Morris, Biology for the AP Course 1e - Mod 21

signal transduction

The process by which an external signal is converted to an internal response.

amplification

The process in which a small number of signaling molecules can generate a very large response.

G protein-coupled receptor

A receptor protein in cell membranes that is associated with a G protein that in turn alters activity of adenylyl cyclase and other generators of second messengers in responding cells.

second messenger

An intermediate signaling molecule that amplifies a response inside a cell.

cyclic adenosine monophosphate (cAMP)

Derived from ATP and serves as an intracellular second messenger in many signal transduction pathways.

kinase

An enzyme that catalyzes the transfer of a phosphate group from ATP to another molecule.

signaling cascade

A series of chemical reactions inside of a cell that are initiated by a signal and are typically amplified to produce a large cellular response.

receptor-protein kinase

A receptor protein in cell membranes that have kinase activity that is activated after binding to an extracellular
signaling molecule.

ligand-gated channel

Receptor proteins in cell membranes that alter membrane permeability to ions after binding to an extracellular hydrophilic signaling molecule.

gene expression

The production of a functional gene product, such as a protein; the "turning on" of a gene.