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174 Cards in this Set
- Front
- Back
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Scientists use __ main approaches to learn about nature
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Discovery science and Hypothesis based science |
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Hypothesis- based science
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uses observations/ data from discovery science to stimulate us to seek natural causes and explanation
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Hypothesis
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is a proposed explanation for a set of observations
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A good hypothesis leads to?
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predictions that scientists can test by recording more observations or designing experiments
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Deductive reasoning
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the logic used in hypothesis based science to come up with ways to test the hypothesis
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Theory
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a well founded generalization supported by large number of observation and experiments.
Theories continue to generate new hypothesis that can be tested. |
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Hypothesis must be?
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Testable and falsifiable
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Experimental group
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Add variables that will prove or disprove the hypothesis
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Control group
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Does not receive the variable
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Evolution
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the process of change that transforms life
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Biology
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The study of life
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Emergent properties
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At each new level , notice that there are novel properties that emerge, properties that were not components of the preceding level
"The whole is greater that the sum of its parts" |
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Reductionism
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Is the reduction of complex systems such as animals to simpler components that are easier to study
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Life's hierarchy of organization: bottom to top
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Atom- Molecule (DNA)- Organelle (Nucleus)- Cell (Nerve cell)- Tissue (Nervous tissue)- Organ (Brain)- Organ system (Nervous system)- Organism (Brown pelican)- Population (group of brown pelicans)- Community (All organisms on the Florida coast)- Ecosystem (Florida)- Biosphere
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The living and nonliving world is organized at many levels; each level provides the _____ for the next level.
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Building blocks
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Atom
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Smallest particle of an element
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Molecules
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Clusters of atoms held by chemical bond
Example DNA; H20 |
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Organelles
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Membrane-bound structures with specific functions
Example nucleus |
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Cells
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Living entities distinguished form their environment by membrane
Example Nerve cells |
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Life's hierarchy of organization: should be studied from bottom to top because
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indicates that living organisms first consist of atoms, them molecules etc
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Middle tier
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characterized by the organism which is composed of
Tissues Organs Organ systems *Multicellular organisms |
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Tissues
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Made of groups of similar cells
Example nervous tissue has nerve cells |
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Organs
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Made of tissues; provided specific functions for the organism
Brain |
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Organ System
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Are composed of organs; have specific function
Nervous system |
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Multicellular organisms
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Are composed of multiple organ systems
Nervous, circulatory, respiratory |
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The upper tier
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Population
Community Ecosystem Biosphere |
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Population
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All individuals of the same species living within a specific area
Group of brown pelicans |
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Community
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The array of (two or more) organisms/populations living and interacting in a particular ecosystem
All organisms on the Florida coast |
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Ecosystem
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all the organisms living in a particular area and its nonliving physical
components of the environment with which the organism interact (e.g. soil, air, water, sunlight) |
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Biosphere
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all the environment on Earth that support life – most land, water, and
lower atmosphere; is the largest level |
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Producers
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Photosynthetic organisms provide food
Plants |
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Photosynthesis
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6CO2 + 6H2O into C6H12O6 + 6O2 +H2O
use energy from sunlight to convert CO2 and H20 into sugar (C6H12O6) and oxygen (O2) |
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Consumers
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Organisms that eat plant or animals
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To be successful an ecosystem must accomplish two things
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Recycle chemicals necessary for life
Move energy through the ecosystem |
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Two distinct groups of cells
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Prokaryotic cells
Eukaryotic cells |
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Prokaryotic cells
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Simple and small
Bacteria |
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Eukaryotic cells
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Possess organelles separated by membranes
Plants, animals, and fungi |
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Regardless of the group studied cells are _______ and ______
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Enclosed by a membrane and use DNA as their genetic information
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DNA
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The genetic (hereditary) material of all cells, is the substance of genes, the units of inheritance that transmits information from parents to offspring
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Gene
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A discrete unit of DNA
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DNA structure
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Molecular structure accounts for its structure
Double helix Chains made made of 4 kinds of building blocks= bases= adenine, guanine, cytosine, thymine (A, G, C, T) Arrangement of these bases, encodes precise information in genes |
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4 kinds of building blocks of DNA
