| Term | Definition |
|---|
| ATP | molecule that stores the useable energy created during cellular respiration |
| atom | particle made up of protons, neutrons, and electrons |
| compound | the chemical combination of 2 or more elements in specific amounts |
| metabolism | all of the chemical reactions that build or break down materials within an organism |
| axon | long fiber that carries electrical impulses away from the nerve cell body |
| organelle | a specialized cell structure that performs a specific job within a cell |
| carbon dioxide | gas that is a reactant of photosynthesis and a waste product of cellular respiration |
| antibody | specialized protein made by the body to fight off future infections from a disease-causing organism |
| transcription | copying the code from DNA onto mRNA |
| codon | three mRNA nucleotides that code for a specific amino acid |
| translation | process by which a ribosome uses the code on mRNA to make proteins |
| nucleotide | building block of a nucleic acid (DNA and RNA) |
| chromatin | DNA that is coiled around proteins |
| amino acid | building block of a protein |
| mRNA | messenger RNA; type of RNA that carries instructions from DNA in the nucleus to the ribosome |
| polypeptide | synonym for protein; chain of amino acids |
| replication | process in which DNA is duplicated |
| rRNA | ribosomal RNA; type of RNA that makes up part of the ribosome |
| mutation | a change or error in the DNA sequence |
| tRNA | transfer RNA; type of RNA that carries amino acids to the ribosome |
| cell division | division of a parent cell into two identical daughter cells |
| centriole | structure that helps to form the spindle |
| spindle | microtubule structure that separates chromosomes during mitosis |
| cell cycle | cell grows, prepares to divide, then divides to start growth process again; interphase + M phase |
| telophase | last phase of mitosis, chromosome are in two new cells and nuclear membranes start to reform |
| interphase | cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases |
| mitosis | division of the nucleus or chromosomes |
| metaphase | phase of mitosis in which chromosomes line up in the center of the cell |
| prophase | first phase of mitosis in which chromosomes become visible and nuclear membraine disappears |
| cytokinesis | division of the cytoplasm (cytosol and organelles) |
| anaphase | phase of mitosis in which sister chromatids are pulled to opposite sides of the cell |
| cancer | uncontrolled cell division |
| G1 phase | stage of interphase in which cell grows and performs its normal functions |
| S phase | stage of interphase in which DNA is replicated |
| G2 phase | stage of interphase in which cell duplicates its cytosol and organelles |
| gamete | sex cell, sperm or egg |
| meiosis | type of cell division that creates gametes; cell divides twice to create four cells that are genetically unique |
| crossing-over | process by which homologous chromosomes exchange pieces, resulting in greater genetic variety |
| plasma membrane | thin flexible barrier that regulates what enters and exits the cell; composed of two layers of lipids |
| nuclear envelope | membrane surrounding the nucleus |
| nucleus | contains the DNA and controls all of the cell's acitivities |
| nucleolus | helps to assemble ribosomes |
| cytoplasm | material between the cell membrane and the nucleus |
| mitochondrion | breaks down food to make ATP |
| endoplasmic reticulum | internal transport system of the cell, modifies proteins, and synthesizes lipids |
| Golgi apparatus | stack of membranes that modify proteins and creates "packages" to send them to other locations |
| lysosome | filled with enzymes to breakdown dead cell parts and foreign objects; only found in animal cells |
| ribosome | synthesizes proteins |
| vacuole | stores water and nutrients for the cell; very large in plant cells |
| cell wall | provides structure and support around cell membrane of plants, fungi, and some bacteria |
| chloroplast | uses sunlight to make carbohydrates in plants, some bacteria and protists |
| centriole | organize the spindle fibers to separate chromosomes during animal cell mitosis |
| cytoskeleton | network of proteins in the cytoplasm that help cell maintain its shape |
| cilium | hairlike projections that help some cells move |
| flagellum | whiplike structure some cells use for propulsion |
| pseudopod | projection of cytoplasm that some protists use for movement and feeding |
| prokaryote | cell without a nucleus, it contains a cell membrane, cytoplasm, and ribosomes; bacteria |
| eukaryote | cell with a nucleus and membrane bound organelles; animals, plants, protists, fungi |
| gene | section of DNA that codes for a protein and determines a trait |
| trait | specific characteristic that varies from one individual to another |
| allele | form of a gene |
| dominant | trait that will show up in an organism's phenotype if gene is present |
| recessive | trait that will only appear in the phenotype if organism inherits two of them; covered up by the dominant gene |
| segregation | separation of alleles during meiosis or gamete formation |
| gamete | sex cell; sperm or egg |
| hybrid | offspring of a cross between parents with different traits; heterozygous |
| true-breeding | inherited two identical alleles for a trait; homozygous or purebred |
