

Back 568

Atoms, like the carbon atom shown here from figure 2.2, contain a core nucleus of [PROTONS] and [NEUTRONS]; [ELECTRONS] spin around the nucleus. (49)

Front 569

The number of _________ equals the number of protons in a typical atom. (49)

Back 569

The number of [ELECTRONS] equals the number of protons in a typical atom. (49)

Front 570

2.1.1B The number of protons in an atom is called its atomic number. (49)

Back 570

2.1.1B The number of protons in an atom is called its [ATOMIC NUMBER]. (49)

Front 571

The mass that is contributed by the protons and neutrons is called the atom’s ____ ______. (49)

Back 571

The mass that is contributed by the protons and neutrons is called the atom’s [MASS NUMBER]. (49)

Front 572

All atoms that have the same ______ ______ are said to be the same element. (49)

Back 572

All atoms that have the same [ATOMIC NUMBER]atomic number are said to be the same element. (49)

Front 573

2.1.2A _______ are positively charged particles, and ________ carry no charge. (49)

Back 573

2.1.2A [PROTONS] are positively charged particles, and [NEUTRONS] carry no charge. (49)

Front 574

a

Back 574

a

Front 575

Electrons are __________ charged particles that orbit around the nucleus at different ______ levels. (49)

Back 575

Electrons are [NEGATIVELY] charged particles that orbit around the nucleus at different [ENERGY] levels. (49)

Front 576

_________ determine the chemical behavior of an atom because they are the subatomic particles that interact with other atoms. (49)

Back 576

[ELECTRONS] determine the chemical behavior of an atom because they are the subatomic particles that interact with other atoms. (49)

Front 577

2.1.2B It takes energy to hold electrons in their orbits; this energy of position is called _________ energy. (49)

Back 577

It takes energy to hold electrons in their orbits; this energy of position is called [POTENTIAL] energy. (49)

Front 578

The amount of potential energy of an electron is based on its ________ from the nucleus. (49)

Back 578

The amount of potential energy of an electron is based on its [DISTANCE] from the nucleus. (49)

Front 579

2.1.2C Most electron shells hold up to _____ electrons, and atoms will undergo ________ reactions in order to fill the outermost electron shell. (49)

Back 579

Most electron shells hold up to [EIGHT] electrons, and atoms will undergo [CHEMICAL] reactions in order to fill the outermost electron shell. (49)

Front 580

2.2.1 Ions are atoms that have either gained one or more electrons (________ ions called anions) or lost one or more electrons (________ ions called cations). (49)

Back 580

Ions are atoms that have either gained one or more electrons ([NEGATIVE] ions called anions) or lost one or more electrons ([POSITIVE] ions called cations). (49)

Front 581

2.2.2 Isotopes are atoms that have the same number of _______ but differing numbers of ________. (49)

Back 581

Isotopes are atoms that have the same number of [PROTONS] but differing numbers of [NEUTRONS]. (49)

Front 582

Isotopes tend to be unstable and break up into other elements through a process called ___________ _____. (49)

Back 582

Isotopes tend to be unstable and break up into other elements through a process called [RADIOACTIVE DECAY]. (49)

Front 583

2.2.3 Some ________ can be used in medicine and dating fossils. (49)

Back 583

Some [ISOTOPES] can be used in medicine and dating fossils. (49)

Front 584

2.3.1A Molecules are _____ linked together by chemical bonds. There are three main types of chemical bonds. (49)

Back 584

Molecules are [ATOMS] linked together by chemical bonds. There are three main types of chemical bonds. (49)

Front 585

2.3.1B _____ _____ form when ions of opposite charge are attracted to each other. Table salt is formed by _____ _____ between positive sodium ions and negative chloride ions. (49)

Back 585

[IONIC BONDS] form when ions of opposite charge are attracted to each other. Table salt is formed by [IONIC BONDS] between positive sodium ions and negative chloride ions. (49)

Front 586

2.3.2 Covalent bonds form when ___ atoms share electrons, attempting to fill empty electron orbitals (integrated are, page 41). Covalent bonds are ________ when more electrons are shared. (49)

Back 586

Covalent bonds form when [TWO] atoms share electrons, attempting to fill empty electron orbitals (integrated are, page 41). Covalent bonds are [STRONGER] when more electrons are shared. (49)

Front 587

2.3.3 The _____ in a polar molecule are held together by covalent bonds in which the shared electrons are ________ distributed around their nuclei, giving the molecule a slightly positive end and a slightly negative end. (49)

Back 587

The [ATOMS] in a polar molecule are held together by covalent bonds in which the shared electrons are [UNEVENLY] distributed around their nuclei, giving the molecule a slightly positive end and a slightly negative end. (49)

Front 588

________ _____ form when the positive end of one polar molecule is attracted to the negative end of another. (49)

Back 588

[HYDROGEN BONDS] form when the positive end of one polar molecule is attracted to the negative end of another. (49)

Front 589

2.3.4 Weak ________ ___________ called van der Waals forces can hold _____ together ___________ when they come close to each other. (49)

Back 589

Weak [CHEMICAL ATTRACTIONS] called van der Waals forces can hold [ATOMS] together [TEMPORARILY] when they come close to each other. (49)

Front 590

2.4.1A Water molecules are polar molecules that form ________ _____ with each other and with other polar molecules. Many of the physical properties of water are attributed to ________ _______. (49)

Back 590

Water molecules are polar molecules that form [HYDROGEN BONDS] with each other and with other polar molecules. Many of the physical properties of water are attributed to [HYDROGEN BONDING]. (49)

Front 591

2.4.1B Because water molecules are attracted to each other by ________ _______, a significant amount of heat energy is needed to pull the _________ apart. For this reason, water heats up ______ and holds it temperature ______. (49)

Back 591

Because water molecules are attracted to each other by [HYDROGEN BONDING], a significant amount of heat energy is needed to pull the [MOLECULES] apart. For this reason, water heats up [SLOWLY] and holds it temperature [LONGER]. (49)

Front 592

2.4.1C The ________ _____ that hold water molecules together become more ______ at lower temperatures, and as a result, they lock water molecules into place in solid crystal structures called ice, such as that shown here from figure 2.9. (49)

Back 592

The [HYDROGEN BONDS] that hold water molecules together become more [STABLE] at lower temperatures, and as a result, they lock water molecules into place in solid crystal structures called ice, such as that shown here from figure 2.9. (49)

Front 593

2.4.1D In order for water to vaporize into a gas, a significant input of ____ ______ is needed to break the hydrogen bonds. This high heat of vaporization is a property of water used by our bodies in ________________. (49)

Back 593

In order for water to vaporize into a gas, a significant input of [HEAT ENERGY] is needed to break the hydrogen bonds. This high heat of vaporization is a property of water used by our bodies in [THERMOREGULATION]. (49)

Front 594

2.4.1E Because water molecules are polar molecules, they will form ________ _____ with other polar molecules. If the other polar molecules are water molecules, the process is called ________. If the other polar molecules are some other substance, the process is called ________. (49)

Back 594

Because water molecules are polar molecules, they will form [HYDROGEN BONDS] with other polar molecules. If the other polar molecules are water molecules, the process is called [COHESION]. If the other polar molecules are some other substance, the process is called [ADHESION]. (49)

Front 595

2.4.1F When _____ molecules form hydrogen bonds with other polar molecules, they will tend to surround other polar molecules, forming a barrier around them called a _________ _____. (49)

Back 595

When [WATER] molecules form hydrogen bonds with other polar molecules, they will tend to surround other polar molecules, forming a barrier around them called a [HYDRATION SHELL]. (49)

Front 596

Polar molecules are said to be ___________ and are _____-_______. (49)

Back 596

Polar molecules are said to be [HYDROPHILIC] and are [WATER-SOLUBLE]. (49)

Front 597

________ molecules do not form hydrogen bonds and will _______ together when placed in water. They are said to be hydrophobic and are _____-_________. (49)

Back 597

[NONPOLAR] molecules do not form hydrogen bonds and will [CLUSTER] together when placed in water. They are said to be hydrophobic and are [WATER-INSOLUBLE]. (49)

Front 598

2.5.1 Water molecules __________, forming negatively charged hydroxide ions (OH-) and positively charged hydrogen ions (H+). This property of water is significant because the _____________ of hydrogen ions in a solution determines its pH. (49)

Back 598

Water molecules [DISSOCIATE], forming negatively charged hydroxide ions (OH-) and positively charged hydrogen ions (H+). This property of water is significant because the [CONCENTRATION] of hydrogen ions in a solution determines its pH. (49)

Front 599

2.5.2 A solution with a higher hydrogen ion concentration is an ____ with specific chemical properties, and a solution with a lower hydrogen ion concentration is a ____ with different chemical properties. (49)

Back 599

A solution with a higher hydrogen ion concentration is an [ACID] with specific chemical properties, and a solution with a lower hydrogen ion concentration is a [BASE] with different chemical properties. (49)

Front 600

2.5.3A Substances called _______ control changes in pH by taking up or releasing H+ into the solution and control pH within a range called the _________ _____. (49)

Back 600

Substances called [BUFFERS] control changes in pH by taking up or releasing H+ into the solution and control pH within a range called the [BUFFERING RANGE]. (49)

Front 601

2.5.3B A buffer that helps ________ blood pH in humans is an acid-base pair consisting of carbonic acid and bicarbonate. This buffering process involves a series of two reversible reactions, one that generates hydrogen ions, ________ pH, and the reverse reaction that takes up hydrogen ions from solution, __________ pH. (49)

Back 601

A buffer that helps [REGULATE] blood pH in humans is an acid-base pair consisting of carbonic acid and bicarbonate. This buffering process involves a series of two reversible reactions, one that generates hydrogen ions, [REDUCING] pH, and the reverse reaction that takes up hydrogen ions from solution, [INCREASING] pH. (49)

Front 602

2.1.1A The smallest particle into which a substance can be divided and still retain all of its chemical properties is: (50)

a. Matter.
b. An atom.
c. A molecule.
d. Mass.

Back 602

2.1.1A The smallest particle into which a substance can be divided and still retain all of its chemical properties is: (50)

a. An atom.

Front 603

2.1.1B The property that distinguishes an atom of one element (carbon, for example) from an atom of another element (oxygen, for example) is: (50)

a. The number of electrons.
b. The number of protons.
c. The number of neutrons.
d. The combined number of protons and neutrons.

Back 603

2.1.1B The property that distinguishes an atom of one element (carbon, for example) from an atom of another element (oxygen, for example) is: (50)

a. The number of protons.

Front 604

2.1.2A Which has more potential energy, an electron closer to an atom’s nucleus or an electron that is farther from the nucleus? (50)

Back 604

Which has more potential energy, an electron closer to an atom’s nucleus or an electron that is farther from the nucleus? (50)

An electron farther from the atom’s nucleus has more potential energy.

Front 605

2.1.2B The difference between an electron shell and an electron orbital is that: (50)

a. An orbital has more mass than an electron shell.
b. Orbitals hold more electrons than shells do.
c. An orbital more precisely locates the volume where an electron is likely to be found.
d. There is no difference.

Back 605

2.1.2B The difference between an electron shell and an electron orbital is that: (50)

a. An orbital more precisely locates the volume where an electron is likely to be found.

Front 606

2.2.1A An atom that has gained or lost one or more electrons is: (50)

a. An isotope.
b. An neutron.
c. An ion.
d. Radioactive.

Back 606

2.2.1A An atom that has gained or lost one or more electrons is: (50)

c. An ion.

Front 607

2.2.1B An atom with a net positive charge must have more: (50)

a. Protons than neutrons.
b. Protons than electrons.
c. Electrons than neutrons.
d. Electrons than protons.

Back 607

2.2.1B An atom with a net positive charge must have more: (50)

b. Protons than electrons.

Front 608

2.2.2A The isotopes carbon-12 and carbon-14 differ in: (50)

a. The number of neutrons.
b. The number of protons.
c. The number of electrons.
d. Both b and c.

Back 608

2.2.2A The isotopes carbon-12 and carbon-14 differ in: (50)

a. The number of neutrons.

Front 609

2.2.2B An ion differs from an isotope in that an ion: (50)

a. Is charged.
b. Has a different number of protons.
c. Has a different number of neutrons.
d. Has a different atomic number.

Back 609

2.2.2B An ion differs from an isotope in that an ion: (50)

a. Is charged.

Front 610

2.2.3A Imagine you were to find a fossilized animal bone containing one-eight the amount of carbon-14 present in earth’s atmosphere today. How long ago did the animal die? (50)

Back 610

Imagine you were to find a fossilized animal bone containing one-eight the amount of carbon-14 present in earth’s atmosphere today. How long ago did the animal die? (50)

The half-life of carbon-14 is 5,730 years. It took 5,730 years for half of the carbon-14 to decay (1/2 left). Then another 5,730 years for that half to half itself (now ¼ left) and another 5,730 years to half the ¼ (=1/8), therefore the fossil is at least 15,190 years old.

Front 611

2.2.3B Explain why it is difficult to use carbon-14 dating on 100-million-year-old dinosaur fossils. (50)

Back 611

Explain why it is difficult to use carbon-14 dating on 100-million-year-old dinosaur fossils. (50)

To use carbon-14 to date a fossil, you must be able to estimate the ratio of 14C to 12C in the fossil. After 5,730 years, the fossil has about half the amount of 14C it had when it died. After 11,460 years, there is only one-fourth the amount of 14C remaining. After the organism has been dead for 50,000 years, there is approximately 1/512 the amount of 14C it started with. This is such a small amount that the measurement becomes very inaccurate.

Front 612

2.3.1A Atoms are held together by a force called a bond. The three principal types of chemical bonds are: (50)

a. Positive, negative, and neutral.
b. Hydrophobic, hydrophilic, and van der Waals interactions.
c. Magnetic, electric, and radioactive.
d. Ionic, covalent, and hydrogen.

Back 612

2.3.1A Atoms are held together by a force called a bond. The three principal types of chemical bonds are: (50)

d. Ionic, covalent, and hydrogen.

Front 613

2.3.1B Ionic bonds: (50)

a. Are highly directional.
b. Are stronger than covalent bonds.
c. Are stronger than hydrogen bonds.
d. Play an important role in most biological molecules.

Back 613

2.3.1B Ionic bonds: (50)

c. Are stronger than hydrogen bonds.

Front 614

2.3.2A Carbon has four electrons in its outer electron shell, and thus: (50)

a. Has a completely filled outer electron shell.
b. Can form four single covalent bonds.
c. Does not react with any other atom.
d. Has a positive charge.

Back 614

2.3.2A Carbon has four electrons in its outer electron shell, and thus: (50)

b. Can form four single covalent bonds.

Front 615

2.3.2B Hydrogen atoms (one valence electron) form a diatomic gas, H2, Oxygen atoms (two valence electrons) form a diatomic gas, O2. Nitrogen atoms (three valence electrons) form a diatomic gas, N2. Carbon atoms (four valence electrons) do NOT form a diatomic gas, C2. Why not? (50)

Back 615

Hydrogen atoms (one valence electron) form a diatomic gas, H2, Oxygen atoms (two valence electrons) form a diatomic gas, O2. Nitrogen atoms (three valence electrons) form a diatomic gas, N2. Carbon atoms (four valence electrons) do NOT form a diatomic gas, C2. Why not? (50)

The electron arrangement of carbon allows it to readily enter into covalent bonds with other elements but its orbital structure does not overlap properly with itself for a diatomic gas to form. With four valence electrons, a quadruple covalent bond would have to form to fill the outer energy shell, and this bond is too unstable and unlikely.

Front 616

2.3.2C Explain why it is possible for a bacterium to break the triple covalent bond of N2 gas, whereas you and other animals cannot. (50)

Back 616

Explain why it is possible for a bacterium to break the triple covalent bond of N2 gas, whereas you and other animals cannot. (50)

Bacteria have certain enzymes not present in humans that allow them to break the covalent bonds between nitrogen atoms.

Front 617

2.3.3A The partial separation of charge in the water molecule: (50)

a. Results from the electrons’ greater attraction to the oxygen atom.
b. Means the molecule has a positive end and a negative end.
c. Indicates that the water molecule is a polar molecule.
d. All of the above.

Back 617

2.3.3A The partial separation of charge in the water molecule: (50)

d. All of the above.

