AP Biology Unit 4 Progress Check MCQ Review

This set of vocabulary flashcards covers key concepts from the AP Biology Unit 4 MCQ transcript, focusing on cell signaling, metabolic regulation, feedback loops, and the eukaryotic cell cycle.

Ligand

A chemical messenger that first binds to a receptor, which then changes shape to initiate a signaling pathway.

Second messenger

A molecule that relays messages from receptors to other molecules only inside the cell.

Kinases

A type of enzyme that activates proteins by transferring a phosphate group from $ATP$ to protein substrates.

Epinephrine

A hormone released into the circulatory system during a fight-or-flight response which requires a specific receptor to trigger a cellular response.

SRY gene

A gene found on the Y chromosome that triggers the male sexual development pathway in mammals; if absent or nonfunctional, the embryo will exhibit female sexual development.

CED-9

A gene in Caenorhabditis elegans that acts as a regulator to inhibit apoptosis in the absence of a signal promoting it.

CED-3 and CED-4

Genes discovered in the nematode worm Caenorhabditis elegans that were found to promote apoptosis (programmed cell death).

Insulin receptor

A transmembrane protein with an extracellular domain that binds to the peptide hormone insulin and an intracellular domain that stimulates a signal transduction pathway.

GLUT4

A glucose transport protein stored in vesicles inside the cell that is translocated to the plasma membrane upon stimulation of the insulin signaling pathway.

Beta-2 adrenergic receptor

A membrane-bound protein that binds to epinephrine to trigger a signaling cascade that stimulates glycogen breakdown and inhibits glycogen synthesis.

Fibroblast growth factor receptors (FGFR)

Transmembrane proteins that regulate cell proliferation and differentiation via intracellular protein kinase domains.

Phosphofructokinase (PFK)

A key enzyme in glycolysis for which $ATP$ acts as both a substrate and an allosteric regulator.

Negative feedback regulation

A process, such as that involving $ATP$ and $PFK$, where a reaction is inhibited when a product or regulator binds to an allosteric site and changes the shape of the active site.

Insulin

A hormone that acts to lower the blood glucose level by stimulating cells to take in excess glucose.

Glucagon

A hormone involved in regulating blood glucose levels that acts to increase the blood glucose level.

Vitamin K

A nutrient required for the formation of the active form of several clotting factors, including Factor $X$.

Warfarin

A drug used to treat blood clots by blocking the formation of the active form of vitamin $K$-dependent clotting factors.

S phase

The phase of the cell cycle during which DNA replication occurs, resulting in the doubling of genetic information.

Mitosis

The stage of the cell cycle where replicated $DNA$ is condensed into chromosomes and passed on to two genetically identical daughter cells.

Interphase

The portion of the cell cycle where cells spend the majority of their time preparing for division and replicating genetic material.

EGFR (Epidermal growth factor receptor)

A cell surface receptor that, when activated by a growth factor, triggers a signal transduction pathway leading to increased frequency of cell division.

p53

A tumor suppressor protein that binds to DNA and activates target genes like $p21$ and $BAX$ to regulate cell-cycle arrest and apoptosis.

p21

A protein that promotes cell-cycle arrest; its synthesis is activated by the tumor suppressor protein $p53$.

BAX

A protein that promotes apoptosis (programmed cell death); its synthesis is activated by the tumor suppressor protein $p53$.

G1/S checkpoint

A regulatory point in the cell cycle that may halt progression if there are not enough nucleotides available to construct new $DNA$.