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adenine, guanine, cytosine, thymine (A, G, C, T)
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All living things share common properties
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Order
Regulation Growth and development Energy processing |
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Order
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The complex organization of living things
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Regulation
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An ability to maintain an internal environment consistent with life
Example internal body temp |
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Growth and development
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Consistent growth and development controlled by DNA
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Energy processing
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Acquiring energy and transforming it to a form useful for the organism
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Response to the environment
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an ability to respond to environmental stimuli
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Reproduction
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the ability to perpetuate the species
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Evolutionary adaptation
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acquisition of traits that best suit the organism to its environment
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Three domains (groups) of life
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Bacteria
Archaea Eukarya |
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Bacteria
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Consists of prokaryotes, and most are unicellular and microscopic
Most diverse and widespread prokaryotes Have different shapes |
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Archaea
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Like bacteria
Prokaryotic Most are unicellular and microscopic live in unusual places Example deep oceans, hot springs, and areas of high PH |
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Eukarya
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contains eukaryotes,
are eukaryotic and contain a nucleus and organelles Protists Fungi Plantae Animalia |
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Protists
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aquatic habitats
diverse single cell some make their own food (photosynthesis) Example Algae |
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Plantae
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Example plants
Multicellular Photosynthetic Have ridged cell walls made of cellulose |
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Fungi
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Decomposers
Break down remains of dead organisms Organic waste |
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Animals
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Ingest food
Are motile- moving or capable of moving spontaneously Cells lack rigid cell walls |
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Charles darwin published
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On the Origin of
Species by Means of Natural Selection |
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What are the 2 things accomplished by Charles Darwin's book?
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Presented evidence to support the idea of evolution
Proposed a mechanism for evolution called natural selection |
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Natural selection
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Editing mechanism
It result from exposure of heritable variations to environmental factors that favor some individuals over others |
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Evolution
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biology's core theme and explains unity and diversity of life
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Natural selection was inferred by connecting 2 observations
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individual variation- individuals in a population vary in many heritable traits
Over production of off spring- a population of any species has the potential to produce far more offspring than will survive to produce offspring of their own |
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Adaptions
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structures, physiological process, or behaviors
that aid in survival and reproduction Adaptations that are good for one environment may be poor in another |
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Energy and heat
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lost not recycled
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Double helix
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Two strand woven together
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Nucleotide
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• Chains made up of 4 kind of building blocks/bases
• Adenine, guanine, cytosine, thymine (A,G,C,T) • Deoxyribonucleic acid • Base |
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Shapes of bacteria
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• Rod shaped → bacillus
• Sphere → coccus (cocci) • Bunches or clusters → “staph” staphylococcus • Chains → strepto-coccus • Rod chains → strepto-baccilus |
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Strep throat is called
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streptococcus pyogenes
o Named after the shape of bacteria |
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Biology is a _____ science, and concepts of both ____ and ____ apply.
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multidisciplinary, chemistry and physics
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Chemicals
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make up our bodies and those of other organisms. They also make up the physical environment.
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to understand life it is important to understand the basic concepts of______.
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chemistry
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chemicals are at the ___ of biological hierarchy.
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Base level
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Chemicals are arranged into higher and higher levels of structural organization eventually...
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leads to formation of living organisms
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LIving organisms are composed of about __ chemical elements.
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25
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Matter
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Anything that occupies space and mass (weight)
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Matter is composed of
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chemical elements
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Element
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A substance that cannot be broken down to other substance by ordinary chemical means
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There are ___ elements in nature-- only a few exist in a pure state e.g. gold copper, carbon, oxygen
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92
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what elements make up 96.3% of the human body?
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Oxygen, Carbon, hydrogen, Nitrogen
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Life requires ___ essential elements called ___ elements.
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25, trace
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Trace elements are common ________.
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additives to food and water
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What are some trace elements that prevent disease?
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Iron (Fe) 0.004% of the body; needed for energy, transports oxygen
Iodine (I) 0.15 mg/day needed; is added to water to improve health; is an ingrident of a hormone produced by the thyroid gland Iodine deficiency results in goiter |
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Why are chemicals are added to food?
