cell+signaling+review+KEY

Ligand

A molecule that binds specifically to a receptor site of another molecule.

Receptor

A protein that detects a signal molecule and performs an action in response.

Second Messenger

Small molecule with a short half-life that acts as a signaling molecule in the cytoplasm.

Phosphorylation Cascade

The sequential activation of multiple protein kinases that amplifies the signal.

Receptor Tyrosine Kinase (RTK)

Receptor that forms a dimer and autophosphorylates after binding to its ligand.

G Protein

A membrane protein involved in signal transduction; characterized by the binding of GDP or GTP.

G Protein-Coupled Receptor (GPCR)

Receptor that binds its ligand, then activates a G protein.

Ligand-Gated Ion Channel

A channel that allows charged molecules to move through the cell membrane when bound to a ligand.

Kinase

An enzyme that adds a phosphate group to its substrate.

Phosphatase

An enzyme that removes a phosphate group from its substrate.

Phosphorylation

Adding a phosphate to a substrate.

Amplification

Increasing the strength of a biochemical signal, often accomplished through cascades of multiple reactions.

Signal Reception

The initial detection of a signaling molecule by a receptor.

Intracellular Transduction

Chains or cascades of molecules that relay signals inside a cell.

Cellular Response

Changes such as an increase in the transcription of certain genes or the activity of particular enzymes.

Cell Membrane

A cell structure that controls which substances can enter or leave the cell.

Protein in cytosol

Proteins located in the cytosol that can partake in signaling pathways.