AP Biology Terminologies

AP Biology Terminologies Ligands - A molecule that binds specifically to a receptor site of another molecule. Local Regulators - A secreted molecule that influences cells near where it is secreted. Biotic - Describes living factors in the environment. Abiotic - Non-living things keystone species - a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically. analogous structures - Body parts that share a common function, but not structure vestigial structures - A structure that is present in an organism but no longer serves its original purpose homologous structures - Structures in different species that are similar because of common ancestry. Positive Feedback - A type of regulation that responds to a change in conditions by initiating responses that will amplify the change. Takes organism away from a steady state. Negative Feedback - A type of regulation that responds to a change in conditions by initiating responses that will counteract the change. Maintains a steady state. Stimulus - any event or situation that evokes a response Stimuli - Changes in the environment Neurotransmitters - Chemicals that transmit information from one neuron to another neurosecretory cells - Neurons of the hypothalamus that secrete neurohormone rather than neurotransmitter Centromere - the region of the chromosome that holds the two sister chromatids together during mitosis IPMAT-C - Interphase, Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis Interphase - Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases G1 phase - stage of interphase in which cell grows and performs its normal functions G1 checkpoint - checks to see if cell size is adequate; chromosomes replication is successfully completed and checks for DNA errors G0 phase - A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly. G2 phase - The Second stage of interphase in which cell duplicates its cytosol and organelles G2 checkpoint - The cell checks to make sure the DNA is copied correctly Mitosis - cell division in which the nucleus divides into nuclei containing the same number of chromosomes Prophase (mitosis) - chromosomes condense and spindle apparatus begins to form Metaphase (mitosis) - Chromosomes line up in the middle of the cell Anaphase (Mitosis) - cell elongates and sister chromatids are pulled apart toward the poles Telophase (mitosis) - chromosomes begin to uncoil, spindles break down, and new nuclear membrane forms. Cytokinesis in animal cells - The cell membrane is drawn inward until the cytoplasm is pinched into two nearly equal parts cytokinesis in plant cells - divide from inside out using a cell plate in middle of cell Growth factor - A protein secreted by certain body cells that stimulates other cells to divide density-dependent inhibition - The arrest of cell division occurs when cells touch one another. anchorage dependent - The requirement that a cell must be attached to a solid surface in order to initiate cell division. Mutations - changes in the genetic material Deletion - A change to a chromosome in which a fragment of the chromosome is removed. Duplication - When a fragment from one chromosome joins to a sister chromatid or homologous chromosome Inversion - When a fragment reattaches to the original chromosome but in the reverse direction Translocation - The attachment of a chromosomal fragment to a nonhomologous chromosome Translation - Process by which mRNA is decoded and a protein is produced Transcription - synthesis of an RNA molecule from a DNA template DNA polymerase - Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule RNA polymerase - enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template p35 - tumor suppressor protein that is an IDP, gets highly mutated in cancer patients, transcription factor serves as an interactive hub