AP®︎ Biology: Unit 4 Flashcards
Master key terms and definitions for Unit 4 of AP Biology – Cell Communication and Cell Cycle to help you prep for quizzes and the AP exam.
Cell Communication
The process by which cells detect, send, and respond to information.
The process by which cells detect, send, and respond to information.
Communication that occurs when neighboring cells physically touch and exchange information.
Communication in which cells release signaling molecules that bind to target cells.
Nearby targets respond to local regulators; distant targets respond to signals carried farther, often in blood.
Short-range signaling molecules that affect cells close to the releasing cell.
Immune cells that display antigen fragments on their surface to activate other immune cells.
Immune cells that recognize presented antigens and coordinate other parts of the immune response.
Immune cells that directly contact and destroy infected or abnormal body cells.
Chemical messengers released by neurons that signal across short distances to nearby cells.
Chemical signaling by plant cells that alerts nearby cells to pathogens or herbivore attack.
Local signaling molecules that form concentration gradients and guide embryonic development.
A hormone that promotes glucose uptake by body cells and lowers blood sugar.
A hormone that stimulates growth, cell division, and protein synthesis in target tissues.
Hormones that regulate metabolic rate, growth, and development throughout the body.
Sex hormones that regulate reproductive development, function, and secondary sex characteristics.
A protein that binds a specific signal and initiates a cellular change.
The receptor region that specifically recognizes and binds a particular chemical messenger.
Membrane receptors bind external signals; intracellular receptors bind signals inside the cell.
A shape change in a receptor that starts intracellular signaling after ligand binding.
Seven-pass membrane receptors that activate G proteins to relay external signals inward.
A sequence of protein activations caused by adding phosphate groups at each step.
One signaling event activates many molecules, producing a much larger cellular effect.
Small intracellular molecules that relay and amplify signals from activated receptors.
A common second messenger that activates intracellular proteins and amplifies signaling.
Membrane channels that open or close when a signaling molecule binds.
A series of reception, transduction, and response steps linking a signal to cellular change.
Chemical signaling molecules released by one cell type that travel long distances, often through the bloodstream, to target cells.
A signaling molecule that binds specifically to a receptor protein and initiates a cellular response.
Conversion of an external signal into specific intracellular responses through a signaling pathway.
A hormone signal that triggers liver cells to convert glycogen into glucose.
Signaling proteins that regulate gene expression, cell replication, and immune cell division.
Chemical signals that bind receptors and activate genes required for yeast mating.
A plant hormone gas that triggers enzyme production and fruit ripening responses.
Developmental regulatory genes that specify body regions and organize animal body plans.
Changes in receptors or pathway proteins can weaken, block, or overactivate downstream responses.
Specific structural regions whose alteration can change ligand binding or signal transmission.
Molecules that bind pathway components and either stimulate or block signal transduction.
Detection of a signaling molecule when it binds to a specific receptor protein.
Bacterial or microbial communication using secreted signaling molecules to detect population density and coordinate gene expression and behavior.
Cell signaling can produce responses such as changes in gene expression, enzyme activity, metabolism, secretion, movement, cell growth, phenotype, or programmed cell death.
Maintenance of a relatively stable internal environment despite internal or external changes.
Regulatory loops in which a system's output influences its own activity.
A response that counteracts a change and returns conditions toward a set point.
A response that amplifies a change and moves conditions farther from a set point.
The target value or normal range a regulated condition tends to return to.
Insulin lowers blood sugar by promoting storage; glucagon raises it by stimulating glycogen breakdown.
Cervical stretching triggers oxytocin release, which intensifies contractions until birth ends the loop.
A hormone that stimulates uterine contractions and milk release during positive feedback responses.
Suckling stimulates hormone release, increasing milk production and release until nursing stops.
Ethylene from ripening fruit stimulates nearby fruits to ripen and release more ethylene.
Regulation occurs through molecule interactions, cell responses, and coordinated whole-body system changes.
Pancreatic hormones that lower or raise blood glucose to maintain homeostasis.
A disorder in which insulin production or response fails, disrupting blood glucose homeostasis.
One amplifies change, while the other reverses change to restore a set point.
Highly regulated sequence of growth, DNA replication, and division in eukaryotic cells.
Identical DNA copies joined at a centromere after replication during S phase.
Nuclear division that produces two genetically identical daughter cells with complete genomes.
Enables growth, tissue repair, and asexual reproduction in eukaryotic organisms.
Microtubule structure that attaches to chromosomes and moves them during mitosis.
Protein structures on centromeres where spindle fibers attach to move chromatids.
Division of the cytoplasm that produces two separate daughter cells after mitosis.
Microtubule-organizing structures that replicate before mitosis and move to opposite poles.
Uncondensed DNA-protein complex present during interphase and replicated in S phase.
G1, S, and G2 make up the stage when cells grow, replicate DNA, and prepare for division.
Prophase condenses chromosomes, metaphase aligns them, anaphase separates chromatids, and telophase reforms nuclei.
Animal cells form a cleavage furrow, while plant cells build a cell plate.
Internal control points that stop or allow progression only when key conditions are met.
G1 checks size, nutrients, signals, and DNA; G2 checks replication and damage; M checks spindle attachment.
Regulatory proteins where cyclins activate CDKs to drive cell cycle transitions.
Cyclin levels fluctuate, while CDK levels stay relatively constant and work only when activated.
Uncontrolled cell division caused by failed regulation and checkpoint bypass.
Programmed cell death that eliminates cells that are damaged, unnecessary, or beyond repair, often in response to specific signals.
A resting, nondividing state entered when cells exit the cell cycle or pause, often after G1, until receiving appropriate signals.