| probability | likelihood an event will occur |
| phenotype | physical characteristics of an organism |
| Punnett square | diagram that shows the possible results of a genetic cross; parents' gametes on top and left, offsprings' genotypes inside |
| genotype | genetic makeup of an organism |
| homozygous | has two identical alleles for a particular trait; true-breeding or purebred, ex. PP or pp |
| heterozygous | has two different alleles for a particular trait; hybrid, ex. Pp |
| independent assortment | principle that genes do not influence each other's inheritance because they are separated independently during meiosis |
| multiple alleles | three or more alleles exist for a particular trait |
| incomplete dominance | creates a blended phenotype; one allele is not completely dominant over the other |
| polygenic trait | trait controlled by two or more genes; shows a wide variety of phenotypes |
| codominance | both genes contribute to the phenotype of the organism, ex. spotted or striped |
| nondisjunction | error in meiosis in which homologous chromosomes don't separate; gametes end up with wrong number of chromosomes |
| sex-linked trait | trait related to a gene that is found on the X or Y chromosomes |
| evolution | change over time; process by which modern organisms descended from ancient organisms |
| theory | well-tested, well-supported explanation that unifies a broad range of observations |
| fossil | preserved remains of an ancient organism |
| natural variation | differences among individuals of a species; results from mutation and sexual reproduction |
| struggle for existence | competition between organisms for food and space |
| fitness | ability of an organism to survive and reproduce in its environment |
| adaptation | inherited characteristic that increases an organism's chance of survival |
| survival of the fittest | individuals that are better suited to their environment survive and reproduce most successfully; natural selection |
| natural selection | individuals that are better suited to their environment survive and reproduce most successfully; survival of the fittest |
| common descent | principle that all living things have a common ancestor |
| homologous structure | structures that have different mature forms but develop from the same embryonic tissues |
| vestigial organ | organ so reduced in size, it does not serve an important function; may be homologous to structures in other organisms |
| gene pool | combined genetic information of of all the members of a population |
| allele frequency | how often a form of a gene appears in a gene pool |
| species | two organisms that are so similar they can interbreed in nature and produce fertile offspring |
| speciation | formation of a new species as a result of reproductive isolation |
| reproductive isolation | separation of species that prevents them from interbreeding and producing fertile offspring |
| behavioral isolation | type of reproductive isolation in which two organisms have different mating rituals that prevent them from interbreeding |
| geographic isolation | type of reproductive isolation in which two populations are separated by geographic barries like mountains or bodies of water |
| temporal isolation | type of reproductive isolation in which two organisms reproduce at different times |
| biodiversity | variety of organisms that exist in the biosphere |
| taxonomy | classification of organisms |
| binomial nomenclature | two part scientfic name for an organism; its genus is listed first, followed by its species |
| genus | first part of an organism's scientific name |
| kingdom | second largest taxonomic group; there are six - animalia, plantae, protista, eubacteria, archaebacteria, fungi |
| domain | most inclusive taxonomic group, larger than kingdom; three exist - bacteria, archaea, eukaryota |
| Protista | a single celled plant or animal, ex. amoeba, paramecia, euglena |
| molecular clock | model that uses DNA comparisons to estimate how long two organisms evolved from a common ancestor |
| phylogenetic tree | diagram showing evolutionary relationships of organisms with a common ancestor; resembles a tree |
| cladogram | diagram that shows the evolutionary relationships among organisms based on derived characters; resembles a timeline |
| divergent evolution | pattern of evolution in which two species become more and more dissimilar |
| Fungi | kingdom of hetertrophs that obtain nutrients through absorption, ex. mushrooms, yeasts |
| Eukaryota | domain of organisms that contain nuclei, includes animals, plants, fungi, and protists |
| ecology | study of interactions between organisms and their environment |
| ecosystem | all the organisms in a particular location, including their non-living environment |
| species | two organisms that are so similar they can interbreed in nature and produce fertile offspring |
| population | members of a species in a defined area |
| biosphere | part of Earth that living organisms inhabit |
| community | populations of different organisms living in a defined area |
| autotroph | organism that makes its own food using sunlight or chemicals; producer |
| producer | organism that makes its own food using sunlight or chemicals; autotroph |
| photosynthesis | using sunlight and carbon dioxide to make food (carbohydrates) |
| chemosynthesis | using inorganic chemicals to make food (carbohydrates) |
