251 Test #1

Front 1

When did Earth form?

Back 1

Between 4.6 and 4.5 billion years ago

Front 2

When did the earliest life evolve on earth?

Back 2

about 600 million years after Earth formed

Front 3

What was the critical step in the evolution of life?

Back 3

Formation of nucleic acids that could reproduce themselves and contain information to produce proteins

Front 4

What were the next steps after the critical step?

Back 4

Formation of cells

- Enclosed in membranes: Fatty acids important in membrane production

Front 5

what were all living organisms at first and for how long?

Back 5

Unicellular prokaryotes for 2 billion years

Front 6

Where did all of the first organisms live?

Back 6

In the deep ocean

Front 7

When did photosynthesis evolve?

Back 7

2.7 billion years ago

cyanobacteria

Front 8

Why was photosynthesis important?

Back 8

Oxygen was a byproduct of photosynthesis so it began to accumulate in the atmosphere. organisms could now move to land. Organisms that could tolerate O2 also evolved aerobic metabolism so organisms were able to grow larger

Front 9

What is endosymbiosis? What are the two examples?

Back 9

Larger cell engulfs smaller. Led to some organelles. Mitochondria (bacteria) and chloroplasts (cyanobacteria)

Front 10

When and how did multicellular organisms evolve?

Back 10

Multicellular organisms arose about 1 billion years ago. Groups of eukaryote cells probably failed to separate after division.

Front 11

What is cellular specialization and why was it important?

Back 11

cells become specialized to perform certain functions. organisms larger and could adapt to certain environments.

Front 12

What are mutations? What level do they occur at?

Back 12

introduced when a genome is replicated. create variability that affects survival. At the individual level

Front 13

What are the three domains of life?

Back 13

Bacteria (prokary) , Archea (prokary), Eukarya

Front 14

What is a system?

Back 14

is a set of interacting parts(components) in which neither the parts nor the whole can be understood without taking into account the interactions (processes).

Front 15

What does biological systems are dynamic mean?

Back 15

Characterized by rapid flows of matter and energy.

They constantly exchange energy and matter with their surroundings.

Front 16

What are positive and negative feedbacks?

Back 16

Positive feedback occurs when a product of the system speeds up an earlier process.

Negative feedback occurs when a product of the system slows down an earlier process.

Front 17

What do positive and negative feedbacks tend to do?

Back 17

Positive feedback tends to destabilize a system(sometimes advantageous, provided it is ultimately brought under control).

Negative feedback tends to stabilize systems and is very common in regulatory systems.

Front 18

What is a genome?

Back 18

is the sum total of all theinformation encoded by an organism’s genes.

Front 19

What does DNA consist of?

Back 19

consists of repeating subunits callednucleotides.

Front 20

What is a gene?

Back 20

a specific segment of DNA thatcontains information for making one or more

Front 21

What is the The central dogma of molecular biology

Back 21

"DNA makes RNA andRNA makes protein.”

Front 22

What is a major focus of biological research (about DNA)

Back 22

All cells in a multicellular organism contain the same genome, but different cells have different functions.The different types of cells must express different parts of the genome.How cells control genomeexpression is a major focus of biological research.

Front 23

What is Evolution? What level does it occur at?

Back 23

is a change in genetic makeup ofbiological populations through time—a major unifying principle of biology. Population level.

Front 24

What did Charles Darwin propose? and what does it mean?

Back 24

all living organisms are descended from a common ancestor by the mechanismof natural selection.

Front 25

What is a theory?

Back 25

is a body of scientific workin which rigorously tested and well-establishedfacts and principles are used to make predictions about the natural world.

Front 26

What elements make up most living things?

Back 26

HOPSCN

Front 27

What type of bond is strongest?

Back 27

Covalent

Front 28

What is electronegativity?

Back 28

the attractiveforce that an atomic nucleus exerts on electrons.

Front 29

Why do polar molecules dissolve in water? What are these molecules called?

Back 29

They form hydrogen bonds with the water molecules. Hydrophillic

Front 30

Why does water have high heat capacity and why is this important to organisms?

Back 30

form multiple hydrogenbonds with each other

protects organisms from fluctuating environmental temperature

Front 31

What does hydrophilic mean?

Back 31

in aqueoussolutions, polar molecules become separated and surrounded by water molecules.

Front 32

What does hydrophobic mean?

Back 32

Molecules with nonpolar covalent bonds show greater attraction to one another than to water (they are hydrophobic)

Front 33

Why do ionic molecules dissolve in water?

Back 33

Because ionic bonds are weak the polar ends of the water molecule pull apart the ions

Front 34

What are functional groups?

Back 34

small groups of atomswith specific chemical properties

Front 35

What is a hydroxyl?

Back 35

OH

Front 36

What is Aldehyde?

Back 36

H-C=O

Front 37

What is Keto?

Back 37

C=O

Front 38

What is Carboxyl?

Back 38

O=C-OH

Front 39

What is amino?

Back 39

H-N-H

Front 40

What proportion of living tissue is water?

Back 40

About 70%

Front 41

What are the 4 macromolecules in order of highest % to Lowest %?

Back 41

Proteins, Nucleic Acids, Carbohydrates, and Lipids

Front 42

What are proteins?

Back 42

Proteins—formed from differentcombinations of 20 amino acids

Front 43

What are Carbohydrates?

Back 43

Carbohydrates—formed by linkingsugar monomers (monosaccharides) to form polysaccharides

Front 44

What are Nucleic Acids?

