Biology Final Vocab
About this set
Created by:
juliactress145 on June 16, 2010
Subjects:
Log in to favorite or report as inappropriate.
Order by
154 terms
Terms | Definitions |
|---|---|
 virus | package of nucleic acid wrapped in a protein coat that must use a host cell's machinery to reproduce itself |
| bacteriophage | A virus that infects bacteria |
| deoxyribonucleic acid | molecule responsible for inheritance |
| nucleotide | building block of nucleic acid polymers |
| nitrogenous base | single or double ring of carbon and nitrogen atoms with attached functional groups, found in nucleic acids |
| pyrimidine | single-ring nitrogenous base |
| purine | double-ring nitrogenous base |
| double helix | two strands of nucleotides wound about each other |
| DNA Replication | process of copying DNA molecules |
| DNA Polymerase | enzyme that makes the covalent bonds between the nucleotides of new DNA strands |
| ribonucleic acid | nucleic acid containing the sugar ribose |
| transcription | process by which a DNA template is used to produce a single-stranded RNA molecule |
| translation | process by which a sequence of nucleic acids in RNA is used to direct the production of a chain of specific amino acids |
| codon | in RNA, a three-base "word" that codes for one amino acid |
| messenger RNA | RNA Molecule transcribed from a DNA template |
| RNA Polymerase | transcription enzyme that links RNA nucleotides together |
| intron | internal noncoding region in RNA transcript |
| exon | coding region in RNA transcript |
| RNA splicing | process by which the introns are removed from RNA transcripts and the remaining exons are joined together |
| anticodon | in tRNA, a triplet of nitrogenous bases that is complementary to a specific codon in mRNA |
| transfer RNA | RNA that translates the three-letter codons of mRNA to amino acids |
| ribosomal RNA | RNA component of ribosomes |
| mutation | any change in the nucleotide sequence of DNA |
| mutagen | physical or chemical agent that causes mutations |
| genome | complete set of an organism's genetic material |
| histone | small protein that DNA wraps around |
| trisomy 21 | condition in which an individual has three number 21 chromosomes, resulting in Down syndrome |
| Down syndrome | general set of symptoms in people with trisomy 21 |
| nondisjunction | event during meiosis in which homologous chromosomes or sister chromatids fail to separate |
| duplication | change to a chromosome in which part of the chromosome is repeated |
| deletion | change to a chromosome in which a fragment of the chromosome is removed |
| inversion | change to a chromosome in which a fragment of the original chromosome is reversed |
| translocation | change to a chromosome in which a fragment of one chromosome attaches to a nonhomologous chromosome |
| transposon | genetic element that moves from one location to another in a genome |
| pedigree | family tree that records and traces the occurrence of a trait in a family |
| carrier | individual who has one copy of the allele for a recessive disorder and does not exhibit symptoms |
| genetic counselor | person trained to collect, analyze, and explain data about human inheritance patterns |
| plasmid | small, circular DNA molecule found in bacteria that is separate from the bacterial chromosome |
| restriction enzyme | enzyme that cuts sugar-phosphate bonds in the DNA backbone at specific points within particular nucleotide sequences in DNA |
| genomic library | complete collection of cloned DNA fragments from an organism |
| nucleic acid probe | radioactively labeled nucleic acid molecule used to tag a particular DNA sequence |
| genetically modified organism | organism that has acquired genetic material by artificial means |
| transgenic | genetically modified organism whose source of new genetic material is a different species |
| operon | cluster of genes and their control sequences |
| promoter | control sequence on an operon where RNA polymerase attaches to the DNA |
| operator | control sequence on an operon that acts as a switch, determining whether or not RNA polymerase can attach to the promoter |
| repressor | protein that binds to the operator and blocks attachment of RNA polymerase to the promoter |
| transcription factor | protein that regulates transcription by binding to promoters or to RNA polymerases |
| gene expression | transcription and translation of genes into proteins |
| cellular differentiation | increasing specialization in structure and function of cells during development of a multicellular organism |
| stem cell | cell with the potential to develop into one of several types of differentiated cell |
| homeotic gene | master control gene in many organisms that directs development of body parts |
| evolution | generation-to-generation change in the proportion of different inherited genes in a population that account for all of the changes that have transformed life over an immense time |
| adaptation | inherited characteristic that improves an organism's ability to survive and reproduce in a particular environment |
| descent with modification | process by which descendants of ancestral organisms spread into various habitats and accumulate adaptations to diverse ways of life |
| natural selection | process by which individuals with inherited characteristics well-suited to the environment leave more offspring than do other individuals |
| fossil | preserved remains or marking left by an organism that lived in the past |
| fossil record | chronological collection of life's remains in sedimentary rock layers |
| extinct | no longer existing as a living species on Earth |
| homologous structure | similar structure found in more than one species that share a common ancestor |
| vestigial structure | remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species |
| population | group of individuals of the same species living in a particular area at the same time |
| variation | difference among members of a species |
| artificial selection | selective breeding of domesticated plants and animals to produce offspring with desired genetic traits |
| gene pool | all of the alleles in all the individuals that make up a population |
| microevolution | evolution on the smallest scale—a generation-to-generation change in the frequencies of alleles within a population |
| Hardy-Weinberg Equilibrium | condition that occurs when the frequency of alleles in a particular gene pool remain constant over time |
| genetic drift | change in the gene pool of a population due to chance |
| gene flow | exchange of genes between populations |
| fitness | contribution that an individual makes to the gene pool of the next generation compared to the contributions of other individuals |
| antibiotic | medicine that kills or slows the growth of bacteria |
| biological species concept | definition of a species as a population or group of populations whose members can breed with one another in nature and produce fertile offspring |
