| A | B |
|---|
| DNA | deoxyribonucleic acid: a long linear, double-helix shaped molecule found in the nucleus of a cell and formed from nucleotides; contains the information that determines inherited characteristics |
| complementary | an adjective used to describe two bases that always pair up together (ex. for DNA: A and T, C and G, and for RNA: A and U, C and G) |
| replication | a cell makes a copy of the DNA in its nucleus; |
| transcription | The synthesis of mRNA using a DNA template |
| translation | the decoding of an mRNA message from 3-base codons into amino acids to form a polypeptide chain |
| codon | three-nucleotide sequence of DNA or mRNA that codes for a single amino acid |
| amino acid | the smallest component of a protein; any one of 20 different organic molecules that combine into polypeptides that are folded into proteins |
| nucleic acid | an organic compound, either RNA or DNA, whose molecules are made up of one or two chains of nucleotides and carry genetic information |
| nucleotides | Basic units of DNA and RNA molecules, composed of a sugar, a phosphate, and one of 5 bases: DNA (A, T, G, C) and RNA (A, U, G, C) |
| mRNA | messenger RNA; the type of RNA that carries instructions from the DNA in the nucleus to the ribosome |
| tRNA | the type of RNA molecule that transfers amino acids to ribosomes during protein synthesis |
| mutate | A change, either spontaneous or by external factors, in the DNA of a cell, often through addition or deletion of one or more nucleotides; mutations in gametes (sex cells) can be inherited by future generations of organisms |
| mutation | an organism that has characteristics resulting from chromosomal alteration |
| prophase | the first stage of mitosis or meiosis in eukaryotic cells during which the nuclear envelope breaks down and the mitotic spindle begins to form |
| metaphase | the stage in mitosis or meiosis in which the duplicated chromosomes line up along the equatorial plate of the spindle |
| anaphase | the stage of meiosis or mitosis when chromosomes move toward opposite ends of the cell |
| telophase | the final stage of mitosis or meiosis, during which a nuclear membrane forms around each set of new chromosomes |
| diploid | a cell that contains both sets of homologous chromosomes, ex. body cells, somatic cells |
| haploid | a cell that contains only a one set of chromosomes and therefore only a single set of genes, ex. sex cells (ova, sperm) |
| cross-over | the process in which homologous chromosomes exchange portions of their genetic material during prophase I in meiosis |
| offspring | the immediate descendants of an organism |
| sexual reproduction | a type of reproduction in which two parents provide genetic material in gametes that combines and produces offspring that differ genetically from either parent |
| reproduce | to have offspring; to make more of a species; to add to a population |
| meiosis | a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of four genetically different gametes (sex cells) |
| mitosis | the stage of the cell cycle during which the cell's nucleus divides into two new nuclei and one copy of the DNA is distributed into each daughter cell |
| gene | a sequence on a molecule of DNA that codes for a protein and thus determines a trait |
| genetic | relating to traits passed down from birth through inheritance of DNA from parents and other direct ancestors |
| trait | a specific characteristic that an organism can pass on to its offspring through its genes |
| dominant | the relationship between two versions of a gene: if an individual receives two different alleles of a gene and only one allele is expressed; it is the dominant gene; the effect of the other allele, called recessive, is masked |
| recessive | a trait that is masked by the dominant allele of the gene; a trait that will only appear in the phenotype if an organism inherits two copies of the recessive allele |
| heterozygous | an organism that has two different alleles for a specific gene |
| homozygous | an organism that has two identical alleles for a specific gene |
| allele | alternate forms of a gene that are responsible for variations in traits (ex. eye color, length of toes) |
| phenotype | the physical traits that appear in an individual as a result of its genetic make up |
| genotype | the two letters used to represent the two alleles for a specific trait |
| characteristic | a physical attribute of an organism, such as hair color, height, color pattern; a genetic trait |
| inherited | traits in offspring that have been passed from their parents and ancestors through the genes |
| punnett square | a short hand way to predict the ratio of offspring that two parents might produce based on their genotypes |
| pedigree | a diagram that shows the occurrence of a genetic trait in several generations of a family |
| incomplete dominance | creates a blended phenotype in which both traits of the alleles are expressed, ex. a white allele and a red allele are both expressed so the flower appears pink in color |
| sex chromosomes | X and Y chromosomes; other chromosomes are homologous pairs. XX = female organism, XY = male organism |
| species | a taxonomic group whose members can interbreed and produce fertile offspring |
| native | plants or animals that are natural inhabitants in an environment; indigenous organisms to an ecosystem |
| function | the special, normal, or proper activity of an organ or a structure of an organism |
| structure | the arrangement of parts in an organism; the way an organism is put together as a whole |
| resource | any necessity of life, such as water, nutrients, light, food, or space; anything obtained from the environment to meet our needs or wants; ex: air, coal, water, wood |
| habitat | the type of environment in which an organism or population of organisms normally lives |
| survive | to continue to live and be a member of a population |
| endangered | when there are so few members of a species that it is in danger of dying out |
| extinct | no longer in existence; describes a species when the last individual of a population dies |
| niche | full range of physical and biological conditions in which an organism lives and the way in which the organism uses those conditions; organism's role, or job, in its habitat |
| diversity | the number of species present in a community as well as the relative abundance of each species |
| constraint | any factor that limits the performance of an organism or a system and restricts output |
| adaptation | an inherited characteristic that increases an organism's chance of survival |
| succession | the gradual and orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established |
| transformation | the act of changing in composition, structure, or appearance |
| natural selection | the principle that inherited trait variations that lead to longer survival and increased reproductive opportunites in an organism will most likely be passed on to succeeding generations |
| embryo | an organism in its early stage of development |
| evolution | the sequence of events involved in the adaptive development of a species or taxonomic group of organisms; change in a kind of organism over time; process by which modern organisms have descended from ancient organisms |
| divergent | populations evolving in different directions from a common ancestor |
| fossil | the preserved remains (or an impression) of a plant or animal that existed in the past |
| evidence | the collected body of data from observations and experiments used to support the conclusion of a report |
| trend | a pattern of change over time that is shown by data in part or all of the graph (ex. increasing, decreasing, or staying the same) |
| technology | the application of science for practical purposes; the use of tools, machines, materials, and processes to meet human needs and wants |
| investigation | a detailed examination procedure carried out to gather data about an object or event |
