AP Biology 2023 with verified questions and answers

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 Protein Kinase An enzyme that activates another molecule by phosphorylating it. Protein Kinase Signal Cascade A type of intracellular signaling where a series of protein Kinase add a phosphate group to the next protein in the cascade Oncogenes cancer causing genes Proto-oncogenes normal cellular genes that are important regulators of normal cellular processes, they promote growth. alterations in the expression of these cells result in oncogenes Carcinogen A cancer-causing substance Mutagen A chemical or physical agent that interacts with DNA and causes a mutation. Pathogen a bacterium, virus, or other microorganism that can cause disease. immune system A system (including the thymus and bone marrow and lymphoid tissues) that protects the body from foreign substances and pathogenic organisms by producing the immune response innate immunity Immunity that is present before exposure and effective from birth. Responds to a broad range of pathogens. Phagocytosis A type of endocytosis in which a cell engulfs large particles or whole cells inflammatory response An innate body defense in vertebrates caused by a release of histamine and other chemical alarms signal that triggers an increase in blood flow, a local increase in white blood cells, and fluid leakage from the blood - Results in Redness, heat, and swelling Adaptive immunity A vertebrate-specific defense that is activated only after exposure to an antigen and is mediated by lymphocytes lymph nodes an organ that filters lymph and that is found along the lymphatic vessels Passive Immunity Temporary immunity obtained by acquiring ready-made antibodies Active Immunity Immunity conferred by recovering from an infectious disease or by receiving a vaccine. Antigen A foreign molecule that evoke an adaptive immune response Antibody A protein dissolved in blood plasma that attaches to a specific kind of antigen that helps counter the effects of the antigen humoral immune response The type of specific immunity brought about by antibody-producing B-cells cell-mediated immune response The type of specific immunity brought about by T-cells; fights body cells infected with pathogens Clonal selection The production of a lineage of genetically identical cells that recognize and attack the specific antigen that stimulate their proliferation Memory Cells A clone of long-lived lymphocytes formed during the primary immune response; remains in a lymph node until activated by exposure to the same antigen that triggered its formation: when activated, a memory cell forms a large clone that mounts the secondary immune response Primary immune response the initial immune response to an antigen, which appears after a lag of several days Secondary immune response Immune response after the body has already been exposed to a specific antigen. Response is faster, of greater magnitude, and more prolonged. Monoclonal Antibodies (mAb) An antibody secreted by a clone of cells and therefore specific for the one antigen that triggered the development of the clone B cells Cells manufactured in the bone marrow that create antibodies for isolating and destroying invading bacteria and viruses. Macrophages Found within the lymph nodes, they are phagocytes that destroy bacteria, cancer cells, and other foreign matter in the lymphatic stream. Helper T-cells T cells that help the immune system by increasing the activity of killer cells, stimulating the suppressor T cells, and may help stimulate B-cells to produce antibodies Cytoxic T-cells A type of lymphocyte that attacks body cells infecteed with pathogens Killer T-cells Lymphocytes that use enzymes to destroy the cell membranes of bacteria and other foreign invaders. Antigen-presenting cells (APCs) One of a family of white blood cells that ingests a foreign substance or a microbe and attaches antigenic portions of the ingested material to its surface, thereby displaying the antigens to a helper T-cell Insulin A protein hormone synthesized in the pancreas that regulates blood sugar levels by facilitating the uptake of glucose into tissues Glucagon A hormone secreted by the pancreatic alpha cells that increases blood glucose concentration Type I Diabetes Insulin Dependent; Results when the pancreas does not produce insulin Type II Diabetes Non-Insulin Dependent; Results when body cells fail to respond to insulin Hypoglycemia An Abnormally low level of glucose in the blood that results when the pancreas secrets too much insulin into the blood Microevolution Change in allele frequencies in a population over generations. Macroevolution Evolutionary change above the species level. Speciation Formation of new species homologous structures Structures in different species that are similar because of common ancestry. analogous structures Body parts that share a common function, but not structure Directional Selection Natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals. Disruptive Selection natural selection in which individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle of the curve Stabilizing Selection form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve Generalist a species with a broad niche that can tolerate a wide range of conditions and can use a variety of resources Specialists species that have narrow niches R-selected species Species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period. K-selected species Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age. Natural Selection A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. What does natural selection require? Genetic Variation and Environmental Pressures that give some individuals some an advantage Sexual Selection Natural selection for mating success. intersexual selection Selection whereby individuals of one sex (usually females) are choosy in selecting their mates from