Front 618

2.3.3B Hydrogen bonds: (50)

a. Are highly directional.
b. Are stronger than covalent bonds.
c. Are stronger than ionic bonds.
d. Involve the sharing of electrons.

Back 618

2.3.3B Hydrogen bonds: (50)

a. Are highly directional.

Front 619

2.3.4 Van der Waals attractions: (50)

a. Involve electrical attraction.
b. Are stronger than hydrogen bonds.
c. Are not directional.
d. Involve the sharing of electrons.

Back 619

2.3.4 Van der Waals attractions: (50)

c. Are not directional.

Front 620

2.4.1A Water has some very unusual properties. These properties occur because of the: (50)

a. Hydrogen bonds between the individual water molecules.
b. Covalent bonds between the individual water molecules.
c. Hydrogen bonds within each individual water molecule.
d. Ionic bonds between the individual water molecules.

Back 620

2.4.1A Water has some very unusual properties. These properties occur because of the: (50)

a. Hydrogen bonds between the individual water molecules.

Front 621

2.4.1B Which of the following properties of water is explained by the need for significant heat energy to break many hydrogen bonds? (50)

a. Cohesion and adhesion
b. Hydrophobic and hydrophilic
c. Heat storage and heat of vaporization
d. Ice formation and high polarity

Back 621

2.4.1B Which of the following properties of water is explained by the need for significant heat energy to break many hydrogen bonds? (50)

c. Heat storage and heat of vaporization

Front 622

2.4.1C The attraction of water molecules to other water molecules is called: (50)

a. Cohesion.
b. Capillary action.
c. Solubility.
d. Adhesion.

Back 622

2.4.1C The attraction of water molecules to other water molecules is called: (50)

a. Cohesion.

Front 623

2.4.1D If you add ice cubes to a glass half-full of water, what happens to the level of water in the glass? Does it rise or fall? Explain why. (50)

Back 623

If you add ice cubes to a glass half-full of water, what happens to the level of water in the glass? Does it rise or fall? Explain why. (50)

The level rises because ice is less dense than liquid water, which means that ice will take up more space in the glass of water and thus make the level of liquid water higher.

Front 624

2.5.1 Water sometimes ionizes, a single molecule breaking apart into a hydrogen ion and a hydroxide ion. Other materials may dissociate in water, resulting in either (1) an increase of hydrogen ions or (2) a decrease of hydrogen ions in the solution. We call the results: (50)

a. (1) acids and (2) bases.
b. (1) bases and (2) acids.
c. (1) neutral solutions and (2) neutronic solutions.
d. (1) hydrogen solutions and (2) hydroxide solutions.

Back 624

2.5.1 Water sometimes ionizes, a single molecule breaking apart into a hydrogen ion and a hydroxide ion. Other materials may dissociate in water, resulting in either (1) an increase of hydrogen ions or (2) a decrease of hydrogen ions in the solution. We call the results: (50)

a. (1) acids and (2) bases.

Front 625

2.5.2 A solution with a high concentration of hydrogen ions: (50)

a. Is called a base.
b. Is called an acid.
c. Has a high pH.
d. Both b and c.

Back 625

2.5.2 A solution with a high concentration of hydrogen ions: (50)

b. Is called an acid.

Front 626

2.5.3 Which of the following is not true about buffers? (50)

a. A buffer takes up H+ from the solution.
b. A buffer keeps the pH relatively constant.
c. A buffer stops water from ionizing.
d. A buffer releases H+ into the solution.

Back 626

2.5.3 Which of the following is not true about buffers? (50)

c. A buffer stops water from ionizing.

Front 627

Formed by living organisms and consist of a carbon-based core with special groups attached. A molecule of the kind normally found in living systems; are usually composed of carbon atoms in rings or long chains, to which are attached other atoms of such elements as hydrogen, oxygen, and nitrogen.

Back 627

1. Organic Molecules (52)

Front 628

An extremely large molecule. Refers specifically to carbohydrates, lipids, proteins, and nucleic acids.

Back 628

1. Macromolecules (52)

Front 629

Simple molecules that can join together to form polymers.

Back 629

1. Monomers (52)

Front 630

A large molecule formed of long chains of similar molecules called monomers.

Back 630

1. Polymer (52)

Front 631

A chemical reaction that builds up molecules by losing water molecules. It is a type of condensation reaction in which monomers join together into polymers while losing water molecules. This process is carried out by losing (-OH) from one of the monomers and (H) from another monomer. The two unstable monomers join together, and the (-OH) and (H) combine forming water (H2O).

Back 631

1. Dehydration Synthesis (53)

Front 632

A protein capable of speeding up specific chemical reactions by lowering the energy required to activate or start the reaction but that remains unaltered in the process.

Back 632

1. Enzymes (53)

Front 633

The chemical breakdown of a compound due to reaction with water.

Back 633

1. Hydrolysis (53)

Front 634

A long chain of amino acids linked end to end by peptide bonds. Because the 20 amino acids that occur in proteins have side groups with very different chemical properties, the function and shape of a protein are critically affected by its particular sequence of amino acids.

Back 634

1. Proteins (54)

Front 635

The subunit structure from which proteins are produced, consisting of a central carbon atom with a carboxyl group (COOH), an amino group (-NH2), a hydrogen, and a side group (R group); only the side group differs from one amino acid to another.

Back 635

1. Amino Acids (54)

Front 636

A covalent bond linking two amino acids. Formed when the positive (amino, or NH2) group at one end and a negative (carboxyl, or COOH) group at the other end undergo a chemical reaction and lose a molecule of water.

Back 636

1. Peptide Bond (54)

Front 637

A general term for a long chain of amino acids linked end to end by peptide bonds. A protein is a long, complex ___________.

Back 637

1. Polypeptides (54)

Front 638

The characteristic sequence of amino acids forming a protein or polypeptide chain, considered as the most basic element of its structure.

Back 638

1. Primary Structure (56)

Front 639

The local three-dimensional structure of sheets, helices, or other forms adopted by a polynucleotide or polypeptide chain, due to electrostatic attraction between neighboring residues.

Back 639

1. Secondary Structure (56)

Front 640

The overall three-dimensional structure resulting from folding and covalent cross-linking of a protein or polynucleotide molecule.

Back 640

1. Tertiary Structure (56)

Front 641

The structure that is formed by the joining together of two or more proteins or nucleic acids. The functions of the proteins and nucleic acids are only expressed correctly when they are joined together.

Back 641

1. Quaternary Structure (56)

Front 642

To destroy the characteristic properties of (a protein or other biological macromolecule) by heat, acidity, or other effects that disrupt its molecular conformation.

Back 642

1. Denatured (57)

Front 643

The enzyme-mediated process in which the subunits of polymers are positioned so that their bonds undergo chemical reactions.

Back 643

1. Catalysis (57)

Front 644

Molecular __________ are ________ that assist the non-covalent folding or unfolding and the assembly or disassembly of other macromolecular structures.

Back 644

1. Chaperone Proteins (58)

Front 645

A small proteinaceous infectious disease-causing agent that is believed to be the smallest infectious particle. A _____ is neither bacterial nor fungal nor viral and contains no genetic material. ______ have been held responsible for a number of degenerative brain diseases, including mad cow disease, Creutzfeldt-Jakob disease, fatal familial insomnia, kuru, and an unusual form of hereditary dementia known as Gertsmann-Straeussler-Scheinker disease.

Back 645

1. Prions (58)

Front 646

Also known as prion diseases, are a group of progressive conditions (encephalopathies) that affect the brain and nervous system of many animals, including humans. These diseases include scrapie in sheep, “mad cow” disease in cattle, and kuru and Creutzfeldt-Jakob disease in humans.

Back 646

1. Transmissible Spongiform Encephalopathies (TSEs) (59)

Front 647

A degenerative neurologic disease of cattle, thought to be caused by infection-causing agents called prions, in which brain tissues deteriorate and take on a spongy appearance, resulting in abnormal behaviors and loss of muscle control. A variant form of Creutzfeldt-Jakob disease is transmitted to humans through the eating of infected cattle tissue. Also called bovine spongiform encephalopathy.

Back 647

1. Mad Cow Disease (59)

Front 648

A nucleotide polymer. A long chain of nucleotides. Chief types are deoxyribonucleic acid (DNA), which is double-stranded, and ribonucleic acid (RNA), which is typically single-stranded.

Back 648

1. Nucleic Acids (60)

Front 649

A single unit of a nucleic acid, composed of a phosphate, a five-carbon sugar (either ribose or deoxyribose), and a purine or a pyrimidine.

Back 649

1. Nucleotides (60)

Front 650

A sequence of nucleotides, as in DNA or RNA, bound into a chain. ______________. A linear polymer containing an indefinite, usually large, number of nucleotides linked from one ribose or deoxyribose to another by phosphoric residues.

Back 650

1. Polynucleotide Chains (60)

Front 651

The basic storage vehicle or central plan of heredity information. It is stored as a sequence of nucleotides in a linear nucleotide polymer. Two of the polymers wind around each other like the outside and inside rails of a circular staircase.

Back 651

1. Deoxyribonucleic Acid (DNA) (60)

Front 652

A class of nucleic acids characterized by the presence of the sugar ribose and the pyrimidine uracil; includes mRNA, tRNA, rRNA, and siRNA.

Back 652

1. Ribonucleic Acid (RNA) (60)

Front 653

A pair of parallel helices intertwined about a common axis, especially that in the structure of the DNA molecule.

Back 653

1. Double Helix (61)

Front 654

An organic compound consisting of a chain or ring of carbon atoms to which hydrogen and oxygen atoms are attached in a ratio of approximately 1:2:1. A compound of carbon, hydrogen, and oxygen having the generalized formula (CH2O)n, where n is the number of carbon atoms.

Back 654

1. Carbohydrates (63)

Front 655

A simple sugar.

Back 655

1. Monosaccharides (63)

Front 656

A sugar formed by linking two monosaccharide molecules together. Sucrose (table sugar) is a disaccharide formed by linking a molecule of glucose to a molecule of fructose.

Back 656

1. Disaccharide (63)

Front 657

A sugar polymer. A carbohydrate composed of many monosaccharide sugar subunits linked together in a long chain.

Back 657

1. Polysaccharides (63)

Front 658

The glucose polysaccharide that plants use to store energy. An odorless tasteless white substance occurring widely in plant tissue and obtained chiefly from cereals and potatoes. It is a polysaccharide that functions as a carbohydrate store and is an important constituent of the human diet.

Back 658

1. Starch (63)

Front 659

In animals, energy is stored in this, an insoluble macromolecule formed of long glucose polysaccharides that are highly branched. A substance deposited in bodily tissues as a store of carbohydrates. It is a polysaccharide that forms glucose on hydrolysis.

Back 659

1. Glycogen (63)

Front 660

Animals also use glucose chains as building materials, linking the subunits together in different orientations not recognized by most enzymes. A fibrous substance consisting of polysaccharides and forming the major constituent in the exoskeleton of arthropods and the cell walls of fungi.

Back 660

1. Chitin (63)

Front 661

Plants also use glucose chains as building materials, linking the subunits together in different orientations not recognized by most enzymes. An insoluble substance that is the main constituent of plant cell walls and of vegetable fibers such as cotton. It is a polysaccharide consisting of chains of glucose monomers.

Back 661

1. Cellulose (63)

Front 662

A loosely defined group of molecules that are insoluble in water but soluble in oil. Oils such as olive, corn, and coconut are lipids, as well as waxes, such as beeswax and earwax.

Back 662

1. Lipids (65)

Front 663

A long chain of carbon and hydrogen atoms (called a hydrocarbon) ending in a carboxyl (-COOH) group. A carboxylic acid consisting of a hydrocarbon chain and a terminal carboxyl group, especially any of those occurring as esters in fats and oils.

Back 663

1. Fatty Acid (65)

Front 664

An ester formed from glycerol and three fatty acid groups. _____________ are the main constituents of natural fats and oils, and high concentrations in the blood indicate an elevated risk of stroke.

Back 664

1. Triglyceride (65)

Front 665

Containing the greatest possible number of hydrogen atoms, and so having no carbon–carbon double or triple bonds.

Back 665

1. Saturated (65)

Front 666

Fats composed of fatty acids that have double bonds between one or more pairs of carbon atoms contain fewer than the maximum number of hydrogen atoms. Having carbon–carbon double or triple bonds and therefore not containing the greatest possible number of hydrogen atoms for the number of carbons. Denoting fats containing a high proportion of fatty acid molecules with at least one double bond, considered to be healthier in the diet than saturated fats.

Back 666

1. Unsaturated (65)

Front 667

Macromolecules: Organic Molecules – formed by ______ organisms and consist of a carbon-based core with ‘_______ groups’ attached.

Back 667

Macromolecules: Organic Molecules – formed by [LIVING] organisms and consist of a carbon-based core with ‘[SPECIAL GROUPS]’ attached.

Front 668

Macromolecules: Functional Groups – ‘special groups’ with special chemical properties that tend to act as _____ during chemical reactions.

Back 668

Macromolecules: Functional Groups – ‘special groups’ with special chemical properties that tend to act as [UNITS] during chemical reactions.

Front 669

Macromolecules: Macromolecules – very large macromolecules that make up a lot of the body (________, nucleic acids, _____________, lipids).

Back 669

Macromolecules: Macromolecules – very large macromolecules that make up a lot of the body ([PROTEINS], nucleic acids, [CARBOHYDRATES], lipids).

Front 670

Polymers are made of Monomers: Monomer – _______ _____ attached like a train.

Back 670

Polymers are made of Monomers: Monomer – [SMALLER PARTS] attached like a train.

Front 671

Polymers are made of Monomers: Polymer – ________ build of monomers.

Back 671

Polymers are made of Monomers: Polymer – [MOLECULE] build of monomers.

Front 672

Polymers are made of Monomers: Bonds can be formed or broken using special proteins (_______) to facilitate the ___________ of molecules.

Back 672

Polymers are made of Monomers: Bonds can be formed or broken using special proteins ([ENZYMES]) to facilitate the [POSITIONING] of molecules.

Front 673

Polymers are made of Monomers: Dehydration Synthesis – ________ ____ formed by the removal of OH and H groups (molecule of water).

Back 673

Polymers are made of Monomers: Dehydration Synthesis – [COVALENT BOND] formed by the removal of OH and H groups (molecule of water).

Front 674

__________ – breaking of a polymer by adding H to one subunit and OH to another thus breaking the covalent bond.

Back 674

[HYDROLYSIS] – breaking of a polymer by adding H to one subunit and OH to another thus breaking the covalent bond.

Front 675

Proteins: Proteins – complex biological macromolecules (________) with a big role in the body.

Back 675

Proteins: Proteins – complex biological macromolecules ([POLYMERS]) with a big role in the body.

Front 676

Proteins: Enzymes – _____ the energy required to initiation a particular ________ reaction.

Back 676

Proteins: Enzymes – [LOWER] the energy required to initiation a particular [CHEMICAL] reaction.

Front 677

Proteins: Structural Roles – Collagen makes up _________, _____ and _______ made of collagen.

Back 677

Proteins: Structural Roles – Collagen makes up [CARTILAGE], [BONES] and [TENDONS] made of collagen.

Front 678

Proteins: Structural Roles – _______ forms hair, horns or rhinoceros and feathers.

Back 678

Proteins: Structural Roles – [KERATIN] forms hair, horns or rhinoceros and feathers.

Front 679

Proteins: Structural Roles – Chemical messengers. (?)

Back 679

Proteins: Structural Roles – Chemical messengers. (?)

Front 680

Proteins: Amino Acids are monomers with a ______ base structure (amino and carboxyl groups) and a __________ group (R).

Back 680

Proteins: Amino Acids are monomers with a [SIMPLE] base structure (amino and carboxyl groups) and a [FUNCTIONAL] group (R).

Front 681

Proteins: Peptide Bond – covalent bond that links two _____ _____ via dehydration synthesis.

Back 681

Proteins: Peptide Bond – covalent bond that links two [AMINO ACIDS] via dehydration synthesis.

Front 682

Proteins: Polypeptide – long chains of amino acids linked by _______ _____.

Back 682

Proteins: Polypeptide – long chains of amino acids linked by [PEPTIDE BONDS].

Front 683

Proteins: Protein structures are viewed in 4 parts – Primary Structure – sequence of _____ _____.

Back 683

Proteins: Protein structures are viewed in 4 parts – Primary Structure – sequence of [AMINO ACIDS].