| macroevolution | major biological changes evident in the fossil record |
| speciation | formation of new species |
| reproductive isolation | condition in which a reproductive barrier keeps two species from interbreeding |
| geographic isolation | separation of populations as a result of geographic change or migration to geographically isolated places. |
| adaptive radiation | evolution from a common ancestor of many species adapted to diverse environments |
| punctuated equilibrium | evolutionary model suggesting species often diverge in spurts of relatively rapid change, followed by long periods of little change |
| embryology | study of multicellular organisms as they develop from fertilized eggs to fully formed organisms |
| geologic time scale | Earth's history organized into four eras: Precambrian, Paleozoic, Mesozoic, and Cenozoic |
| radiometric dating | determination of absolute ages of rocks and fossils through calculations based on a radioactive isotope's fixed rate of decay |
| half-life | time it takes for 50% pf a radioactive isotope sample to decay |
| continental drift | motion of continents about Earth's surface on plates of crust floating on the hot mantle |
| mass extinction | episode of great species loss |
| taxonomy | identification, naming, and classification of species |
| binomial | two-part Latin name of a species |
| phylogenetic tree | branching diagram, suggesting evolutionary relationships, that classifies species into groups within groups |
| convergent evolution | process in which unrelated species from similar environments have adaptations that seem very similar |
| analogous structures | similarities among unrelated species that result from convergent evolution |
| derived character | homologous characteristic that unites organisms as a group |
| cladogram | phylogenetic tree constructed from a series of two-way branch points, suggesting ancestral relationships among species |
| matter | anything that occupies space and has mass |
| element | pure substance that cannot be broken down into other substances by chemical or physical means |
| trace element | element critical to health that makes up less than 0.01 percent of body mass |
| compound | substance containing two or more elements chemically combined in a fixed ratio |
| atom | smallest particle of an element |
| proton | subatomic particle with a single unit of positive electric charge |
| electron | subatomic particle with a single unit of negative electric charge |
| neutron | subatomic particle that has no charge |
| nucleus | in an atom, the central core that contains protons and neutrons |
| atomic number | number of protons in an atom;s nucleus |
| isotope | one of several forms of an element, each containing the same number of protons in their atoms but a different number of neutrons |
| radioactive isotope | isotope in which the nucleus decays over time, giving off radiation in the form of matter and energy |
| ionic bond | chemical bond that occurs when an atom transfers an electron to another atom |
| ion | atom that has become electrically charged as a result of gaining or losing an electron |
| covalent bond | chemical bond that forms when two atoms share electrons |
| molecule | two or more atoms held together by covalent bonds |
| chemical reaction | breaking of old and formation of new chemical bonds that result in new substances |
| reactant | starting material for a chemical reaction |
| product | material created as a result of a chemical reaction |
| polar molecule | molecule in which opposite ends have opposite electric charges |
| hydrogen bond | bond created by the weak attraction of a slightly positive hydrogen atom to a slightly negative portion of another molecule |
| cohesion | tendency of molecules of the same kind to stick to one another |
| adhesion | attraction between unlike molecules |
| thermal energy | total amount of energy associated with the random movement of atoms and molecules in a sample of matter |
| temperature | measure of the average energy of random motion of particles in a substance |
| solution | uniform mixture of two or more substances |
| solvent | substance in a solution that dissolves the other substance and is present in the greater amount |
| solute | substance in a solution that is dissolved and is present in a lesser amount |
| aqueous solution | solution in which water is the solvent |
| acid | compound that donates H+ ions to an aqueous solution and measures less than 7 on the pH scale |
| base | compound that removes H+ ions from and aqueous solution and that measures more than 7 on the pH scale |
| pH scale | a range of numbers used to describe how acidic or basic a solution is |
| buffer | substance that maintains a fairly constant pH in a solution by accepting H+ ions when their levels rise and donating H+ ions when their levels fall |
| organic molecule | carbon-based molecule |
| inorganic molecule | non-carbon-based molecule |
| hydrocarbon | organic molecule composed of only carbon and hydrogen atoms |
| functional group | group of atoms within a molecule that interacts in predictable ways with other molecules |
| hydrophilic | attracts water molecules |
| monomer | small molecular unit that is the building block of a larger molecule |
| polymer | long chain of small molecular units |
| carbohydrate | organic compound made of sugar molecules |
| monosaccharide | sugar containing one sugar unit |
| disaccharide | sugar with two monosaccharides |
| polysaccharide | long polymer chain made up of simple sugar monomers |
| starch | polysaccharide in plant cells that consists entirely of glucose monomers |
| glycogen | polysaccharide in animal cells that consists of many glucose monomers |
| cellulose | polysaccharide consisting of glucose monomers that reinforces plant-cell walls |
| lipid | one of a class of water-avoiding compounds |
| hydrophobic | avoids water molecules |
| fat | organic compound consisting of a three-carbon backbone attached to three fatty acids |
| saturated fat | fat in which all three fatty acid chains contain the maximum possible number of hydrogen atoms |
| unsaturated fat | fat with less than the maximum number of hydrogens in one or more of its fatty acid chains |
| steroid | lipid molecule with four fused carbon rings |
| cholesterol | steroid molecule present in the plasma membranes of animal cells |
| protein | polymer constructed from a set of 20 amino acid monomers |
| amino acid | monomer that makes up proteins |
| polypeptide | chain of linked amino acids |
| denaturation | loss of normal shape of a protein due to heat or other factor |
| activation energy | minimum amount of energy required to trigger a chemical reaction |
| catalyst | agent that speeds up chemical reactions |
| enzyme | specialized protein that catalyzes the chemical reactions of a cell |
| substrate | specific reactant acted on by an enzyme |
| active site | region of an enzyme into which a particular substrate fits |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.