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helps preserve it
make it more nutritious makes it look better |
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Fluoride is added in municipal water to prevent?
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Tooth decay
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Vitamins consist of more that one element and are examples of _____.
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Compounds
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Compound
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a substance consisting of two or more different elements combined in a fixed ratio
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NaCl
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Sodium Chloride (salt)
compound of two elements sodium is a metal and chloride is a poisonous gas chemically combined , an edible compound emerges |
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Two hydrogen (H) and one Oxygen (O) combine to form?
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H2O
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4 elements found in DNA?
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carbon, hydrogen,
oxygen, and nitrogen |
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Sugar (glucose)
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Formic acid has C, H, and O (C6H12O6)
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Atom
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the smallest unit of matter that still retains the properties of an element
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Proton
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has a single positive charge
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Electron
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has a single negative charge
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Neutron
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is electrically neutral
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Mass number
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protons + neutrons
example 2 protons 2 Neutrons Mass number 4 |
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Why are atoms are electrically neutral?
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Because they have the same number of positive protons and negative electrons
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Helium has __ protons, __ neutrons, and __ electrons
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2 2 2
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Hydrogen has __ electrons and __ protons
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1 1
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Carbon has __ protons, __ neutrons, and __ electrons.
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6 6 6
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Neutrons and protons are packed in the atom's?
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nucleus
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The number of ___ is the atomic number.
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protons
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Mass number
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is the sum of protons and neutrons in the nucleus
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Although all atoms of an element have the same atomic number, some differ in _____.
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mass number
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Isotopes
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have the same numbers of protons and electrons but different numbers of neutrons (same atomic number)
different mass number or atomic weight |
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Radioactive
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unstable isotope that gives off energy
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Living cells cannot ____ between ____ of the same element.
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distinguish, isotopes
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When radioactive compounds are used in metabolic processes, they act as ___.
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Tracers- radioactivity can be detected by instruments
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Biological tracers are frequently used in
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medical diagnosis
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what is a sophisticated imaging instrument used to detect isotopes?
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(PET) position-emission tomography
detects the location of injected radioactive materials Useful in diagnosing heart disorders and cancer and in brain research |
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Dangers of using radioactive substances
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uncontrolled exposure can cause damage to some molecules in a living cell, especially DNA
Chemical bond are broken by emitted energy, which causes abnormal bonds to form |
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One of the most serious environmental threats of radioactivity is ______ from nuclear accidents. 2 examples
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Radioactive fallout
Research US at 3 mile island nuclear power Research Chernobyl nuclear power in Soviet Union |
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Electron ______ determines the chemical properties of an atom
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arrangement
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Only ___ are involved in chemical activity
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electrons
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Electron shells
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electrons occur in energy levels
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Information about the distribution of electrons is found in the ____.
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Periodic table of elements
1st shell 2nd shell 3rd shell |
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Electrons shells
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electrons are distributed about the nucleus of an atom
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___ atoms can accommodate more electrons than ____ ones can.
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larger, smaller
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First shell
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2 electrons
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2nd and 3rd shell
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holds up to 8 electrons
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valance shell
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outermost shell
will participate in a chemical reaction; this also has electrons which will be lost or will gain electrons |
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Atoms want to __ their outermost shell
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fill
to accomplish this, the atom can share, donate (loose), or receive electrons (gain) |
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Chemical bonds
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the result in attraction between atoms
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Ion
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is a atom or molecule with an electric charge resulting from a gain or loss of electrons
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When an electron is lost, a ___ charge results; when one is gained, a ___ charge results.
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positive, negative
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two ions with opposite charges___
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attract each other
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Ionic bond
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when the attraction holds ions together.
It is also a bond between a metal and non metal |
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T/ F
salt crystals are repeated, orderly arranged sodium and chloride ions |
T
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Covalent bond
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results when atoms share outer-shell electrons
or between two non-metals |
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Covalent bonds are ___ than ionic bonds
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stronger-- but stability varies
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Electron sharing produces
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molecules
example H2 (single bond) O2 (double bond) N2 (triple bond) |
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Most biological molecules contain ____ bonds
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covalent
examples proteins, sugar, cellulose |
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Unequal electron sharing creates ____.