Front 684

Proteins: Protein structures are viewed in 4 parts – Secondary Structure – repeated ________ formed by hydrogen bonds between R groups (α-_____).

Back 684

Proteins: Protein structures are viewed in 4 parts – Secondary Structure – repeated [PATTERNS] formed by hydrogen bonds between R groups (α-[HELIX]).

Front 685

Proteins: Protein structures are viewed in 4 parts – Secondary Structure – repeated patterns formed by ________ _____ between R groups (β-_______ _____).

Back 685

Proteins: Protein structures are viewed in 4 parts – Secondary Structure – repeated patterns formed by [HYDROGEN BONDS] between R groups (β-[PLEATED SHEET]).

Front 686

Proteins: Protein structures are viewed in 4 parts – Tertiary Structure – entire _______ and ________ of a polypeptide.

Back 686

Proteins: Protein structures are viewed in 4 parts – Tertiary Structure – entire [FOLDING] and [TWISTING] of a polypeptide.

Front 687

Proteins: Protein structures are viewed in 4 parts – Quaternary structure – contains >1 ___________.

Back 687

Proteins: Protein structures are viewed in 4 parts – Quaternary structure – contains >1 [POLYPEPTIDE].

Front 688

Proteins: Protein _______ is a result of the polar, watery, environment of the cell and the _____ formed between R groups.

Back 688

Proteins: Protein [FOLDING] is a result of the polar, watery, environment of the cell and the [BONDS] formed between R groups.

Front 689

Proteins: Some proteins do not fold properly and need the aid of ________ ________ to help it fold correctly.

Back 689

Proteins: Some proteins do not fold properly and need the aid of [CHAPERONE PROTEINS] to help it fold correctly.

Front 690

Proteins: Proteins that do not fold properly can lead to _______.

Back 690

Proteins: Proteins that do not fold properly can lead to [DISEASE].

Front 691

Proteins: Proteins that do not fold properly can lead to disease – __________ _______ – could be in part due to chaperone protein ____________ leading to amyloid protein clumping in brain cells.

Back 691

Proteins: Proteins that do not fold properly can lead to disease – [ALZHEIMER’S DISEASE] – could be in part due to chaperone protein [DEFICIENCIES] leading to amyloid protein clumping in brain cells.

Front 692

Proteins: Proteins that do not fold properly can lead to disease – ___ ___ _______ and ___________-_____ _______ – caused by misfolded brain proteins (prions) that induce other brain prion proteins to misfold, thus forming a _____ ________ of misfolding killing more brain cells.

Back 692

Proteins: Proteins that do not fold properly can lead to disease – [MAD COW DISEASE] and [CREUTZFELDT-JACOB DISEASE] – caused by misfolded brain proteins (prions) that induce other brain prion proteins to misfold, thus forming a [CHAIN REACTION] of misfolding killing more brain cells.

Front 693

Proteins: Denaturing (_________ of a protein) occurs when the cellular environment _______ altering hydrogen bonds.

Back 693

Proteins: Denaturing ([UNFOLDING] of a protein) occurs when the cellular environment [CHANGES] altering hydrogen bonds.

Front 694

Proteins: 1OF 5 BIOLOGICAL THEMES – Protein _________ determines ________. Enzymes fold into globular structures to make an active site where a ________ takes place acting as a catalyst.

Back 694

Proteins: 1OF 5 BIOLOGICAL THEMES – Protein [STRUCTURE] determines [FUNCTION]. Enzymes fold into globular structures to make an active site where a [REACTION] takes place acting as a catalyst.

Front 695

Proteins: 1OF 5 BIOLOGICAL THEMES – Protein structure determines function. Many structural proteins form long ______ like the contractile proteins of muscle cells.

Back 695

Proteins: 1OF 5 BIOLOGICAL THEMES – Protein structure determines function. Many structural proteins form long [CABLES] like the contractile proteins of muscle cells.

Front 696

Nucleic Acids: _______ _____ are polymers that act as the information storage device of cells. This polymer is made of monomers called ___________ that are organized into 5 parts.

Back 696

Nucleic Acids: [NUCLEIC ACIDS] are polymers that act as the information storage device of cells. This polymer is made of monomers called [NUCLEOTIDES] that are organized into 5 parts.

Front 697

Nucleic Acids: A ______________ chain is formed when the 5-carbon sugars are linked with a _________ group.

Back 697

Nucleic Acids: A [POLYNUCLEOTIDE] chain is formed when the 5-carbon sugars are linked with a [PHOSPHATE] group.

Front 698

Nucleic Acids: ________________ ____ (DNA) vs. ___________ ____ (RNA)

Back 698

Nucleic Acids: [DEOXYRIBONUCLEIC ACID] (DNA) vs. [RIBONUCLEIC ACID] (RNA)

Front 699

Nucleic Acids: DNA is a ______ _____.

Back 699

Nucleic Acids: DNA is a [DOUBLE HELIX].

Front 700

Nucleic Acids: 1 OF 5 CHARACTERISTICS FOR BEING ALIVE – DNA is the __________ information that is passed on to offspring.

Back 700

Nucleic Acids: 1 OF 5 CHARACTERISTICS FOR BEING ALIVE – DNA is the [HEREDITARY] information that is passed on to offspring.

Front 701

Carbohydrates: Carbohydrates are ________ that make up the structural framework of cells and play a critical role in storing ______.

Back 701

Carbohydrates: Carbohydrates are [POLYMERS] that make up the structural framework of cells and play a critical role in storing [ENERGY].

Front 702

Carbohydrates: Simple Carbohydrate – small ________ or dimmers.

Back 702

Carbohydrates: Simple Carbohydrate – small [MONOMERS] or dimmers.

Front 703

Carbohydrates: Complex Carbohydrate – long ________.

Back 703

Carbohydrates: Complex Carbohydrate – long [POLYMERS].

Front 704

Carbohydrates: Simple Carbohydrate – ______________ or “simple sugar.”

Back 704

Carbohydrates: Simple Carbohydrate – [MONOSACCHARIDE] or “simple sugar.”

Front 705

Carbohydrates: Simple Carbohydrate – ____________, dimer.

Back 705

Carbohydrates: Simple Carbohydrate – [DISACCHARIDE], dimer.

Front 706

Carbohydrates: Complex Carbohydrates – polysaccharides (______ and ________).

Back 706

Carbohydrates: Complex Carbohydrates – polysaccharides ([STARCH] and [GLYCOGEN]).

Front 707

Carbohydrates: Complex Carbohydrates – polysaccharides – Starch – glucose polysaccharide that ______ use to store energy.

Back 707

Carbohydrates: Complex Carbohydrates – polysaccharides – Starch – glucose polysaccharide that [PLANTS] use to store energy.

Front 708

Carbohydrates: Complex Carbohydrates – polysaccharides – Glycogen – highly branched soluble glucose polysaccharide that _______ use to store energy.

Back 708

Carbohydrates: Complex Carbohydrates – polysaccharides – Glycogen – highly branched soluble glucose polysaccharide that [ANIMALS] use to store energy.

Front 709

Carbohydrates: Complex Carbohydrates – polysaccharides – Chitin (______) and Cellulose (_______) – glucose chains used as building materials, linking the subunits together in different ____________ not recognized by most enzymes.

Back 709

Carbohydrates: Complex Carbohydrates – polysaccharides – Chitin ([PLANTS]) and Cellulose ([ANIMALS]) – glucose chains used as building materials, linking the subunits together in different [ORIENTATIONS] not recognized by most enzymes.

Front 710

Lipids: Lipids are nonpolar polymers, thus _________ in water, used for ____-term energy storage and other functions within the cell.

Back 710

Lipids: Lipids are nonpolar polymers, thus [INSOLUBLE] in water, used for [LONG]-term energy storage and other functions within the cell.

Front 711

Lipids: Fats (_____________) are lipids made of fatty acids (long chain of carbon and hydrogen) and a ________ backbone.

Back 711

Lipids: Fats ([TRIGLYCERIDES]) are lipids made of fatty acids (long chain of carbon and hydrogen) and a [GLYCEROL] backbone.

Front 712

Lipids: Saturated fats are fatty acids with all ________ carbon atoms forming ________ bonds with 2 hydrogen atoms contain the maximum number of hydrogen atoms.

Back 712

Lipids: Saturated fats are fatty acids with all [INTERNAL] carbon atoms forming [COVALENT] bonds with 2 hydrogen atoms contain the maximum number of hydrogen atoms.

Front 713

Lipids: Saturated fats are _____ at room temperature.

Back 713

Lipids: Saturated fats are [SOLID] at room temperature.

Front 714

Lipids: Unsaturated fats are fatty acids with some ________ carbons having ______ bonds, thus contain fewer than the maximum number of hydrogen atoms.

Back 714

Lipids: Unsaturated fats are fatty acids with some [INTERNAL] carbons having [DOUBLE] bonds, thus contain fewer than the maximum number of hydrogen atoms.

Front 715

Lipids: Most unsaturated fats are ______ at room temperature due to the _____ formed by the double bonds.

Back 715

Lipids: Most unsaturated fats are [LIQUID] at room temperature due to the [KINKS] formed by the double bonds.

Front 716

Lipids: Some ___________ fatty acids have artificially hydrogenated (addition of more hydrogen), making them more _________, to extend the shelf-life of a product.

Back 716

Lipids: Some [UNSATURATED] fatty acids have artificially hydrogenated (addition of more hydrogen), making them more [SATURATED], to extend the shelf-life of a product.

Front 717

Lipids: Trans fats can sometimes be created by ____________ in which some of the double bonds are less kinked than naturally occurring unsaturated fats.

Back 717

Lipids: Trans fats can sometimes be created by [HYDROGENATED] in which some of the ______ bonds are less kinked than naturally occurring unsaturated fats.

Front 718

Lipids: Eating trans fats and saturated fats can increase the risk of _____ _______.

Back 718

Lipids: Eating trans fats and saturated fats can increase the risk of [HEART DISEASE].

Front 719

Lipids: ________ are lipids that consist of ________ ring structures – Testosterone (male sex hormone).

Back 719

Lipids: [STEROIDS] are lipids that consist of [MULTIPLE] ring structures – Testosterone (male sex hormone).

Front 720

Lipids: Steroids are ______ that consist of multiple ring structures – _________ (female sex hormone).

Back 720

Lipids: Steroids are [LIPIDS] that consist of multiple ring structures – [ESTRADIOL] (female sex hormone).

Front 721

Lipids: Steroids are lipids that consist of multiple ____ __________ – ___________.

Back 721

Lipids: Steroids are lipids that consist of multiple [RING STRUCTURES] – [CHOLESTEROL].

Front 722

Lipids: Phospholipids are modified _______________ molecules where one of the carbons in the glycerol backbone bonds to a phosphate group instead of a third _____ ____.

Back 722

Lipids: Phospholipids are modified [TRIACYLGLYCEROL] molecules where one of the carbons in the glycerol backbone bonds to a phosphate group instead of a third [Fatty Acid].

Front 723

Lipids: The phosphate group gives the phospholipid molecule an overall shape of a _____ head with 2 ________ tails. Group together to form a lipid bilayer.

Back 723

Lipids: The phosphate group gives the phospholipid molecule an overall shape of a [POLAR] head with 2 [NONPOLAR] tails. Group together to form a lipid bilayer.

Front 724

Lipids: Other important biological lipids are ______, _____ and ________ (such as chlorophyll that makes plants green and the retinal that your eyes use to detect light).

Back 724

Lipids: Other important biological lipids are [RUBBER], [WAXES] and [PIGMENTS] (such as chlorophyll that makes plants green and the retinal that your eyes use to detect light).

Front 725

The bodies of organisms contain thousands of different kinds of _________ and _____. Organisms obtain many of these molecules from their ____________ and from what they consume. (52)

Back 725

The bodies of organisms contain thousands of different kinds of [MOLECULES] and [ATOMS]. Organisms obtain many of these molecules from their [SURROUNDINGS] and from what they consume. (52)

Front 726

You might be familiar with some of the substances listed on nutritional labels, such as the one shown in figure 3.1. But what do the words on these labels mean? Some of them are names of ________ (atoms, see chapter 2), such as calcium and iron, and others are ________. (52)

Back 726

You might be familiar with some of the substances listed on nutritional labels, such as the one shown in figure 3.1. But what do the words on these labels mean? Some of them are names of [MINERALS] (atoms, see chapter 2), such as calcium and iron, and others are [VITAMINS]. (52)

Front 727

Still others (what’s on nutrition labels) are the subject of this chapter: large molecules that make up the bodies of organisms and are found in our food, such as proteins, carbohydrates (including sugars), and lipids (including, fats, trans fats, saturated fats, and cholesterol). These molecules, called _______ molecules, are formed by living organisms and consist of a carbon-based core with special groups attached. These groups of atoms have special chemical properties and are referred to as __________ groups. (52)

Back 727

Still others (what’s on nutrition labels) are the subject of this chapter: large molecules that make up the bodies of organisms and are found in our food, such as proteins, carbohydrates (including sugars), and lipids (including, fats, trans fats, saturated fats, and cholesterol). These molecules, called [ORGANIC] molecules, are formed by living organisms and consist of a carbon-based core with special groups attached. These groups of atoms have special chemical properties and are referred to as [FUNCTIONAL] groups. (52)

Front 728

Functional groups tend to act as _____ during chemical reactions and to confer specific chemical properties on the _________ that possess them. Five principal functional groups are listed in figure 3.2; the last column indicates the types of organic molecules that contain these functional groups. (52)

Back 728

Functional groups tend to act as [UNITS] during chemical reactions and to confer specific chemical properties on the [MOLECULES] that possess them. [FIVE] principal functional groups are listed in figure 3.2; the last column indicates the types of organic molecules that contain these functional groups. (52)

Front 729

The bodies of organisms contain thousands of different kinds of organic molecules, but much of the body is made of just four kinds: ________, _______ _____, _____________, and ______. Called ______________ because they can be very large, these four are the building materials of cells, the “bricks and mortar” that make up the bodies of cells and the machinery that runs within them. (52)

Back 729

The bodies of organisms contain thousands of different kinds of organic molecules, but much of the body is made of just four kinds: [PROTEINS], [NUCLEIC ACIDS], [CARBOHYDRATES], and [LIPIDS]. Called [MACROMOLECULES] because they can be very large, these four are the building materials of cells, the “bricks and mortar” that make up the bodies of cells and the machinery that runs within them. (52)

Front 730

The body’s macromolecules are assembled by sticking smaller bits, called ________, together, much as a train is built by linking railcars together. A molecule built up of long chains of similar subunits is called a _______. Table 3.1 lists the monomers in the first column that make up the polymers that are the basis for many ________ structures. (52)

Back 730

The body’s macromolecules are assembled by sticking smaller bits, called [MONOMERS], together, much as a train is built by linking railcars together. A molecule built up of long chains of similar subunits is called a [POLYMER]. Table 3.1 lists the monomers in the first column that make up the polymers that are the basis for many [CELLULAR] structures. (52)

Front 731

Figure 3.2 – Five principal functional groups. These functional groups can be ___________ from one molecule to another and are common in organic molecules. (52)

Back 731

Figure 3.2 – Five principal functional groups. These functional groups can be [TRANSFERRED] from one molecule to another and are common in organic molecules. (52)

Front 732

Figure 3.1 – What’s in a nutritional label? ____, ___________, _____________, ______, and ________ are just some of the molecules found in popcorn and discussed in this chapter. (52)

Back 732

Figure 3.1 – What’s in a nutritional label? [FATS], [CHOLESTEROL], [CARBOHYDRATES], [SUGARS], and [PROTEINS] are just some of the molecules found in popcorn and discussed in this chapter. (52)

Front 733

The four different kinds of macromolecules (________, _______ _____, _____________, and ______) are all put together in the same way: a ________ ____ is formed between two subunits in which a hydroxyl group (OH) is removed from one subunit and a hydrogen (H) is removed from the other. (53)

Back 733

The four different kinds of macromolecules ([PROTEINS], [NUCLEIC ACIDS], [CARBOHYDRATES], and [LIPIDS]) are all put together in the same way: a [COVALENT BOND] is formed between two subunits in which a hydroxyl group (OH) is removed from one subunit and a hydrogen (H) is removed from the other. (53)