individuals of the other sex; also called mate choice. intrasexual selection competition among individuals of one sex (often males) for mates of the opposite sex sexual dimorphism Differences in physical characteristics between males and females of the same species. Genetic Drift A change in the allele frequency of a population as a result of chance events rather than natural selection. Founder Effect genetic drift that occurs after a small number of individuals colonize a new area Bottleneck Effect Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population. horizontal gene transfer The transfer of genes from one genome to another through mechanisms such as transposable elements, plasmid exchange, viral activity, and perhaps fusions of different organisms. Molecular Biology The study of the molecular basis of genes and gene expression; molecular genetics. Biogeography Study of past and present distribution of organisms Homology Similarity in characteristics resulting from a shared ancestry. Strata layers of rock Evolutionary Tree A branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms. Hardy-Weinberg Principle principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change Hardy-Weinberg equilibrium the condition that occurs when the frequency of alleles in a particular gene pool remains constant over time: - Very Large Population - No gene flow between populations -No Mutations - Random Mating -No Natural Selection Balancing Selection Natural selection that maintains stable frequencies of two or more phenotypic forms in a population. Frequency-Dependent Selection selection in which the fitness of a phenotype depends on how common the phenotype is in a population Biological Species Concept Definition of a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce viable, fertile offspring with members of other such groups. Reproductive Isolation condition in which a reproductive barrier keeps two species from interbreeding Hybrids Offspring of crosses between parents with different traits Morphological Species Concept A definition of species in terms of measurable anatomical criteria. Ecological Species Concept A definition of species in terms of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment. Phylogenetic Species Concept A definition of species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life. Prezygotic Barriers A reproductive barrier that impedes mating between species or hinders fertilization if interspecific mating is attempted - Temporal, Habitat, Behavioral, Mechanical, and Gametic Temporal Isolation Breeding occurs at different times of the day or different seasons Habitat Isolation Two species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers Behavioral Isolation isolation between populations due to differences in courtship or mating behavior Mechanical Isolation Differences in physical structures prevent successful mating Gametic Isolation Sperm of one species may not be able to fertilize eggs of another species Postzygotic Barriers A reproductive barrier that prevents hybrid zygotes produced by two different species from developing into viable, fertile adults -Reduced Hybrid Viability, Reduced Hybrid Fertility, and Hybrid Break Down Reduced Hybrid Viability The development or survival of hybrids is impaired Reduced Hybrid Fertility Hybrids fail to produce functional gametes Hybrid Break Down offspring of hybrids are weak or infertile Allopatric Speciation The formation of new species in populations that are geographically isolated from one another. Sympatric Speciation The formation of new species in populations that live in the same geographic area Polyploidy An organism that has more than two complete sets of chromosomes as a result of an accident of cell division Triploidy (3n) three sets of chromosomes Tetraploidy (4n) four sets of chromosomes Hybrid Zone a geographic region in which members of different species meet and mate, producing at least some offspring of mixed ancestry Reinforcement of Hybrid Zone -Strengthening of reproductive barriers because hybrids are less fit than members of their parent species -Hybrids gradually seize to be formed Fusion (hybrid zone) reproductive barriers weaken until the two species become one Stability of Hybrid Zone fit hybrids continue to be produced Density Dependent Factors A limiting factor of a population wherein large, dense populations are more strongly affected than small, less crowded ones. Density Independent Factors limiting factor that affects all populations in similar ways, regardless of population size Type I survivorship Usually experience high survival in early and middle life, followed by a rapid decline in later life. Usually K-selected Type II survivorship Experience roughly a constant mortality rate regardless of age. Prey animals such as birds can follow this pattern of survival. Type III survivorship Experience the greatest mortality early on in life, with relatively low rates of death for those surviving. Usually r-selected. Complementary base pairs Hydrogen bonding between particular pyrimidines and purines. Adenine & Thymine. Cytosine & Guanine. Adenine pairs with Thymine or Uracil Guanine pairs with Cytosine Thymine pairs with Adenine Cytosine pairs with Guanine What does Natural Selection act on phenotypes facilitated diffusion Movement of specific molecules across cell membranes through protein channels active transport Energy-requiring process that moves material across a cell membrane against a concentration difference passive transport Requires NO energy, Movement of molecules from high to low concentration, Moves with the concentration gradient selectively permeable property of biological membranes that allows some substances to pass across it while others cannot; also called semipermeable membrane What does meiosis produce? From a 2n diploid to a 4n haploid What does mitosis produce? Two 2n diploid somatic cells