Back 44

Nucleic acids—formed from four kindsof nucleotide monomers

Front 45

What are Lipids?

Back 45

Nucleic acids—formed from four kindsof nucleotide monomers

Front 46

What is Condensation and what does it do?

Back 46

Condensation—removal of water linksmonomers together

Front 47

What is Hydrolysis and what does it do?

Back 47

Hydrolysis—addition of water breaks apolymer into monomers

Front 48

What do Carbohydrates do?

Back 48

Source of stored energy

Transport stored energy within organisms

Structural molecules give many organisms their shapes

Recognition or signaling molecules can trigger specific biological responses

Front 49

What are monosaccharides?

Back 49

simple sugers

Front 50

What is pentose? What are examples?

Back 50

Pentoses are 5-carbon simple sugars.

Ribose and deoxyribose are thebackbones of RNA and DNA.

Front 51

What are Hexoses? What are examples?

Back 51

simple sugars (C6H12O6) includeglucose, fructose, mannose, and galactose. They are importantstructural and energy sugars.

Front 52

What are disaccharides? What is an example?

Back 52

Covalently bonded monosaccharides by condensation Example Sucrose

Front 53

What are Polysaccharides? and the 3 examples?

Back 53

are large polymers ofmonosaccharides connected byglycosidic linkages

Starch,Glycogen, and Cellulose

Front 54

What is starch?

Back 54

Starches—polymers of glucose,storage in plants

Front 55

What is Glycogen?

Back 55

Glycogen—highly branched polymer ofglucose; main energy storage molecule in mammals

Front 56

What is Cellulose?

Back 56

It is the most abundant carbon- containing (organic) biological compound on Earth.

Main component of cell walls

Very stable and good for structure

Front 57

What is the difference between fats & oils?

Back 57

Fat is solid @ room temperature and Oil is a liquid

Front 58

What are lipids?

Back 58

Hydrocarbons (composed of C and H atoms) thatare insoluble in water because of many nonpolar covalent bonds. Hydrophobic

Front 59

What are triglycerides?

Back 59

3 fatty acids & 1 glycerol

Front 60

what are ester linkages?

Back 60

Synthesis of a triglyceride involves threecondensation reactions forming ester linkages

Front 61

What are saturated fatty acids?

Back 61

all bonds betweencarbon atoms are single; they are saturated with hydrogens.

Front 62

Difference between fats from plants and animals

Back 62

Animals: solid = saturated

Plants: liquid= unsaturated

Front 63

What is amphipathic? and what has this characteristic?

Back 63

fatty acids; they have ahydrophilic end and a hydrophobic tail.

Front 64

Which stores more energy lipids or carbohydrates?

Back 64

Lipids (twice as much)

Front 65

What is free energy?

Back 65

is energy that cando work when temperature and pressure are uniform

Front 66

What is deltaG?

Back 66

Portion of a system’s energy that can perform work is measured by = Gibbs free energy

Front 67

is gibbs free energy positive or negative for spontaneous processes?

Back 67

negative

Front 68

Describe spontaneous (Exergonic reactions)

Back 68

More free Energy (lower energy state) in Reactants than products energy is released

Front 69

What is metabolism?

Back 69

sum total of all chemical reactions occuring in biological system at a given time

Front 70

What are Anabolic reactions?

Back 70

Consume energy to build complex molecules from simpler ones. positive gibbs free energy/endergonic

Front 71

What are catabolic reactions?

Back 71

Release energy by breakingdown complex molecules into simpler compounds. gibbs free energy negative exergonic

Front 72

What is energy coupling and what is the major example?

Back 72

the use of an exergonicprocess to drive an endergonic one

In the cell, the energy from the exergonic reaction of ATP hydrolysis can be used to drive an endergonic reaction

Front 73

What are the bases of RNA

Back 73

Adenine, cytosine, guanine, and Uracil

Front 74

What are the bases of DNA

Back 74

Adenine,cytosine,guanine, and thymine

Front 75

What are the complementary bases

Back 75

A-T, C-G for rna A-U, C-G

Front 76

What are nucleic acids?

Back 76

polymers that store, transmit, and express hereditary (genetic info)

Front 77

What are the two functions of DNA?

Back 77

Replication

Information is copied to RNA and used to specify amino acid sequences in proteins.

Front 78

What are genes?

Back 78

Genes—DNA sequences that encode specificproteins and are transcribed into RNA

Front 79

What is gene expression and what does it cause?

Back 79

transcription and translation ofa specific gene.

All cells contain an entire genome but due to different expression individual cells carry out specific tasks or exhibit different structures.

Front 80

What is the primary structure of a protein?

Back 80

of a protein is the sequenceof amino acids.

Front 81

What is the secondary structure of a protein?

Back 81

structure—regular, repeated spatialpatterns in different regions, resulting from hydrogen bonding

Front 82

What do enzymes do?

Back 82

Lower the activation energy

Front 83

What are substrates?

Back 83

the reactants, they bind to specific sites of the enzyme (active site)

Front 84

What are cofactors?

Back 84

Some enzymes require ions or other molecules(cofactors) in order to function

Front 85

What are metabolic pathways?

Back 85

The product of one reaction is the substrate for the next reaction

Front 86

Catabolic and Anabolic reactions: exergonic or endergonic

Back 86

Cat: Exergonic

An: Endergonic

Front 87

How do cells regulate metabolic pathways?

Back 87

by controlling the amount of an enzyme available

Front 88

What are chemical inhibitors?

Back 88

they bind to enzymes to slow down reaction rates