Front 734

This process (illustrated in figure 3.3a) is called dehydration synthesis because, in effect, the removal of the OH and H groups (highlighted by the blue oval) constitutes removal of a ________ of water – the word dehydration means “taking away water.” (53)

Back 734

This process (illustrated in figure 3.3a) is called dehydration synthesis because, in effect, the removal of the OH and H groups (highlighted by the blue oval) constitutes removal of a [MOLECULE] of water – the word dehydration means “taking away water.” (53)

Front 735

Dehydration synthesis requires the help of a special class of proteins called _______ to facilitate the positioning of the molecules so that the correct chemical _____ are stressed and broken. (53)

Back 735

Dehydration synthesis requires the help of a special class of proteins called [ENZYMES] to facilitate the positioning of the molecules so that the correct chemical [BONDS] are stressed and broken. (53)

Front 736

The process of tearing down a molecule, such as the protein or fat contained in food that is consumed, is essentially the _______ of dehydration synthesis: Instead of removing a water molecule, one is added. When a water molecule comes in, as shown in figure 3.3b, a hydrogen becomes attached to one subunit and a hydroxyl to another, and the covalent bond is broken. The breaking up of a polymer in this way is called __________. (53)

Back 736

The process of tearing down a molecule, such as the protein or fat contained in food that is consumed, is essentially the [REVERSE] of dehydration synthesis: Instead of removing a water molecule, one is added. When a water molecule comes in, as shown in figure 3.3b, a hydrogen becomes attached to one subunit and a hydroxyl to another, and the covalent bond is broken. The breaking up of a polymer in this way is called [HYDROLYSIS]. (53)

Front 737

Key Learning Outcome 3.1 – Macromolecules are formed by linking subunits together into long chains, ________ a water molecule as each link is formed. In contrast, macromolecules are broken down into their subunits by hydrolysis reactions, the ________ of water molecules. (53)

Back 737

Key Learning Outcome 3.1 – Macromolecules are formed by linking subunits together into long chains, [REMOVING] a water molecule as each link is formed. In contrast, macromolecules are broken down into their subunits by hydrolysis reactions, the [ADDITION] of water molecules. (53)

Front 738

Figure 3.3 – Dehydration and hydrolysis. (a) Biological molecules are formed by linking subunits. The ________ bond between subunits is formed in dehydration synthesis, a process during which a water molecule is __________. (b) Breaking such a bond requires the addition of a water molecule, a reaction called __________. (53)

Back 738

Figure 3.3 – Dehydration and hydrolysis. (a) Biological molecules are formed by linking subunits. The [COVALENT] bond between subunits is formed in dehydration synthesis, a process during which a water molecule is [ELIMINATED]. (b) Breaking such a bond requires the addition of a water molecule, a reaction called [HYDROLYSIS]. (53)

Front 739

Complex macromolecules called proteins are a major group of biological macromolecules within the bodies of _________. Figure 3.4 presents an overview of the wide-ranging functions of proteins.

Back 739

Complex macromolecules called proteins are a major group of biological macromolecules within the bodies of [ORGANISMS]. Figure 3.4 presents an overview of the wide-ranging functions of proteins.

Front 740

Despite their diverse functions, all ________ have the same basic structure: a long polymer chain made of subunits called _____ _____. (54)

Back 740

Despite their diverse functions, all [PROTEINS] have the same basic structure: a long polymer chain made of subunits called [AMINO ACIDS]. (54)

Front 741

Amino acids are _____ molecules with a simple basic structure: a central carbon atom to which an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a functional group, designated “R,” are ______. (54)

Back 741

Amino acids are [SMALL] molecules with a simple basic structure: a central carbon atom to which an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a functional group, designated “R,” are [BONDED]. (54)

Front 742

There are 20 common kinds of amino acids that differ from one another by the ________ of their functional R group. (54)

Back 742

There are 20 common kinds of amino acids that differ from one another by the [IDENTITY] of their functional R group. (54)

Front 743

The 20 amino acids are classified into ____ general groups, with representative amino acids shown in figure 3.5 (their R groups are highlighted in white). (54)

Back 743

The 20 amino acids are classified into [FOUR] general groups, with representative amino acids shown in figure 3.5 (their R groups are highlighted in white). (54)

Front 744

Six of the amino acids are ________, differing chiefly in size – the most bulky contain ring structures (like asparagine in the upper right), and these differ from one another in the strength of their ________. (54)

Back 744

Six of the amino acids are [NONPOLAR], differing chiefly in size – the most bulky contain ring structures (like asparagine in the upper right), and these differ from one another in the strength of their [POLARITY]. (54)

Front 745

Five more (amino acids) are polar and are capable of ________ to a charged form (like aspartic acid in the lower left). (54)

Back 745

Five more (amino acids) are polar and are capable of [IONIZING] to a charged form (like aspartic acid in the lower left). (54)

Front 746

The remaining three possess special ________ groups (like the white highlighted area of proline in the lower right) that are important in forming links between chains or in forming kinks in their ______. (54)

Back 746

The remaining three possess special [CHEMICAL] groups (like the white highlighted area of proline in the lower right) that are important in forming links between chains or in forming kinks in their [SHAPES]. (54)

Front 747

The ________ of the R groups is important to the proper folding of the protein into its functional shape. (54)

Back 747

The [POLARITY] of the R groups is important to the proper folding of the protein into its functional shape. (54)

Front 748

An individual protein is made by linking specific _____ _____ together in a particular order, just as a word is made by linking specific letters of the alphabet together in a particular order. (54)

Back 748

An individual protein is made by linking specific [AMINO ACIDS] together in a particular order, just as a word is made by linking specific letters of the alphabet together in a particular order. (54)

Front 749

The covalent bond linking two amino acids together is called a _______ bond and forms by ___________ _________. (54)

Back 749

The covalent bond linking two amino acids together is called a [PEPTIDE] bond and forms by [DEHYDRATION SYNTHESIS]. (54)

Front 750

Recall from section 3.1 that in dehydration synthesis, water is formed as a by-product of the ________. You can see in figure 3.6 that a water molecule is released as the peptide bond forms. (54)

Back 750

Recall from section 3.1 that in dehydration synthesis, water is formed as a by-product of the [REACTION]. You can see in figure 3.6 that a water molecule is released as the peptide bond forms. (54)

Front 751

Long chains of amino acids linked by peptide bonds are called ____________. (54)

Back 751

Long chains of amino acids linked by peptide bonds are called [POLYPEPTIDES]. (54)

Front 752

Functional polypeptides are more commonly called ________. (54)

Back 752

Functional polypeptides are more commonly called [PROTEINS]. (54)

Front 753

Figure 3.5 – Examples of amino acids. There are four general groups of amino acids that differ in their __________ ______ (highlighted in white). (54)

Back 753

Figure 3.5 – Examples of amino acids. There are four general groups of amino acids that differ in their [FUNCTIONAL GROUPS] (highlighted in white). (54)

Front 754

Figure 3.6 – The formation of a peptide bond. Every amino acid has the same basic _________, with an amino group (-NH2) at one end and a carboxyl group (-COOH) at the other. The only variable is the functional, or “_,” _____. (54)

Back 754

Figure 3.6 – The formation of a peptide bond. Every amino acid has the same basic [STRUCTURE], with an amino group (-NH2) at one end and a carboxyl group (-COOH) at the other. The only variable is the functional, or “[R,” GROUP]. (54)

Front 755

Amino acids are linked by ___________ _________ to form peptide bonds. Chains of amino acids linked in this way are called polypeptides and are the basic structural components of ________. (54)

Back 755

Amino acids are linked by [DEHYDRATION SYNTHESIS] to form peptide bonds. Chains of amino acids linked in this way are called polypeptides and are the basic structural components of [PROTEINS]. (54)

Front 756

Figure 3.4 – Some of the different types of proteins. (a) _______: Globular proteins called _______ play a key role in many chemical reactions. (55)

Back 756

Some of the different types of proteins. (a) [ENZYMES]: Globular proteins called [ENZYMES] play a key role in many chemical reactions. (55)

Front 757

Figure 3.4 – Some of the different types of proteins. (b) _________ proteins: Red blood cells contain the protein hemoglobin, which transports oxygen and carbon dioxide in the body. (55)

Back 757

Figure 3.4 – Some of the different types of proteins. (b) [TRANSPORT proteins: Red blood cells contain the protein hemoglobin, which transports oxygen and carbon dioxide in the body. (55)

Front 758

Figure 3.4 – Some of the different types of proteins. (c) __________ proteins (collagen): Collagen is present in bones, tendons, and cartilage. (55)

Back 758

Figure 3.4 – Some of the different types of proteins. (c) [STRUCTURAL] proteins (collagen): Collagen is present in bones, tendons, and cartilage. (55)

Front 759

Figure 3.4 – Some of the different types of proteins. (d) __________ proteins (keratin): Keratin forms hair, nails, feathers, and components of horns. (55)

Back 759

Figure 3.4 – Some of the different types of proteins. (d) [STRUCTURAL] proteins (keratin): Keratin forms hair, nails, feathers, and components of horns. (55)

Front 760

Figure 3.4 – Some of the different types of proteins. (e) _________ proteins: White blood cells destroy cells without the proper identity proteins and make antibody proteins that attack invaders. (55)

Back 760

Figure 3.4 – Some of the different types of proteins. (e) [DEFENSIVE] proteins: White blood cells destroy cells without the proper identity proteins and make antibody proteins that attack invaders. (55)

Front 761

Figure 3.4 – Some of the different types of proteins. (f) ___________ proteins: Proteins called actin and myosin are present in muscles. (55)

Back 761

Figure 3.4 – Some of the different types of proteins. (f) [CONTRACTILE] proteins: Proteins called actin and myosin are present in muscles. (55)

Front 762

Some proteins form ____, ____ fibers, whereas others are globular, their strands ______ __ and folded back on themselves. (56)

Back 762

Some proteins form [LONG, THIN] fibers, whereas others are globular, their strands [COILED UP] and folded back on themselves. (56)

Front 763

The _____ of a protein is very important because it determines the protein’s function. There are four general levels of protein structure: primary, secondary, tertiary, and quaternary; all are ultimately determined by the ________ of amino acids. (56)

Back 763

The [SHAPE] of a protein is very important because it determines the protein’s function. There are four general levels of protein structure: primary, secondary, tertiary, and quaternary; all are ultimately determined by the [SEQUENCE] of amino acids. (56)

Front 764

Primary Structure – The sequence of amino acids of a ___________ chain is termed the ___________’_ primary structure. (56)

Back 764

Primary Structure – The sequence of amino acids of a [POLYPEPTIDE] chain is termed the [POLYPEPTIDE’S] primary structure. (56)

Front 765

The amino acids are linked together by _______ bonds, forming long chains like a “beaded strand.” (56)

Back 765

The amino acids are linked together by [PEPTIDE] bonds, forming long chains like a “beaded strand.” (56)

Front 766

The primary structure of a protein, the ________ of its amino acids, determines all other levels of protein structure. (56)

Back 766

The primary structure of a protein, the [SEQUENCE] of its amino acids, determines all other levels of protein structure. (56)

Front 767

Because amino acids can be assembled in any ________, a great diversity of proteins is possible. (56)

Back 767

Because amino acids can be assembled in any [SEQUENCE], a great diversity of proteins is possible. (56)

Front 768

Secondary Structure – Hydrogen bonds forming between different parts of the polypeptide chain _________ the folding of the polypeptide. As you can see, these ___________ hydrogen bonds, indicated by red dotted lines, do not involve the R groups themselves but rather the polypeptide backbone. This initial folding is called the secondary structure of a protein. (56)

Back 768

Secondary Structure – Hydrogen bonds forming between different parts of the polypeptide chain [STABILIZE] the folding of the polypeptide. As you can see, these [STABILIZING] hydrogen bonds, indicated by red dotted lines, do not involve the R groups themselves but rather the polypeptide backbone. This initial folding is called the secondary structure of a protein. (56)

Front 769

Hydrogen bonding within this secondary structure can fold the polypeptide into _____, called α-helices, and ______, called β-pleated sheets. (56)

Back 769

Hydrogen bonding within this secondary structure can fold the polypeptide into [COILS], called α-helices, and [SHEETS], called β-pleated sheets. (56)

Front 770

________ Structure – Because some of the amino acids are nonpolar, a polypeptide chain folds up in water, which is very polar, pushing nonpolar amino acid functional groups from the watery environment. (56)

Back 770

[TERTIARY] Structure – Because some of the amino acids are nonpolar, a polypeptide chain folds up in water, which is very polar, pushing nonpolar amino acid functional groups from the watery environment. (56)

Front 771

The final three-dimensional shape, or tertiary structure, of the protein, folded and twisted in the case of a globular molecule, is determined by exactly _____ in a polypeptide chain the nonpolar amino acids occur. (56)

Back 771

The final three-dimensional shape, or tertiary structure, of the protein, folded and twisted in the case of a globular molecule, is determined by exactly [WHERE] in a polypeptide chain the nonpolar amino acids occur. (56)

Front 772

Quaternary Structure – When a protein is composed of more than ___ polypeptide chain, the spatial arrangement of the several _________ chains is called the quaternary structure of the protein. For example, four subunits make up the quaternary structure of the protein hemoglobin. (56)

Back 772

Quaternary Structure – When a protein is composed of more than [ONE] polypeptide chain, the spatial arrangement of the several [COMPONENT] chains is called the quaternary structure of the protein. For example, four subunits make up the quaternary structure of the protein hemoglobin. (56)

Front 773

The _____ nature of the watery environment in the cell influences how the polypeptide folds into the functional protein. A protein is folded in such a way that allows it to carry out its ________. (57)

Back 773

The [POLAR] nature of the watery environment in the cell influences how the polypeptide folds into the functional protein. A protein is folded in such a way that allows it to carry out its [FUNCTION]. (57)

Front 774

If the polar nature of the protein’s environment changes by either increasing ___________ or lowering __, both of which alter hydrogen bonding, the protein may unfold, as in the lower right of the figure. When this happens the protein is said to be _________. (57)

Back 774

If the polar nature of the protein’s environment changes by either increasing [TEMPERATURE] or lowering [pH], both of which alter hydrogen bonding, the protein may unfold, as in the lower right of the figure. When this happens the protein is said to be [DENATURED]. (57)

Front 775

When the _____ nature of the solvent is reestablished, some proteins may spontaneously refold. When proteins are denatured, they usually lose their ability to ________ properly. That is the rationale behind traditional methods of salt-curing and pickling food. (57)

Back 775

When the [POLAR] nature of the solvent is reestablished, some proteins may spontaneously refold. When proteins are denatured, they usually lose their ability to [FUNCTION] properly. That is the rationale behind traditional methods of salt-curing and pickling food. (57)

Front 776

Prior to the ready availability of refrigerators and freezers, the only practical way to keep microorganisms from growing in food was top keep the food in a solution containing a high concentration of salt or vinegar, which _________ proteins in the microorganisms and kept them from growing on the food. (57)

Back 776

Prior to the ready availability of refrigerators and freezers, the only practical way to keep microorganisms from growing in food was top keep the food in a solution containing a high concentration of salt or vinegar, which [DENATURED] proteins in the microorganisms and kept them from growing on the food. (57)

Front 777

Because the primary structure of a protein, its ________ of amino acids, determines how the protein folds into its functional shape, a change in the identity of even one _____ ____ can have profound effects on a protein’s ability to function properly. (57)

Back 777

Because the primary structure of a protein, its [SEQUENCE] of amino acids, determines how the protein folds into its functional shape, a change in the identity of even one [AMINO ACID] can have profound effects on a protein’s ability to function properly. (57)

Front 778

_______ are globular proteins that have three-dimensional shapes. (57)

Back 778

[ENZYMES] are globular proteins that have three-dimensional shapes. (57)

Front 779

For enzymes to function properly, they need to ____ correctly. (57)

Back 779

For enzymes to function properly, they need to [FOLD] correctly. (57)

Front 780

Enzymes have grooves or depressions that precisely fit a particular sugar or other chemical (like the red molecule binding to the enzyme to the right); once in the groove, the chemical is encouraged to undergo a ________ – often, one of its chemical bonds is stressed as the chemical is bent by the enzyme, like a foot in a flexing shoe. This process of enhancing chemical reactions is called _________, and proteins are the catalytic agents of cells, determining what chemical processes take place and where and when. (57)