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polar molecules
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Atoms in a _____ bonded molecule continually ______ for shared electrons
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covalently, compete
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Atoms with _ or _ valence shell electrons are ___
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6 or 7, hungry
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electronegativity
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Pull for shared electrons
example Oxygen, nitrogen, chlorine |
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Electropositive
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atoms with 1 or 2 valence shell electrons-- attraction is low. they usually lose their valence electrons to other atoms
Example hydrogen, potassium, sodium |
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unequal electron sharing creates
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polar molecules
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in molecules of only one element, the pull toward each atom is __, because
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equal, each atom has the same electronegativity
Example 2 hydrogen atoms |
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Non polar covalent bonds
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electrons are shared equally between the atoms
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Water has atoms with ____
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different electronegativity
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In water ___ attracts the shared electrons more strongly than ____. The result is a ___
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oxygen than hydrogen-- so the shared electrons spend more time near oxygen
Polar covalent ons |
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Polar molecules
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molecules with unequal distribution of charges
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Is water a polar molecule?
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Yes
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Hydrogen bonds are __ bond important in chemistry of life
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weak-- some chemical bonds are weaker than covalent bonds
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Hydrogen bond
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the positively charged region is always a hydrogen atom
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Free radical
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a molecule whose atoms have one or more unpaired electrons in their outer shell
Very unstable Steal electrons from the outer shells of other molecules |
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Free radicals attack the molecule and create a new free radical which begins a chain reaction which...
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destroy molecule improtant to life resulting in death
Examples Heart disease, Alzheimers, cancer aging |
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Causes of free radicals
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sun
x rays chemicals in auto exhaust industrial materials example mercury lead |
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Antioxidants
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get rid of free radicals
vitamins C and E fruit and vegetables body produces some |
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hydrogen bond make liquid water___
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cohesive
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cohesion
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molecules sticking together
stronger in water than other liquids |
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Cohesion is important to plants because
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useful in plants that depend upon water cohesion to help transport water and nutriets up to the plant
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Cohesion is related to ___
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surface tension- hydrogen bonds are responsible for surface tension
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surface tension
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a measure of how difficult it is to break the surface of a liquid
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perspiration
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When a substance evaporates, the
surface of the liquid remaining behind cools down as the molecules with the greatest energy (the hottest ones) leave |
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Ice is __ dense than liquid
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less- due to hydrogen bonding
Thats why it floats |
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when water freezes, each molecule forms a _______
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stable hydrogen bond with four neighbors
3D crystals result there is space between water molecules |
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Liquid water hydrogen bonds _______ and ____. Ice hydrogen bonds are ____.
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constantly break and re-form
Stable |
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Solution
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a liquid consisting of a uniform mixture of 2 or more substance
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Solvent
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the dissolving agent
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Solute
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the substance being dissolved
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water is a _____ that is fundamental to life processes
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versatile solvent- results from its polarity
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few water molecules can break apart into ions.
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– Some are hydrogen ions (H+)
– Some are hydroxide ions (OH–) – Both are extremely reactive – A balance between the two is critical for chemical processes to occur in a living organism |
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Acids
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chemicals other than water that contribute H+ to a
solution Example hydrochloric acid (HCI) stomach acid |
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An acidic solution has a higher concentration of ___
than ____. |
H+
OH– acid solution more H+ |
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Bases
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Some chemicals accept hydrogen ions and remove
them from solution |
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Bases- sodium hydroxide (NaOH)
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– For example, sodium hydroxide (NaOH) provides OH–
that combines with H+ to produce H2O (water) – This reduces the H+ concentration |
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PH scale
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(pH = potential of
hydrogen) is used to describe whether a solution is acidic or basic |
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pH rages from
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0 (most acidic) -14 (most basic)
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pH 7
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A solution that is neither
acidic or basic is neutral |
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Labial
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toward the cheek or lips of maxillary and mandibular teeth
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CO2 absorption lowers the pH of seawater
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which
decreases the concentration of carbonate ions which are required by corals and other organisms to produce calcium carbonate that makes up the skeletons or shells. |
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The formation of water from
hydrogen and oxygen is an example of a |
chemical reaction
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