| heterotroph | organism that relies on other organisms for food; consumer |
| consumer | organism that relies on other organisms for food; heterotroph |
| herbivore | consumer that eats plants |
| carnivore | consumer that eats animals or meat |
| omnivore | consumer that eats both plants and animals |
| decomposer | organism that breaks down and absorbs nutrients from dead organisms |
| detritivore | organism that feeds on animal and plant remains that it did not capture; scavenger |
| food chain | series of steps in which organisms transfer energy by eating and being eaten |
| food web | network of all the food chains in an ecosystem |
| trophic level | step in a food chain, food web, or ecological pyramid |
| energy pyramid | diagram that shows the energy available to each trophic level in an ecosystem; 10% is passed on to upper levels, the rest is lost as heat |
| biogeochemical cycle | process in which nutrients are recycled through the biosphere, ex. carbon, nitrogen, and phosphorous |
| evaporation | process by which liquid water turns into a gas (water vapor) when heated |
| transpiration | evaporation of water from plant leaves |
| nutrient | chemical that an organism needs to live |
| nitrogen fixation | process in which bacteria convert nitrogen gas into nitrogen compounds plants can use to make proteins |
| denitrification | conversion of nitrates in the soil by bacteria into nitrogen gas |
| greenhouse effect | heat reatined by the the gases of the Earth's atmosphere to maintain the Earth's temperature range |
| biotic factor | living factors or organisms that affect an ecosystem |
| abiotic factor | non-living factor that affects an ecosystem |
| habitat | where an organism lives |
| resource | anything that an organism needs to live, ex. food, water, space |
| predation | interaction in which one organism hunts, captures, and feeds on another organism |
| symbiosis | relationship in which two species live closely together |
| mutualism | symbiotic relationship in which both organisms benefit |
| commensalism | symbiotic relationship in which one organism benefits and the other organism is not affected |
| parasitism | symbiotic relationship in which one organism benefits and the other organism is harmed |
| population density | number of individuals per unit area |
| immigration | individuals joining a population |
| emigration | individuals leaving a population |
| carrying capacity | largest number of individuals of a population that the environment can support |
| invasive (non-native) species | plants and animals that have migrated to areas where they did not originate; often displace native species by outcompeting them for resources |
| biodiversity | the variety of all living things in the biosphere |
| cellular respiration | process that breaks down food to make ATP and release carbon dioxide as waste |
| chemical bond | link formed by two electrons that binds atoms together; where the energy in a compound is stored |
| pH scale | measurement system used to indicate how acidic or basic a substance is; measures the concentration of H+ ions |
| acid | compound that release H+ ions in solution; pH less than 7 |
| base | compound that releases OH- ions in solution; pH greater than 7 |
| monomer | building block or small unit of a polymer; can be linked into chains |
| polymer | large molecule made up of smaller building blocks or monomers |
| carbohydrate | contains carbon, hydrogen, and oxygen; main source of energy for body, commonly end in "ose" |
| monosaccharide | building block of a carbohydrate; simple sugar |
| polysaccharide | large carbohydrate made up of monosaccharides, ex. starch and glycogen |
| lipid | huge molecule that contains carbon, hydrogen, and a little oxygen; includes fats, oils, and waxes |
| fatty acid | with glycerol, make up the building blocks of lipids |
| glycerol | with fatty acids, make up the building blocks of lipids |
| RNA | single stranded nucleic acid used for protein synthesis |
| DNA | double stranded nucleic acid that stores and transmits genetic information |
| protein | contains carbon, hydrogen, oxygen, and nitrogen; makes up cell/body structures and enzymes |
| nucleotide | building block or monomer of a nucleic acid; commonly recognized by its nitrogen bases as A, T, C, or G |
| amino acid | building block or monomer of a protein |
| nucleic acid | contains carbon, hydrogen, oxygen, nitrogen, and phosphorous; involved in protein synthesis |
| chemical reaction | process that changes one set of chemicals into another set of chemicals |
| reactant | chemical that enters a chemical reaction |
| product | chemical that results from a chemical reaction |
| activation energy | energy needed to start a reaction |
| catalyst | substance that speeds up the rate of a chemical reaction |
| enzyme | specialized protein that speeds up a chemical reaction by decreasing activation energy; typically end in "ase" |
| substrate | reactant in a chemical reaction that happens in a living thing |
| denaturation | when an enzyme changes shape and no longer functions due to high temperatures or wrong pH |
| organic compound | compound that contains carbon bonded to hydrogen and is found in living things |
| starch | polysaccharide made up of a chain of glucose molecules; food storage molecule for plants |