Back 780

Enzymes have grooves or depressions that precisely fit a particular sugar or other chemical (like the red molecule binding to the enzyme to the right); once in the groove, the chemical is encouraged to undergo a [REACTION] – often, one of its chemical bonds is stressed as the chemical is bent by the enzyme, like a foot in a flexing shoe. This process of enhancing chemical reactions is called [CATALYSIS], and proteins are the catalytic agents of cells, determining what chemical processes take place and where and when. (57)

Front 781

Many structural proteins form long cables that have architectural roles in cells, providing ________ and determining _____. Cells contain a network of protein cables that maintain the shape of the cell and function in ____________ materials throughout the cell (figure 3.7). (57)

Back 781

Many structural proteins form long cables that have architectural roles in cells, providing [STRENGTH] and determining [SHAPE]. Cells contain a network of protein cables that maintain the shape of the cell and function in [TRANSPORTING] materials throughout the cell (figure 3.7). (57)

Front 782

___________ proteins function in muscle contraction, which is the shortening of a muscle. (57)

Back 782

[CONTRACTILE] proteins function in muscle contraction, which is the shortening of a muscle. (57)

Front 783

A muscle ________ when two proteins that are anchored on opposite ends of a muscle fiber slide past each other, bringing the ends of the fiber closer together. (57)

Back 783

A muscle [SHORTENS] when two proteins that are anchored on opposite ends of a muscle fiber slide past each other, bringing the ends of the fiber closer together. (57)

Front 784

Figure 3.7 – Protein structure determines ________. Fluorescently labeled structural proteins within a cell. (57)

Back 784

Figure 3.7 – Protein structure determines [FUNCTION]. Fluorescently labeled structural proteins within a cell. (57)

Front 785

How does a protein fold into a specific shape? As just discussed, ________ amino acids play a key role. Until recently, investigators thought that newly made proteins fold spontaneously as hydrophobic interactions with water shove nonpolar amino acids into the protein interior. We now know this is too simple a view. Proteins can fold into many different ways that trial and error would simply take too long. In addition, as the open chain folds its way toward its final form, ________ “sticky” interior portions are exposed during intermediate stages. If these intermediate forms are placed in a test tube in the same protein environment that occurs in a cell, they stick to other unwanted protein partners, forming a gluey mess. (58)

Back 785

How does a protein fold into a specific shape? As just discussed, [NONPOLAR] amino acids play a key role. Until recently, investigators thought that newly made proteins fold spontaneously as hydrophobic interactions with water shove nonpolar amino acids into the protein interior. We now know this is too simple a view. Proteins can fold into many different ways that trial and error would simply take too long. In addition, as the open chain folds its way toward its final form, [NONPOLAR] “sticky” interior portions are exposed during intermediate stages. If these intermediate forms are placed in a test tube in the same protein environment that occurs in a cell, they stick to other unwanted protein partners, forming a gluey mess. (58)

Front 786

How do cells avoid this? A vital clue came in studies of unusual _________ (changes in DNA) that prevented viruses from replicating in bacterial cells – it turned out the virus proteins could not fold properly! Further study revealed that normal cells contain special proteins called chaperone proteins that help new proteins fold correctly. When the bacterial gene encoding its chaperone protein is disabled by ________, the bacteria die, clogged with lumps of incorrectly folded proteins. Fully 30% of the bacteria’s proteins fail to fold into the right shape. (58)

Back 786

How do cells avoid this? A vital clue came in studies of unusual [MUTATIONS] (changes in DNA) that prevented viruses from replicating in bacterial cells – it turned out the virus proteins could not fold properly! Further study revealed that normal cells contain special proteins called chaperone proteins that help new proteins fold correctly. When the bacterial gene encoding its chaperone protein is disabled by [MUTATION], the bacteria die, clogged with lumps of incorrectly folded proteins. Fully 30% of the bacteria’s proteins fail to fold into the right shape. (58)

Front 787

Molecular biologists have now identified more than 17 kinds of proteins that act as molecular __________. Many are heat shock proteins, produced in greater amounts if a cell is exposed to elevated temperature; high temperatures cause proteins to unfold, and heat shock _________ proteins help the cell’s proteins refold. (58)

Back 787

Molecular biologists have now identified more than 17 kinds of proteins that act as molecular [CHAPERONES]. Many are heat shock proteins, produced in greater amounts if a cell is exposed to elevated temperature; high temperatures cause proteins to unfold, and heat shock [CHAPERONE] proteins help the cell’s proteins refold. (58)

Front 788

To understand how a _________ works, examine figure 3.8 closely. The misfolded protein enters inside the _________. There, in a way not clearly understood, the visiting protein is induced to unfold and then refold again, before it leaves. You can see in the third panel of the diagram the protein has unfolded into a long polypeptide chain. In the fourth panel, the polypeptide chain has then refolded into a different shape. The _________ protein has in this way “rescued” a protein that was caught in a wrongly folded state and given it another chance to fold correctly. To demonstrate this rescue capability, investigators “fed” a deliberately misfolded protein malate dehydrogenase to _________ proteins; the malate dehydrogenase was rescued, refolding to its active shape. (58)

Back 788

To understand how a [CHAPERONE] works, examine figure 3.8 closely. The misfolded protein enters inside the [CHAPERONE]. There, in a way not clearly understood, the visiting protein is induced to unfold and then refold again, before it leaves. You can see in the third panel of the diagram the protein has unfolded into a long polypeptide chain. In the fourth panel, the polypeptide chain has then refolded into a different shape. The [CHAPERONE] protein has in this way “rescued” a protein that was caught in a wrongly folded state and given it another chance to fold correctly. To demonstrate this rescue capability, investigators “fed” a deliberately misfolded protein malate dehydrogenase to [CHAPERONE] proteins; the malate dehydrogenase was rescued, refolding to its active shape. (58)

Front 789

There are tantalizing suggestions that chaperone protein deficiencies may play a role in _________’_ disease. By failing to facilitate the intricate folding of key proteins, the deficiency leads to the amyloid protein clumping in brain cells characteristic of the disease. ___ ___ disease and the similar human disorder called variant ___________-_____ disease are both caused by misfolded brain proteins called prions. The misfolded prions induce other brain prion proteins to misfold in turn, creating a chain reaction of misfolding that kills ever more brain cells, leading to progressive loss of brain function and eventual death. (58)

Back 789

There are tantalizing suggestions that chaperone protein deficiencies may play a role in [ALZHEIMER’S] disease. By failing to facilitate the intricate folding of key proteins, the deficiency leads to the amyloid protein clumping in brain cells characteristic of the disease. [MAD COW] disease and the similar human disorder called variant [CREUTZFELDT-JACOB] disease are both caused by misfolded brain proteins called prions. The misfolded prions induce other brain prion proteins to misfold in turn, creating a chain reaction of misfolding that kills ever more brain cells, leading to progressive loss of brain function and eventual death. (58)

Front 790

Key Learning Outcome 3.2 – Proteins are made up of chains of amino acids that ____ into complex shapes. The sequence of its amino acids determines a protein’s function. Chaperone proteins help newly produced proteins to ____ properly. (58)

Back 790

Key Learning Outcome 3.2 – Proteins are made up of chains of amino acids that [FOLD] into complex shapes. The sequence of its amino acids determines a protein’s function. Chaperone proteins help newly produced proteins to [FOLD] properly. (58)

Front 791

Figure 3.8 – How one type of chaperone protein works. This barrel-shaped chaperone protein is a ____ _____ protein, produced in elevated amounts at high temperature. An incorrectly folded protein enters one chamber of the barrel, and a cap seals the chamber and confines the protein. The isolated protein is now prevented from aggregating with other misfolded proteins, and it has a chance to refold properly. After a short time, the protein is ejected, folded or unfolded, and the cycle can repeat itself. (58)

Back 791

Figure 3.8 – How one type of chaperone protein works. This barrel-shaped chaperone protein is a [HEAT SHOCK] protein, produced in elevated amounts at high temperature. An incorrectly folded protein enters one chamber of the barrel, and a cap seals the chamber and confines the protein. The isolated protein is now prevented from aggregating with other misfolded proteins, and it has a chance to refold properly. After a short time, the protein is ejected, folded or unfolded, and the cycle can repeat itself. (58)

Front 792

Prions and Mad Cow Disease – For decades, scientists have been fascinated by a peculiar group of fatal brain diseases. These diseases have the unusual property that they are transmissible from one individual to another, but it is years and often decades before the disease is detected in infected individuals. The brains of these individuals develop numerous small cavities as neurons die, producing a marked spongy appearance, as shown here in the photo. Called _____________ __________ ________________ (TSEs), these diseases include scrapie in sheep, “mad cow” disease in cattle, and kuru and Creutzfeldt-Jakob disease in humans. (59)

Back 792

Prions and Mad Cow Disease – For decades, scientists have been fascinated by a peculiar group of fatal brain diseases. These diseases have the unusual property that they are transmissible from one individual to another, but it is years and often decades before the disease is detected in infected individuals. The brains of these individuals develop numerous small cavities as neurons die, producing a marked spongy appearance, as shown here in the photo. Called [TRANSMISSIBLE SPONGIFORM ENCEPHALOPATHIES] (TSEs), these diseases include scrapie in sheep, “mad cow” disease in cattle, and kuru and Creutzfeldt-Jakob disease in humans. (59)

Front 793

Prions and Mad Cow Disease – TSEs can be transmitted between individuals of a _______ by injecting infected brain tissue into a recipient animal’s brain. TSEs can also spread via tissue transplants and, apparently, food. Kuru was common in the Fore people of Papua New Guinea when they practiced ritual cannibalism, literally eating the brains of infected individuals. Mad cow disease spread widely among the cattle herds of England in the 1990s because cows were fed bone meal prepared from sheep carcasses to increase the protein content of their diet. Like the Fore, the British cattle were literally eating the tissue of sheep that had died of scrapie. (59)

Back 793

Prions and Mad Cow Disease – TSEs can be transmitted between individuals of a [SPECIES] by injecting infected brain tissue into a recipient animal’s brain. TSEs can also spread via tissue transplants and, apparently, food. Kuru was common in the Fore people of Papua New Guinea when they practiced ritual cannibalism, literally eating the brains of infected individuals. Mad cow disease spread widely among the cattle herds of England in the 1990s because cows were fed bone meal prepared from sheep carcasses to increase the protein content of their diet. Like the Fore, the British cattle were literally eating the tissue of sheep that had died of scrapie. (59)

Front 794

Prions and Mad Cow Disease – In the 1960s, British researchers T. _____ and J. ________ noted that infectious TSE preparations remained infectious even after exposure to radiation that would destroy DNA or RNA. They suggested that the infectious agent was a protein. Perhaps, they speculated, the protein usually preferred one folding pattern but could sometimes misfold and then ________ other proteins to do the same, the misfolding spreading like a chain reaction. This heretical suggestion was not accepted by the scientific community, as it violates a key tenet of molecular biology: only DNA or RNA act as hereditary material, transmitting information from one generation to the next. (59)

Back 794

Prions and Mad Cow Disease – In the 1960s, British researchers T. [ALPER] and J. [GRIGGITH] noted that infectious TSE preparations remained infectious even after exposure to radiation that would destroy DNA or RNA. They suggested that the infectious agent was a protein. Perhaps, they speculated, the protein usually preferred one folding pattern but could sometimes misfold and then [CATALYZE] other proteins to do the same, the misfolding spreading like a chain reaction. This heretical suggestion was not accepted by the scientific community, as it violates a key tenet of molecular biology: only DNA or RNA act as hereditary material, transmitting information from one generation to the next. (59)

Front 795

Prions and Mad Cow Disease – In the early 1970s, physician Stanley ________, moved by the death of a patient from Creutzfeldt-Jakob disease, began to study TSEs. ________ became fascinated with Alper and Griffith’s hypothesis. Try as he might, ________ could find no evidence of nucleic acids, bacteria, or viruses in the infectious TSE preparation. He concluded, as Alper and Griffith had, that the infectious agent was a protein, which he named a prion, for “proteinaceous infectious particle.” (59)

Back 795

Prions and Mad Cow Disease – In the early 1970s, physician Stanley [PRUSINER], moved by the death of a patient from Creutzfeldt-Jakob disease, began to study TSEs. [PRUSINER] became fascinated with Alper and Griffith’s hypothesis. Try as he might, [PRUSINER] could find no evidence of nucleic acids, bacteria, or viruses in the infectious TSE preparation. He concluded, as Alper and Griffith had, that the infectious agent was a protein, which he named a prion, for “proteinaceous infectious particle.” (59)

Front 796

Prions and Mad Cow Disease – Prusiner went on to [ISOLATE] a distinctive prion protein, and for two decades, he continued to amass evidence that prions play a key role in triggering TSEs. The scientific community resisted Prusiner’s renegade conclusions, but eventually experiments done in Prusiner’s and other laboratories began to convince many. For example, when Prusiner injected prions of different abnormal conformations into several different hosts, these hosts developed prions with the same abnormal conformations as the parent prions. In another important experiment, Charles Weissmann showed that mice genetically engineered to lack Prusiner’s prion protein are immune to TSE infection. However, if brain tissue with the prion protein is grafted into the mice, the grafted tissue – but not the rest of the brain – can then be infected with TSE. In 1997, Prusiner was awarded the Nobel Prize in Physiology or Medicine for his work on prions. (59)

Back 796

Prions and Mad Cow Disease – Prusiner went on to [ISOLATE] a distinctive prion protein, and for two decades, he continued to amass evidence that prions play a key role in triggering TSEs. The scientific community resisted Prusiner’s renegade conclusions, but eventually experiments done in Prusiner’s and other laboratories began to convince many. For example, when Prusiner injected prions of different abnormal conformations into several different hosts, these hosts developed prions with the same abnormal conformations as the parent prions. In another important experiment, Charles Weissmann showed that mice genetically engineered to lack Prusiner’s prion protein are immune to TSE infection. However, if brain tissue with the prion protein is grafted into the mice, the grafted tissue – but not the rest of the brain – can then be infected with TSE. In 1997, Prusiner was awarded the Nobel Prize in Physiology or Medicine for his work on prions. (59)

Front 797

Prions and Mad Cow Disease – Can Humans Catch Mad Cow Disease by Eating Infected Meat? – Many scientists are becoming worried that ______ may be transmitting such diseases to humans. Specifically, they worry that _____-caused bovine spongiform encephalopathy (BSE), a brain disease in cows commonly known as mad cow disease, may infect humans and produce a similar fatal disorder, variant Creutzfeldt-Jakob disease (vCJD). (59)

Back 797

Prions and Mad Cow Disease – Can Humans Catch Mad Cow Disease by Eating Infected Meat? – Many scientists are becoming worried that [PRIONS] may be transmitting such diseases to humans. Specifically, they worry that [PRION]-caused bovine spongiform encephalopathy (BSE), a brain disease in cows commonly known as mad cow disease, may infect humans and produce a similar fatal disorder, variant Creutzfeldt-Jakob disease (vCJD). (59)

Front 798

In March 1996, an outbreak of ___ ___ _______ in Britain, with over 80,000 cows infected, created widespread concern. BSE, a degeneration of the brain caused by prions, appears to have entered the British cattle herds from sheep! Sheep are subject to a prion disease called scrapie, and the disease is thought to have passed from sheep to cows through protein-supplemented feed pellets containing ground-up sheep brains. (59)

Back 798

In March 1996, an outbreak of [MAD COW DISEASE] in Britain, with over 80,000 cows infected, created widespread concern. BSE, a degeneration of the brain caused by prions, appears to have entered the British cattle herds from sheep! Sheep are subject to a prion disease called scrapie, and the disease is thought to have passed from sheep to cows through protein-supplemented feed pellets containing ground-up sheep brains. (59)

Front 799

The passage of prions from one species to another has a scary consequence: prions can also pass from ____ to ______! At least 148 British consumers of BSE-infected beef have subsequently died of vCJD. Tissue from the brains of the dead Britons and from BSE cows induce the same brain lesions in mice, while classic CJD produces quite different lesions – clearly the form of vCJD that killed them was caused by the same agent that caused BSE. (59)

Back 799

The passage of prions from one species to another has a scary consequence: prions can also pass from [COWS] to [PEOPLE]! At least 148 British consumers of BSE-infected beef have subsequently died of vCJD. Tissue from the brains of the dead Britons and from BSE cows induce the same brain lesions in mice, while classic CJD produces quite different lesions – clearly the form of vCJD that killed them was caused by the same agent that caused BSE. (59)

