Cell Signaling Vocabulary

This is a collection of flashcards covering key vocabulary terms related to cell signaling, signal transduction, and related concepts.

Cell signalling

The molecular mechanisms by which cells detect and respond to external stimuli and send messages to other cells.

Signal transduction

Conversion of an impulse or stimulus from one physical or chemical form to another.

Hormone

Extracellular signal molecule that is secreted and transported via the bloodstream (in animals) or the sap (in plants) to target tissues on which it exerts a specific effect.

Neurotransmitter

Small signalling molecule secreted by a nerve cell at a synapse to transmit information to a postsynaptic (target) cell.

Largest Class of Extracellular Signal Molecules

Molecules that are too large or hydrophilic to cross the plasma membrane of the target cell; they bind to cell surface receptor proteins.

Small/Hydrophobic Extracellular Signal Molecules

Molecules that are small enough or hydrophobic enough to pass through the plasma membrane and into the cytosol of the target cell, where they bind to intracellular receptor proteins.

Cell-Surface Receptors Function

Detect a signal on the outside of the cell and relay it across the membrane to the inside of the cells.

Intracellular signalling pathways perform crucial cell functions

Relay, amplify, integrate, distribute, and engage in feedback regarding a signal.

Molecular switches

On/off switches in signalling pathways; receipt of a signal causes them to switch from an inactive (off) to active (on) state.

Ion-channel-coupled receptors

Receptor that opens in response to the binding of an extracellular signal molecule, allowing a specific ion through the plasma membrane, altering the membrane potential and potentially producing an electrical current.

G-protein-coupled receptors (GPCRs)

Receptor that, when bound by an extracellular signal molecule, interacts with a trimeric G protein on the cytosolic side of the plasma membrane, activating or deactivating an enzyme or ion channel in the membrane.

Enzyme-coupled receptors

Receptors that either act as enzymes themselves or associate with enzymes inside the cell when a signal molecule binds.