| glycogen | compound used by animals to store carbohydrates in the liver and skeletal muscles |
| glucose | simple sugar that is used to make ATP through cellular respiration |
| cellulose | polysaccharide that is the main component of plant |
| hemoglobin | specialized protein that carries oxygen on red blood cells |
| insulin | protein hormone that helps to decrease blood sugar |
| cholesterol | specialized lipid that is used in cell membranes and making hormones |
| digestive system | body system the breaks down food and absorbs nutrients |
| pharynx | the throat; last place food and air mix |
| esophagus | muscular tube connecting the pharynx to the stomach |
| stomach | muscular sac that churns food and secretes hydrochloric acid to start breaking down proteins |
| small intestine | organ that completes the chemical digestion of food and absorbs the nutrients |
| large intestine | organ that absorbs water from undigested material |
| chemical digestion | the digestion process in which enzymes are used to break foods into their smaller chemical buiding blocks |
| mechanical digestion | the physical breakdown of food into smaller pieces |
| rectum | the lower part of the large intestine where feces are stored |
| circulatory system | body system consisting of the heart and blood vessels that circulate blood through the body |
| atria | two upper chambers of the heart pump blood into the ventricles |
| ventricles | two lower, muscular chambers of the heart which pump blood to the lungs and the rest of the body |
| artery | thick-walled muscular blood vessel that carries blood away from the heart |
| vein | blood vessel that carries blood toward the heart when pumped by skeletal muscles |
| capillary | tiny, thin-walled blood vessel where substances (gases and nutrients) are exchanged between the blood and the body cells |
| red blood cells | blood cells containing hemoglobin that carry oxygen through the bloodstream |
| kidneys | organs that filter nitrogen wastes from blood to make urine |
| liver | organ that makes bile to break down fats; also filters poisons and drugs out of the blood |
| excretion | elimination of wastes from the body (urine, carbon dioxide, sweat) |
| respiratory system | system responsible for taking in oxygen and releasing carbon dioxide using the lungs |
| larynx | voice box; passageway for air moving from pharynx to trachea; contains vocal cords |
| trachea | windpipe; airway connecting the pharynx to the bronchi |
| alveoli | thin-walled microscopic air sacs in the lungs where the exchange of oxygen and carbon dioxide takes place |
| spinal cord | cord of nerve tissue that conducts messages between the brain and the peripheral nerves |
| sensory neurons | neurons that carry sensory information from receptors to the central nervous system |
| motor neurons | neurons that carry outgoing information from the central nervous system to the muscles and glands |
| neuron | nerve cell; conducts electrical signals |
| skeletal muscle | voluntary, striated, multi-nucleate muscle that moves bones |
| smooth muscle | involuntary muscle found in internal organs |
| cardiac muscle | type of muscle found in the heart which generates its own electrical signal to contract |
| cartilage | tough, flexible tissue that covers the ends of bones and decreases friction |
| ligament | band of connective tissue that holds the bones together |
| tendon | a band of fibrous tissue that connects muscle to bone |
| bone marrow | soft tissue found in the center of bone that produces blood cells |
| endocrine system | collection of glands that secrete hormones into the blood which regulate growth, development, and homeostasis |
| hormone | chemical messengers secreted by glands into the blood |
| gland | an organ that secretes hormones into the bloodstream |
| nervous system | consists of brain, spinal cord, and nerves and regulates the body's responses to internal and external stimuli |
| homeostasis | the process by which organisms keep their internal environment relatively stable |
| negative feedback loop | an opposite action to what is occurring in the body to regain homeostasis, ex. if body temperature rises too high, body tries to lower it |
| pulmonary circulation | circulation from the right side of the heart to the lungs and back to the left side of the heart |
| systemic circulation | circulation of oxygenated blood from the left side of the heart to the body and back to the right side of the heart |
| diffusion | movement of molecules across a membrane from high to low concentration without energy |
| concentration gradient | difference in concentration of a substance on two sides of a membrane |
| osmosis | movement of water across a membrane from high to low concentration without energy |
| semi-permeable | characteristic of a cell membrane which allows some molecules to pass through but not others |
| impermeable | molecules are not able to pass through the membrane |
| facilitated diffusion | movement of molecules through protein channels in the membrane from high to low concentration |
| active transport | movement of molecules through protein channels in the membrane from low to high concentration requiring energy (ATP) |
| passive transport | movement of molecules across a membrane from high to low concentration without energy, ex. diffusion, osmosis, facilitated diffusion |
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