Front 800

Prions and Mad Cow Disease – Can Humans Catch Mad Cow Disease by Eating Infected Meat? – The occasional appearance of BSE-infected cows in ________ and ______ ______ herds has led to heightened scrutiny of commercial beef in the United States in an attempt to eliminate any possibility of BSE contamination. (59)

Back 800

Prions and Mad Cow Disease – Can Humans Catch Mad Cow Disease by Eating Infected Meat? – The occasional appearance of BSE-infected cows in [CANADIAN] and [UNITED STATES] herds has led to heightened scrutiny of commercial beef in the United States in an attempt to eliminate any possibility of BSE contamination. (59)

Front 801

Very long polymers called nucleic acids serve as the ___________ storage devices of cells, just as DVDs or hard drives store the information that computers use. (60)

Back 801

Very long polymers called nucleic acids serve as the [INFORMATION] storage devices of cells, just as DVDs or hard drives store the information that computers use. (60)

Front 802

Nucleic acids are long ________ of repeating subunits called nucleotides. (60)

Back 802

Nucleic acids are long [POLYMERS] of repeating subunits called nucleotides. (60)

Front 803

Each __________ is a complex organic molecule composed of three parts shown in figure 3.9a: a five-carbon sugar (in blue), a phosphate group (in yellow, PO4), and an organic nitrogen-containing base (in orange). In the formation of a nucleic acid, the individual sugars with their attached nitrogenous bases are linked in a line by the phosphate groups in very long ______________ chains (shown to the right). (60)

Back 803

Each [NUCLEOTIDE] is a complex organic molecule composed of three parts shown in figure 3.9a: a five-carbon sugar (in blue), a phosphate group (in yellow, PO4), and an organic nitrogen-containing base (in orange). In the formation of a nucleic acid, the individual sugars with their attached nitrogenous bases are linked in a line by the phosphate groups in very long [POLYNUCLEOTIDE] chains (shown to the right). (60)

Front 804

How does the long, chainlike structure of a _______ ____ permit it to store the information necessary to specify what a human being is like? If _______ _____ were simply a monotonous repeating polymer, it could not encode the message of life. Imagine trying to write a story using only the letter E and no spaces or punctuation. All you could ever say is “EEEEEEEE….” You need more than one letter to communicate – the English alphabet uses 26 letters. (60)

Back 804

How does the long, chainlike structure of a [NUCLEIC ACID] permit it to store the information necessary to specify what a human being is like? If [NUCLEIC ACIDS] were simply a monotonous repeating polymer, it could not encode the message of life. Imagine trying to write a story using only the letter E and no spaces or punctuation. All you could ever say is “EEEEEEEE….” You need more than one letter to communicate – the English alphabet uses 26 letters. (60)

Front 805

_______ _____ can encode information because they contain more than one kind of nucleotide. There are five different kinds of nucleotides: two larger ones that contain the nitrogenous bases _______ and _______ (shown in the top row of figure 3.9b), and three smaller ones that contain the nitrogenous bases ________, _______, and ______ (in the bottom row). (60)

Back 805

[NUCLEIC ACIDS] can encode information because they contain more than one kind of nucleotide. There are five different kinds of nucleotides: two larger ones that contain the nitrogenous bases [ADENINE] and [GUANINE] (shown in the top row of figure 3.9b), and three smaller ones that contain the nitrogenous bases [CYTOSINE], [THYMINE], and [URACIL] (in the bottom row). (60)

Front 806

Nucleic acids encode information by varying the ________ of the nucleotide at each position in the polymer. (60)

Back 806

Nucleic acids encode information by varying the [IDENTITY] of the nucleotide at each position in the polymer. (60)

Front 807

Nucleic acids come in two varieties, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both ________ of nucleotides with some differences. (60)

Back 807

Nucleic acids come in two varieties, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA), both [POLYMERS] of nucleotides with some differences. (60)

Front 808

RNA is similar to DNA but with two major chemical differences. First, RNA molecules contain the sugar ______, in which the 2’carbon (this is the carbon labeled 2’ in figure 3.9a) is bonded to a hydroxyl group (-OH). In DNA, this hydroxyl group is replaced with a ________ ____. Second, RNA molecules do not contain the _______ nucleotide; they contain ______ instead. Structurally, RNA is also different. RNA is a long, single strand of nucleotides and is used by cells in making proteins using genetic instructions encoded within DNA. (60)

Back 808

RNA is similar to DNA but with two major chemical differences. First, RNA molecules contain the sugar [RIBOSE], in which the 2’carbon (this is the carbon labeled 2’ in figure 3.9a) is bonded to a hydroxyl group (-OH). In DNA, this hydroxyl group is replaced with a [HYDROGEN ATOM]. Second, RNA molecules do not contain the [THYMINE] nucleotide; they contain [URACIL] instead. Structurally, RNA is also different. RNA is a long, single strand of nucleotides and is used by cells in making proteins using genetic instructions encoded within DNA. (60)

Front 809

The ________ of nucleotides in DNA determines the order of amino acids in the _______ structure of the protein. (60)

Back 809

The [SEQUENCE] of nucleotides in DNA determines the order of amino acids in the [PRIMARY] structure of the protein. (60)

Front 810

DNA consists of two polynucleotide chains would around each other in a ______ _____, like strands of a pearl necklace twisted together. You can see this difference in structure by comparing the blue double-stranded DNA molecule in figure 3.10 with the green single-stranded RNA molecule. (61)

Back 810

DNA consists of two polynucleotide chains would around each other in a [DOUBLE HELIX], like strands of a pearl necklace twisted together. You can see this difference in structure by comparing the blue double-stranded DNA molecule in figure 3.10 with the green single-stranded RNA molecule. (61)

Front 811

Figure 3.9 – The structure of a nucleotide. (a) Nucleotides are composed of three parts: a ____-______ _____, a _________ _____, and an organic ___________ ____. (b) The ___________ ____ can be one of five. (60)

Back 811

Figure 3.9 – The structure of a nucleotide. (a) Nucleotides are composed of three parts: a [FIVE-CARBON SUGAR], a [PHOSPHATE GROUP], and an organic [NITROGENOUS BASE]. (b) The [NITROGENOUS BASE] can be one of five. (60)

Front 812

Figure 3.10 – How DNA structure differs from RNA. (a) DNA contains two ______________ strands wrapped around each other, while (b) RNA is ______-________. (60)

Back 812

Figure 3.10 – How DNA structure differs from RNA. (a) DNA contains two [POLYNUCLEOTIDE] strands wrapped around each other, while (b) RNA is [SINGLE-STRANDED]. (60)

Front 813

Why is DNA a double helix? When scientists looked carefully at the structure of the DNA double helix, they found that the bases of each chain point ______ toward the other (like the DNA strands shown in figure 3.11). The bases of the two chains are linked in the middle of the molecule by ________ _____ (the dotted lines between the two strands), like two columns of people holding hands across. (61)

Back 813

Why is DNA a double helix? When scientists looked carefully at the structure of the DNA double helix, they found that the bases of each chain point [INWARD] toward the other (like the DNA strands shown in figure 3.11). The bases of the two chains are linked in the middle of the molecule by [HYDROGEN BONDS] (the dotted lines between the two strands), like two columns of people holding hands across. (61)

Front 814

The key to understanding why DNA is a ______ _____ is revealed by looking at the bases: only two base pairs are possible. Because the distance between the two strands is __________, this suggests that two big bases cannot ____ together – the combination is simply too bulky to fit; similarly, two little ones cannot pair, as they pinch the helix inward too much. (61)

Back 814

The key to understanding why DNA is a [DOUBLE HELIX] is revealed by looking at the bases: only two base pairs are possible. Because the distance between the two strands is [CONSISTENT], this suggests that two big bases cannot [PAIR] together – the combination is simply too bulky to fit; similarly, two little ones cannot pair, as they pinch the helix inward too much. (61)

Front 815

To form a double helix, it is necessary to pair a ___ ____ with a ______ one. In every DNA double helix, adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C). The reason A doesn’t pair with C and G doesn’t pair with T is that these base pairs cannot form proper ________ _____ – the electron-sharing atoms are not aligned with each other. (61)

Back 815

To form a double helix, it is necessary to pair a [BIG BASE] with a [LITTLE] one. In every DNA double helix, adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C). The reason A doesn’t pair with C and G doesn’t pair with T is that these base pairs cannot form proper [HYDROGEN BONDS] – the electron-sharing atoms are not aligned with each other. (61)

Front 816

The simple A-T, G-C base pairs within the DNA double helix allow the cell to ____ the information in a very simple way. It just unzips the helix and adds the complementary bases to each new strand! That is the great advantage of a double helix – it actually contains two copies of the information, one the mirror image of the other. If the sequence of one chain is ATTGCAT, the sequence of its partner in the double helix must be TAACGTA. The fidelity with which hereditary information is passed from one generation to the next is a direct result of this simple double-entry bookkeeping. (61)

Back 816

The simple A-T, G-C base pairs within the DNA double helix allow the cell to [COPY] the information in a very simple way. It just unzips the helix and adds the complementary bases to each new strand! That is the great advantage of a double helix – it actually contains two copies of the information, one the mirror image of the other. If the sequence of one chain is ATTGCAT, the sequence of its partner in the double helix must be TAACGTA. The fidelity with which hereditary information is passed from one generation to the next is a direct result of this simple double-entry bookkeeping. (61)

Front 817

Figure 3.11 – The DNA double helix. The DNA molecule is composed of two ______________ chains twisted together to form a double helix. The two chains of the double helix are joined by ________ _____ between the A-T and G-C base pairs. The section of DNA on the upper right is a space-filling model of DNA, where atoms are indicated by colored balls. (61)

Back 817

Figure 3.11 – The DNA double helix. The DNA molecule is composed of two [POLYNUCLEOTIDE] chains twisted together to form a double helix. The two chains of the double helix are joined by [HYDROGEN BONDS] between the A-T and G-C base pairs. The section of DNA on the upper right is a space-filling model of DNA, where atoms are indicated by colored balls. (61)

Front 818

Key Learning Outcome 3.3 – _______ acids like DNA are composed of long chains of nucleotides. The sequence of the nucleotides specifies the _____ acid sequence of proteins. (61)

Back 818

Key Learning Outcome 3.3 – [NUCLEIC] acids like DNA are composed of long chains of nucleotides. The sequence of the nucleotides specifies the [AMINO] acid sequence of proteins. (61)

Front 819

Polymers called _____________ make up the structural framework of cells and play a critical role in ______ storage. (63)

Back 819

[POLYMERS] called carbohydrates make up the structural framework of cells and play a critical role in [ENERGY] storage. (63)

Front 820

A carbohydrate is any molecule that contains ______, ________, and ______ in the ratio 1:2:1. (63)

Back 820

A carbohydrate is any molecule that contains carbon, hydrogen, and oxygen in the ratio 1:2:1. (63)

Front 821

Because they contain many carbon-hydrogen (C-H) bonds, carbohydrates are well-suited for ______ _______. Such C-H bonds are the ones most often broken by organisms to obtain ______. Table 3.2 on the following page shows some examples of carbohydrates. (63)

Back 821

Because they contain many carbon-hydrogen (C-H) bonds, carbohydrates are well-suited for [ENERGY STORAGE]. Such C-H bonds are the ones most often broken by organisms to obtain [Energy]. Table 3.2 on the following page shows some examples of carbohydrates. (63)

Front 822

The simplest carbohydrates are the simple sugars or _______________ (from the Greek monos, single, and saccharin, sweet). These molecules consist of one subunit. For example, glucose, the sugar that carries energy to the cells of your body, is made of chain of six carbons and has the chemical formula C6H12O6 (figure 3.12). When placed in water, the chain folds into the ring structure shown on the lower right of the figure. The individual atoms are depicted in the “3-D” space-filling model you see in the lower left of the figure. (63)

Back 822

The simplest carbohydrates are the simple sugars or [MONOSACCHARIDES] (from the Greek monos, single, and saccharin, sweet). These molecules consist of one subunit. For example, glucose, the sugar that carries energy to the cells of your body, is made of chain of six carbons and has the chemical formula C6H12O6 (figure 3.12). When placed in water, the chain folds into the ring structure shown on the lower right of the figure. The individual atoms are depicted in the “3-D” space-filling model you see in the lower left of the figure. (63)

Front 823

Another type of simple carbohydrate is a ____________, which forms when two monosaccharides link together through a dehydration reaction. In figure 3.13, you can see how the ____________ sucrose (table sugar) is made by linking two six-carbon sugars together, a glucose (orange) and a fructose (green). (63)

Back 823

Another type of simple carbohydrate is a [DISACCHARIDE], which forms when two monosaccharides link together through a dehydration reaction. In figure 3.13, you can see how the [DISACCHARIDE] sucrose (table sugar) is made by linking two six-carbon sugars together, a glucose (orange) and a fructose (green). (63)

Front 824

Organisms store their metabolic energy by __________ sugars, which are soluble, into insoluble forms that can be deposited in specific storage areas in the body. This trick is achieved by linking the sugars together into long polymer chains called _______________. (63)

Back 824

Organisms store their metabolic energy by [CONVERTING] sugars, which are soluble, into insoluble forms that can be deposited in specific storage areas in the body. This trick is achieved by linking the sugars together into long polymer chains called [POLYSACCHARIDES]. (63)

Front 825

Plants and animals store energy in polysaccharides formed from glucose. The glucose polysaccharide that plants use to store energy is called ______. In animals, energy is stored in ________, an insoluble macromolecule formed of long glucose polysaccharides that are highly branched. (63)

Back 825

Plants and animals store energy in polysaccharides formed from glucose. The glucose polysaccharide that plants use to store energy is called [STARCH]. In animals, energy is stored in [GLYCOGEN], an insoluble macromolecule formed of long glucose polysaccharides that are highly branched. (63)

Front 826

Plants and animals also use _______ chains as building materials, linking the subunits together in different orientations not recognized by most enzymes. These structural polysaccharides are ______, in animals, and _________, in plants. (63)

Back 826

Plants and animals also use [GLUCOSE] chains as building materials, linking the subunits together in different orientations not recognized by most enzymes. These structural polysaccharides are [CHITIN], in animals, and [CELLULOSE], in plants. (63)

Front 827

The cellulose deposited in the ____ _____ of plant cells, like the cellulose strand shown in figure 3.14, cannot be ________ by humans and makes up the fiber in our diets. (63)

Back 827

The cellulose deposited in the [CELL WALLS] of plant cells, like the cellulose strand shown in figure 3.14, cannot be [DIGESTED] by humans and makes up the fiber in our diets. (63)

Front 828

Key Learning Outcome 3.4 – _____________ are molecules made of C, H, and O atoms. As sugars they store energy in C-H bonds, and as long polysaccharide chains they can provide __________ support. (63)

Back 828

Key Learning Outcome 3.4 – [CARBOHYDRATES] are molecules made of C, H, and O atoms. As sugars they store energy in C-H bonds, and as long polysaccharide chains they can provide [STRUCTURAL] support. (63)

Front 829

Figure 3.12 – The structure of glucose. Glucose is a ______________ and consists of linear six-carbon molecule that forms a ring when added to water. This illustration shows three ways glucose can be represented diagrammatically. (63)

Back 829

Figure 3.12 – The structure of glucose. Glucose is a [MONOSACCHARIDE] and consists of linear six-carbon molecule that forms a ring when added to water. This illustration shows three ways glucose can be represented diagrammatically. (63)

Front 830

Figure 3.13 – Formation of sucrose. The ____________ sucrose is formed from glucose and fructose in a dehydration reaction. (63)

Back 830

Figure 3.13 – Formation of sucrose. The [DISACCHARIDE] sucrose is formed from glucose and fructose in a dehydration reaction. (63)

Front 831

Figure 3.14 – A polysaccharide: cellulose. The polysaccharide cellulose is found in the cell walls of _____ _____ and is composed of glucose subunits. (63)

Back 831

Figure 3.14 – A polysaccharide: cellulose. The polysaccharide cellulose is found in the cell walls of [PLANT CELLS] and is composed of glucose subunits. (63)

Front 832

For ____-term energy storage, organisms usually convert glucose into ____, another kind of storage molecule that contains more energy-rich C-H bonds than carbohydrates. (65)

Back 832

For [LONG]-term energy storage, organisms usually convert glucose into [FATS], another kind of storage molecule that contains more energy-rich C-H bonds than carbohydrates. (65)

Front 833

Fats and all other biological molecules that are not soluble in _____ but are soluble in oil are called ______. (65)

Back 833

Fats and all other biological molecules that are not soluble in [WATER] but are soluble in oil are called [LIPIDS]. (65)

Front 834

Lipids are _________ in water not because they are long chains like starches but rather because they are nonpolar. In water, fat molecules cluster together because they cannot form ________ _____ with water molecules. This is why oil forms into a layer on top of water when the two substances are mixed. (65)

Back 834

Lipids are [INSOLUBLE] in water not because they are long chains like starches but rather because they are nonpolar. In water, fat molecules cluster together because they cannot form [HYDROGEN BONDS] with water molecules. This is why oil forms into a layer on top of water when the two substances are mixed. (65)

Front 835

Fat molecules are ______ composed of two kinds of subunits: _____ _____ (the gray boxed structures in figure 3.15a) and ________ (the orange boxed structure). (65)

Back 835

Fat molecules are [LIPIDS] composed of two kinds of subunits: [FATTY ACIDS] (the gray boxed structures in figure 3.15a) and [GLYCEROL] (the orange boxed structure). (65)

Front 836

A _____ ____ is a long chain of carbon and hydrogen atoms (called a hydrocarbon) ending in a carboxyl (-COOH) group. The three carbons of glycerol form the backbone to which three _____ _____ are attaching the dehydration reaction that forms the fat molecule. That is why the carboxyl groups of the _____ _____ in figure 3.15a are not apparent; they are involved in bonds with glycerol. Because it contains three _____ _____, the resulting fat molecule is sometimes called a triacylglycerol, or triglyceride. (65)

Back 836

A [FATTY ACID] is a long chain of carbon and hydrogen atoms (called a hydrocarbon) ending in a carboxyl (-COOH) group. The three carbons of glycerol form the backbone to which three [FATTY ACIDS] are attaching the dehydration reaction that forms the fat molecule. That is why the carboxyl groups of the [FATTY ACIDS] in figure 3.15a are not apparent; they are involved in bonds with glycerol. Because it contains three [FATTY ACIDS], the resulting fat molecule is sometimes called a triacylglycerol, or triglyceride. (65)

Front 837

Fatty acids with all internal carbon atoms forming covalent bonds with two hydrogen atoms contain the _______ number of hydrogen atoms. Fats composed of these fatty acids are said to be _________ (figure 3.15b). (65)

Back 837

Fatty acids with all internal carbon atoms forming covalent bonds with two hydrogen atoms contain the [MAXIMUM] number of hydrogen atoms. Fats composed of these fatty acids are said to be [SATURATED] (figure 3.15b). (65)

Front 838

Saturated fats are _____ at room temperature. On the other hand, fats composed of fatty acids that have double bonds between one or more pairs of carbon atoms contain fewer than the maximum number of hydrogen atoms and are called ___________ (figure 3.15c). The double bonds create kinks in the fatty acid tails, which usually makes the unsaturated fats ______ at room temperature. (65)

Back 838

Saturated fats are [SOLID] at room temperature. On the other hand, fats composed of fatty acids that have double bonds between one or more pairs of carbon atoms contain fewer than the maximum number of hydrogen atoms and are called [UNSATURATED] (figure 3.15c). The double bonds create kinks in the fatty acid tails, which usually makes the unsaturated fats [LIQUID] at room temperature. (65)

Front 839

Many _____ fats are unsaturated and occur as oils. ______ fats, in contrast, are often saturated and occur as hard fats. (65)

Back 839

Many [Plant] fats are unsaturated and occur as oils. [Animal] fats, in contrast, are often saturated and occur as hard fats. (65)

Front 840

In some cases, unsaturated fats in food products may be artificially ____________ (industrial addition of hydrogens) to make them more saturated, extending the shelf life of these products. In some cases, the _____________ creates trans fats, a type of unsaturated fat in which some of the double bonds are less kinked than those in naturally occurring unsaturated fats. (65)

Back 840

In some cases, unsaturated fats in food products may be artificially [HYDROGENATED] (industrial addition of hydrogens) to make them more saturated, extending the shelf life of these products. In some cases, the [HYDROGENATION] creates trans fats, a type of unsaturated fat in which some of the double bonds are less kinked than those in naturally occurring unsaturated fats. (65)

Front 841

Eating _____ fats and _________ fats may increase the risk of heart disease. (65)

Back 841

Eating [TRANS] fats and [SATURATED] fats may increase the risk of heart disease. (65)

Front 842

Organisms also contain other types of ______ that play many roles in cells in addition to ______ storage. (65)

Back 842

Organisms also contain other types of [LIPIDS] that play many roles in cells in addition to [ENERGY] storage. (65)

Front 843

The male and female sex hormones testosterone and estradiol are ______ called ________. (65)

Back 843

The male and female sex hormones testosterone and estradiol are [LIPIDS] called [STEROIDS]. (65)

Front 844

Unlike the structure of fats shown in figure 3.15, the structure of steroids consists of multiple ____ structures and looks somewhat like a section of chicken wire. (65)

Back 844

Unlike the structure of fats shown in figure 3.15, the structure of steroids consists of multiple [RING] structures and looks somewhat like a section of chicken wire. (65)

Front 845

Other important biological lipids include _____________, ___________ (also a steroid), ______, _____, and ________, such as the chlorophyll that makes plants green and the retinal that your eyes use to detect light (see figure 3.16). (65)

Back 845

Other important biological lipids include [PHOSPHOLIPIDS], [CHOLESTEROL] (also a steroid), [RUBBER], [WAXES], and [PIGMENTS], such as the chlorophyll that makes plants green and the retinal that your eyes use to detect light (see figure 3.16). (65)

Front 846

Figure 3.15 – Saturated and unsaturated fats. (a) Fat molecules each contain a three-carbon glycerol to which is attached three fatty acid tails. (b) Most ______ fats are “saturated” (every carbon atom carries the maximum load of hydrogens). Their fatty acid chains fit closely together, and these triacylglycerols form immobile arrays called hard fats. (c) Most _____ fats are unsaturated, which prevents close association between triacylglycerols and produces oils. (65)

Back 846

Figure 3.15 – Saturated and unsaturated fats. (a) Fat molecules each contain a three-carbon glycerol to which is attached three fatty acid tails. (b) Most [ANIMAL] fats are “saturated” (every carbon atom carries the maximum load of hydrogens). Their fatty acid chains fit closely together, and these triacylglycerols form immobile arrays called hard fats. (c) Most [PLANT] fats are unsaturated, which prevents close association between triacylglycerols and produces oils. (65)

Front 847

If you look at figure 3.17, you will see two types of lipids that play key roles in the membranes that encase the cells of your body: ____________ molecules and ___________. (67)

Back 847

If you look at figure 3.17, you will see two types of lipids that play key roles in the membranes that encase the cells of your body: [PHOSPHOLIPID] molecules and [CHOLESTEROL]. (67)

Front 848

_____________ are modified triacylglycerol molecules in which one of the carbons in the glycerol backbone bonds to a phosphate group rather than to a third fatty acid (compare figure 3.15a and 3.16a). This gives the molecule an overall shape of a polar ____ and two nonpolar _____. (67)

Back 848

[PHOSPHOLIPIDS] are modified triacylglycerol molecules in which one of the carbons in the glycerol backbone bonds to a phosphate group rather than to a third fatty acid (compare figure 3.15a and 3.16a). This gives the molecule an overall shape of a polar [HEAD] and two nonpolar [TAILS]. (67)

Front 849

In water, the ________ ends of the phospholipids group together through hydrophobic interactions, leaving the _____ heads to interact with water molecules. These interactions result in the formation of two layers of molecules with the ________ tails pointed inside – a lipid bilayer. All biological membranes, those that surround the cell and those found inside the cell, have this arrangement. (67)

Back 849

In water, the [NONPOLAR] ends of the phospholipids group together through hydrophobic interactions, leaving the [POLAR] heads to interact with water molecules. These interactions result in the formation of two layers of molecules with the [NONPOLAR] tails pointed inside – a lipid bilayer. All biological membranes, those that surround the cell and those found inside the cell, have this arrangement. (67)

Front 850

Most animal cell membranes also contain the steroid ___________, a lipid composed of four carbon rings (see figure 3.16b). (67)

Back 850

Most animal cell membranes also contain the steroid [CHOLESTEROL], a lipid composed of four carbon rings (see figure 3.16b). (67)

Front 851

Cholesterol helps membranes stay ________. However, excess saturated fat intake can cause plugs of cholesterol to form in the _____ _______, which may lead to blockage, high blood pressure, stroke, or heart attack. (67)

Back 851

Cholesterol helps membranes stay [FLEXIBLE]. However, excess saturated fat intake can cause plugs of cholesterol to form in the [BLOOD VESSELS], which may lead to blockage, high blood pressure, stroke, or heart attack. (67)

Front 852

Key Learning Outcome 3.5 – Lipids are not _____-_______. (67)

Back 852

Key Learning Outcome 3.5 – Lipids are not [WATER-SOLUBLE]. (67)

Front 853

Fats contain chains of fatty acid ________ that store energy. (67)

Back 853

Fats contain chains of fatty acid [SUBUNITS] that store energy. (67)

Front 854

Other lipids include _____________, ________, and ______. (67)

Back 854

Other lipids include [PHOSPHOLIPIDS], [STEROIDS], and [RUBBER]. (67)

Front 855

Figure 3.16 – Types of lipid molecules. (a) A ____________ is similar to a fat molecule with the exception that one of the fatty acid tails is replaced with a polar group linked to the glycerol by a phosphate group. (67)

Back 855

Figure 3.16 – Types of lipid molecules. (a) A [PHOSPHOLIPID] is similar to a fat molecule with the exception that one of the fatty acid tails is replaced with a polar group linked to the glycerol by a phosphate group. (67)

Front 856

Figure 3.16 – Types of lipid molecules. (b) ________ like cholesterol are lipids with complex ring structures. (67)

Back 856

Figure 3.16 – Types of lipid molecules. (b) [STEROIDS] like cholesterol are lipids with complex ring structures. (67)

Front 857

Figure 3.16 – Types of lipid molecules. (c) _______ ______ is a linear polymer of a five-carbon unit called isoprene (two isoprene units are shown here; one unit has its carbon in green and the other in red). ______, made from latex harvested from rubber trees, is used in many products such as car tires.

Back 857

Figure 3.16 – Types of lipid molecules. (c) [NATURAL RUBBER] is a linear polymer of a five-carbon unit called isoprene (two isoprene units are shown here; one unit has its carbon in green and the other in red). [RUBBER], made from latex harvested from rubber trees, is used in many products such as car tires.

Front 858

Figure 3.16 – Types of lipid molecules. (d) ___________ a has a multiringed area and a long hydrocarbon tail. Chlorophyll is the primary pigment used in photosynthesis, and it is what makes leaves green. (67)

Back 858

Figure 3.16 – Types of lipid molecules. (d) [CHLOROPHYLL] a has a multiringed area and a long hydrocarbon tail. Chlorophyll is the primary pigment used in photosynthesis, and it is what makes leaves green. (67)

Front 859

Figure 3.17 – Lipids are a key component of biological _________. (67)

Back 859

Figure 3.17 – Lipids are a key component of biological [MEMBRANES]. (67)

Front 860

Lipids are one of the most ______ molecules in the human body, because the membranes of all the body’s 10 trillion cells are composed largely of lipids called _____________. (67)

Back 860

Lipids are one of the most [COMMON] molecules in the human body, because the membranes of all the body’s 10 trillion cells are composed largely of lipids called [PHOSPHOLIPIDS]. (67)

Front 861

Membranes also contain ___________, another type of lipid. (67)

Back 861

Membranes also contain [CHOLESTEROL], another type of lipid. (67)

Front 862

3.1.1 Living organisms produce organic macromolecules, which are large ______-based molecules. The chemical properties of these molecules are due to unique functional groups that are attached to the ______ core. (69)

Back 862

3.1.1 Living organisms produce organic macromolecules, which are large [CARBON]-based molecules. The chemical properties of these molecules are due to unique functional groups that are attached to the [CARBON] core. (69)

Front 863

3.1.2a Large molecules called ______________ are formed by dehydration reactions (figure 3.3a), in which molecular subunits called ________ are linked together through covalent bonding. The reaction is called a dehydration reaction because a water molecule is a _______ of the reaction. (69)

Back 863

3.1.2a Large molecules called [MACROMOLECULES] are formed by dehydration reactions (figure 3.3a), in which molecular subunits called [MONOMERS] are linked together through covalent bonding. The reaction is called a dehydration reaction because a water molecule is a [PRODUCT] of the reaction. (69)

Front 864

3.1.2b The breakdown of a macromolecule involves a __________ reaction, where a water molecule is broken down into H+ and OH-. These ____ disrupt the covalent bond that holds two monomers together, causing the bond to break. (69)

Back 864

3.1.2b The breakdown of a macromolecule involves a [HYDROLYSIS] reaction, where a water molecule is broken down into H+ and OH-. These [IONS] disrupt the covalent bond that holds two monomers together, causing the bond to break. (69)

Front 865

3.1.2c _____ _____ are the subunits that link together to form polypeptides. (69)

Back 865

3.1.2c [AMINO ACIDS] are the subunits that link together to form polypeptides. (69)

Front 866

__________ ________ link together to form nucleic acids. (69)

Back 866

[NUCLEOTIDE MONOMERS] link together to form nucleic acids. (69)

Front 867

______________ ________ link together to form carbohydrates. (69)

Back 867

[MONOSACCHARIDE MONOMERS] link together to form carbohydrates. (69)

Front 868

_____ _____ are the monomers that link together to form a type of lipid called fats. (69)

Back 868

[FATTY ACIDS] are the monomers that link together to form a type of lipid called fats. (69)

Front 869

3.2.1a ________ are macromolecules that carry out many functions in the cell. They are produced by the linking together of _____ ____ subunits that form a chain called a polypeptide. (69)

Back 869

3.2.1a [PROTEINS] are macromolecules that carry out many functions in the cell. They are produced by the linking together of [AMINO ACID] subunits that form a chain called a polypeptide. (69)

Front 870

3.2.1b There are 20 different _____ _____ found in proteins. (69)

Back 870

3.2.1b There are 20 different [AMINO ACIDS] found in proteins. (69)

Front 871

All amino acids have the same basic core _________. They differ in the type of __________ _____ attached to the core. (69)

Back 871

All amino acids have the same basic core [STRUCTURE]. They differ in the type of [FUNCTIONAL GROUP] attached to the core. (69)

Front 872

The functional groups are referred to as _ ______ and give the amino acid ______ chemical properties. (69)

Back 872

The functional groups are referred to as [R GROUPS] and give the amino acid [UNIQUE] chemical properties. (69)

Front 873

3.2.2 Amino acids are linked together with covalent bonds referred to as _______ _____. (69)

Back 873

3.2.2 Amino acids are linked together with covalent bonds referred to as [PEPTIDE BONDS]. (69)

Front 874

3.2.3 The sequence of amino acids within the polypeptide is the _______ structure of the protein. (69)

Back 874

3.2.3 The sequence of amino acids within the polypeptide is the [PRIMARY] structure of the protein. (69)

Front 875

The chain of amino acids can twist into a _________ structure, where hydrogen bonding holds portions of the polypeptide in a ______ shape, called an α-helix, or in ______ called β-pleated ______. (69)

Back 875

The chain of amino acids can twist into a [SECONDARY] structure, where hydrogen bonding holds portions of the polypeptide in a [COILED] shape, called an α-helix, or in [SHEETS] called β-pleated [SHEETS]. (69)

Front 876

Further bending and folding of the polypeptide results in its ________ structure. (69)

Back 876

Further bending and folding of the polypeptide results in its [TERTIARY] structure. (69)

Front 877

When two or more polypeptides are present in a protein, the interaction of these polypeptide subunits is its __________ structure. (69)

Back 877

When two or more polypeptides are present in a protein, the interaction of these polypeptide subunits is its [QUATERNARY] structure. (69)

Front 878

3.2.4 Changes in environmental conditions that disrupt ________ bonding can cause a protein to unfold, a process called ____________. (69)

Back 878

3.2.4 Changes in environmental conditions that disrupt [HYDROGEN] bonding can cause a protein to unfold, a process called [DENATURATION]. (69)

Front 879

3.2.5 ________ proteins (page 57) cannot function if they are denatured. The _________ of the protein determines its function. (69)

Back 879

3.2.5 [GLOBULAR] proteins (page 57) cannot function if they are denatured. The [STRUCTURE] of the protein determines its function. (69)

Front 880

3.2.6 _________ proteins aid in the folding of the amino acid chain into the correct _____. (69)

Back 880

3.2.6 [CHAPERONE] proteins aid in the folding of the amino acid chain into the correct [SHAPE]. (69)

Front 881

3.2.7 Some diseases may be caused by misfolded, and therefore _____________, proteins. (69)

Back 881

3.2.7 Some diseases may be caused by misfolded, and therefore [NONFUNCTIONAL], proteins. (69)

Front 882

3.3.1 Nucleic acids, such as DNA and RNA, are long chains of nucleotides. Nucleotides contain three parts: a ____-______ _____, a _________ _____, and a ___________ ____. (69)

Back 882

3.3.1 Nucleic acids, such as DNA and RNA, are long chains of nucleotides. Nucleotides contain three parts: a [FIVE-CARBON SUGAR], a [PHOSPHATE GROUP], and a [NITROGENOUS BASE]. (69)

Front 883

DNA and RNA function as information storage molecules in the cell, storing the information needed to build ________. The information is stored as different _________ of nucleotides. (69)

Back 883

DNA and RNA function as information storage molecules in the cell, storing the information needed to build [PROTEINS]. The information is stored as different [SEQUENCES] of nucleotides. (69)

Front 884

3.3.2a DNA and RNA differ chemically in that the sugar found in DNA is ___________ and in RNA is ______. (69)

Back 884

3.3.2a DNA and RNA differ chemically in that the sugar found in DNA is [DEOXYRIBOSE] and in RNA is [RIBOSE]. (69)

Front 885

The nitrogenous bases in DNA are ________, _______, _______, and _______, and the same are found in RNA except for _______, which is substituted with ______. (69)

Back 885

The nitrogenous bases in DNA are [CYTOSINE], [ADENINE], [GUANINE], and [THYMINE], and the same are found in RNA except for [THYMINE], which is substituted with [URACIL]. (69)

Front 886

3.3.2b DNA and RNA also differ ____________. DNA contains two strands of nucleotides wound around each other, called a ______ _____. RNA, as shown in figure 3.10, is a ______ strand of nucleotides. (69)

Back 886

3.3.2b DNA and RNA also differ [STRUCTURALLY]. DNA contains two strands of nucleotides wound around each other, called a [DOUBLE HELIX]. RNA, as shown in figure 3.10, is a [SINGLE] strand of nucleotides. (69)

Front 887

3.3.3 The two nucleotide strands of the DNA double helix are held together through highly directional ________ bonding between ___________ bases: adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). (69)

Back 887

3.3.3 The two nucleotide strands of the DNA double helix are held together through highly directional [HYDROGEN] bonding between [NITROGENOUS] bases: adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). (69)

Front 888

3.4.1a Carbohydrates, also referred to as sugars, are macromolecules that serve two primary functions in the cell: __________ framework and ______ storage. (69)

Back 888

3.4.1a Carbohydrates, also referred to as sugars, are macromolecules that serve two primary functions in the cell: [STRUCTURAL] framework and [ENERGY] storage. (69)

Front 889

3.4.1b Carbohydrates that consist of only one or two monomers are called ______ ______ (figure 3.12). Carbohydrates that consist of long chains of monomers are called _______ _____________ or polysaccharides. (69)

Back 889

3.4.1b Carbohydrates that consist of only one or two monomers are called [SIMPLE SUGARS] (figure 3.12). Carbohydrates that consist of long chains of monomers are called [COMPLEX CARBOHYDRATES] or polysaccharides. (69)

Front 890

3.4.2 Polysaccharides such as starch and glycogen provide a means of _______ ______ in the cell. Carbohydrates such as cellulose and chitin cannot be digested by most organisms, and serve to provide __________ _________. (69)

Back 890

3.4.2 Polysaccharides such as starch and glycogen provide a means of [STORING ENERGY] in the cell. Carbohydrates such as cellulose and chitin cannot be digested by most organisms, and serve to provide [STRUCTURAL INTEGRITY]. (69)

Front 891

3.5.1 ______ are large nonpolar molecules that are insoluble in water. (69)

Back 891

3.5.1 [LIPIDS] are large nonpolar molecules that are insoluble in water. (69)

Front 892

Fats that function in ____-term ______ storage include saturated fats (figure 3.15) and unsaturated fats. (69)

Back 892

Fats that function in [LONG]-term [ENERGY] storage include saturated fats (figure 3.15) and unsaturated fats. (69)

Front 893

_________ fats are solid at room temperature and are found in _______, while ___________ fats are liquid (oils) at room temperature and found in ______. (69)

Back 893

[SATURATED] fats are solid at room temperature and are found in [ANIMALS], while [UNSATURATED] fats are liquid (oils) at room temperature and found in [PLANTS]. (69)

Front 894

3.5.2 Other ______ include the steroids (including the sex steroids and cholesterol), rubber, and pigments such as chlorophyll. All have very different __________ and very different _________. (69)

Back 894

3.5.2 Other [LIPIDS] include the steroids (including the sex steroids and cholesterol), rubber, and pigments such as chlorophyll. All have very different [STRUCTURES] and very different [FUNCTIONS]. (69)

Front 895

All cells are encased in a ______ ________, called the lipid bilayer, that is composed of ___ layers of modified fat molecules called phospholipids, which are quite _____. (69)

Back 895

All cells are encased in a [PLASMA MEMBRANE], called the lipid bilayer, that is composed of [TWO] layers of modified fat molecules called phospholipids, which are quite [POLAR]. (69)

Front 896

3.1.1 The four kinds of organic macromolecules are: (70)
a. Hydroxyls, carboxyls, aminos, and phosphates.
b. Proteins, carbohydrates, lipids, and nucleic acids.
c. DNA, RNA, simple sugars, and amino acids.
d. Carbon, hydrogen, oxygen, and nitrogen.

Back 896

3.1.1 The four kinds of organic macromolecules are: (70)
b. Proteins, carbohydrates, lipids, and nucleic acids.

Front 897

3.1.2 Organic molecules are made up of monomers. Which of the following are NOT considered monomers of organic molecules? (70)
a. Amino acids
b. Monosaccharides
c. Polypeptides
d. Nucleotides

Back 897

3.1.2 Organic molecules are made up of monomers. Which of the following are NOT considered monomers of organic molecules? (70)

c.Polypeptides

Front 898

3.2.1a Your body is filled with many types of proteins. Each type has a distinctive sequence of amino acids that determines both its specialized _______ and its specialized _______. (70)
a. Number, weight
b. Length, mass
c. Structure, function
d. Charge, pH

Back 898

3.2.1a Your body is filled with many types of proteins. Each type has a distinctive sequence of amino acids that determines both its specialized _______ and its specialized _______. (70)
c. Structure, function

Front 899

3.2.1b A peptide bond forms: (70)
a. By the removal of a water molecule.
b. By a dehydration reaction.
c. Between two amino acids.
d. All of the above.

Back 899

3.2.1b A peptide bond forms: (70)
d. All of the above.

Front 900

3.2.2a In dehydration synthesis, water: (70)
a. Is removed from a protein.
b. Is added to a protein.
c. Is added to amino acids.
d. Is removed from amino acids.

Back 900

3.2.2a In dehydration synthesis, water: (70)
d. Is removed from amino acids.

Front 901

3.2.2b How many molecules of water are used up in the breakdown of a polypeptide that is 14 amino acids in length? (70)

Back 901

How many molecules of water are used up in the breakdown of a polypeptide that is 14 amino acids in length? (70)

The breakdown of this polypeptide takes 13 molecules of water: one for each of the 13 peptide bonds that links the 14 amino acids in the polypeptide chain.

Front 902

3.2.3a The four general levels of protein structure do NOT include _______ structure. (70)
a. Primary
b. Tertiary
c. Quaternary
d. Binary

Back 902

3.2.3a The four general levels of protein structure do NOT include _______ structure. (70)
d. Binary

Front 903

3.2.3b Which of the following amino acids would be expected to occur in the interior of a globular protein? (70)
a. Asparagine
b. Phenylalanine
c. Aspartic acid
d. A polar amino acid

Back 903

3.2.3b Which of the following amino acids would be expected to occur in the interior of a globular protein? (70)
b. Phenylalanine

Front 904

3.2.4a The denaturation of a protein is typically the result of: (70)
a. Catalysis.
b. Cooling.
c. Heating.
d. Buffering.

Back 904

3.2.4a The denaturation of a protein is typically the result of: (70)
c. Heating.

Front 905

3.2.4b A single-subunit protein that is denatured by heat loses its: (70)
a. Primary structure
b. Secondary structure
c. Amino acid structure
d. Quaternary structure

Back 905

3.2.4b A single-subunit protein that is denatured by heat loses its: (70)
b. Secondary structure

Front 906

3.2.5a Which of the following in NOT a function of structural proteins? (70)
a. Catalysis
b. Muscle contraction
c. Shape determination
d. Structural strength

Back 906

3.2.5a Which of the following in NOT a function of structural proteins? (70)
a. Catalysis

Front 907

3.2.5b Catalysis is: (70)
a. Restoring secondary structure.
b. Denaturation in reverse.
c. Protein enlargement.
d. Enhancing chemical reactions.

Back 907

3.2.5b Catalysis is: (70)
d. Enhancing chemical reactions.

Front 908

3.2.6 If a protein’s primary structure dictates its tertiary structure and thus its function, why would it need a chaperone protein to fold correctly? (70)

Back 908

If a protein’s primary structure dictates its tertiary structure and thus its function, why would it need a chaperone protein to fold correctly? (70)

Proteins can fold in so many different ways due to hydrophobic interactions that trial and error folding would take too long. Also, hydrophobic portions of proteins exposed during folding would stick to hydrophobic portions of other proteins and form gluey clumps. Chaperone proteins assist proteins in folding correctly and isolate proteins during folding to prevent aggregation.

Front 909

3.2.7 A prion is a(n): (70)
a. Animal virus.
b. Misfolded protein.
c. Naked DNA molecule.
d. Plasmid.

Back 909

3.2.7 A prion is a(n): (70)
b. Misfolded protein.

Front 910

3.3.1a Nucleic acids: (70)
a. Are the energy source for our bodies.
b. Act on other molecules, breaking them apart.
c. Are found only in a few, specialized locations in the body.
d. Are information storage devices found in body cells.

Back 910

3.3.1a Nucleic acids: (70)
d. Are information storage devices found in body cells.

Front 911

3.3.1b A nucleotide is composed of all of the following except: (70)
a. 5-carbon sugar.
b. Nitrogen base.
c. 6-carbon sugar.
d. Phosphate group.

Back 911

3.3.1b A nucleotide is composed of all of the following except: (70)
c. 6-carbon sugar.

Front 912

3.3.2a Which carbohydrate is part of a molecule of RNA? (70)
a. Galactose
b. Deoxyribose
c. Ribose
d. Glucose

Back 912

3.3.2a Which carbohydrate is part of a molecule of RNA? (70)
c. Ribose

Front 913

3.3.2b DNA exists in cells as a double-stranded duplex molecule, whereas RNA, which is composed of very similar nucleotides linked together in the same way, does not form a double-stranded duplex in cells. Why not? If you were to place complementary single-strands of RNA in a test tube, would they spontaneously form duplex molecules? (70)

Back 913

DNA exists in cells as a double-stranded duplex molecule, whereas RNA, which is composed of very similar nucleotides linked together in the same way, does not form a double-stranded duplex in cells. Why not? If you were to place complementary single-strands of RNA in a test tube, would they spontaneously form duplex molecules? (70)

RNA can and does form short duplexes of complementary strands, and some of these segments play regulatory roles in the cell, such as gene silencing and transcription termination. DNA, on the other hand, has evolved to archive the genetic information of the cell, and the enzyme DNA polymerase catalyzes the synthesis of double-stranded DNA, which helps with proofreading and preventing errors. Thus, there is really nothing to prevent RNA from forming a duplex, but no enzyme has evolved to catalyze the synthesis of RNA duplexes.

Front 914

3.3.3a The two strands of DNA molecule are held together through hydrogen bonds between nucleotide bases. Which of the following best describes this base pairing in DNA? (70)
a. Adenine forms hydrogen bonds with thymine.
b. Adenine forms hydrogen bonds with cytosine.
c. Cytosine forms hydrogen bonds with thymine.
d. Guanine forms hydrogen bonds with adenine.

Back 914

3.3.3a The two strands of DNA molecule are held together through hydrogen bonds between nucleotide bases. Which of the following best describes this base pairing in DNA? (70)
a. Adenine forms hydrogen bonds with thymine.

Front 915

3.3.3b If the sequence of one chain of DNA double helix is TAACGTA, the sequence of its partner strand in the double helix must be: (70)
a. TAACGTA.
b. ATGCAAT.
c. ATTGCAT.
d. TACGTTA.

Back 915

3.3.3b If the sequence of one chain of DNA double helix is TAACGTA, the sequence of its partner strand in the double helix must be: (70)
c. ATTGCAT.

Front 916

3.4.1a Carbohydrates are used for: (70)
a. Structure and energy.
b. Information storage.
c. Fat storage and hair.
d. Hormones and enzymes.

Back 916

3.4.1a Carbohydrates are used for: (70)
a. Structure and energy.

Front 917

3.4.1b A carbohydrate is any molecule that contains carbon, hydrogen, and oxygen in the ratio _____. (70)
a. 2:1:2
b. 1:1:1
c. 1:2:1
d. 1:2:2

Back 917

3.4.1b A carbohydrate is any molecule that contains carbon, hydrogen, and oxygen in the ratio _____. (70)
c. 1:2:1

Front 918

3.4.2a Which of the following carbohydrates is NOT found in plants? (70)
a. Glycogen
b. Cellulose
c. Starch
d. All are found in plants.

Back 918

3.4.2a Which of the following carbohydrates is NOT found in plants? (70)
a. Glycogen

Front 919

3.4.2b The amylase enzyme present in the cells of your body can break the bonds between the glucose monomers in starch, but it cannot break the bonds between the glucose monomers in cellulose. Explain why the same enzyme that breaks down starch cannot break down cellulose. (70)

Back 919

The amylase enzyme present in the cells of your body can break the bonds between the glucose monomers in starch, but it cannot break the bonds between the glucose monomers in cellulose. Explain why the same enzyme that breaks down starch cannot break down cellulose. (70)

The glucose subunits in cellulose are joined in alternating orientations, creating long, unbranched chains. The glucose monomers of starch, however, are all joined trhe same way. Thus, an enzyme that is able to break the bonds of starch would not be able to break the bonds of cellulose because the enzyme would not recognize the different linkages in cellulose.

Front 920

3.5.1a A characteristic common to fat molecules is that they: (70)
a. Contain long chains of C-H bonds.
b. Are insoluble in water.
c. Have a glycerol backbone.
d. All of these are characteristics of fats.

Back 920

3.5.1a A characteristic common to fat molecules is that they: (70)
d. All of these are characteristics of fats.

Front 921

3.5.1b A saturated animal fat differs from an unsaturated fat in that it: (70)
a. Is solid at room temperature.
b. Is insoluble in water.
c. Contains three fatty acids.
d. Contains double bonds in its fatty acid chains.

Back 921

3.5.1b A saturated animal fat differs from an unsaturated fat in that it: (70)
a. Is solid at room temperature.

Front 922

3.5.2a Lipids are used for: (70)
a. Motion and defense.
b. Information storage.
c. Energy storage and for some hormones.
d. Enzymes and for some hormones.

Back 922

3.5.2a Lipids are used for: (70)
c. Energy storage and for some hormones.

Front 923

3.5.2b Unlike a phospholipid, cholesterol has: (70)
a. A glycerol backbone.
b. A polar phosphate group.
c. A multiple ring structure.
d. Unsaturated fatty acid chains.

Back 923

3.5.2b Unlike a phospholipid, cholesterol has: (70)
c. A multiple ring structure.