All Flashcards
Define 'signal transduction pathway'.
A series of steps that amplify a small signal into a large cellular response.
What is a 'ligand' in cell signaling?
A signaling molecule that binds to a receptor protein.
Define 'receptor protein'.
A protein on a cell that binds to a ligand, initiating a cellular response.
What is 'phosphorylation'?
The process of adding a phosphate group to a protein, often activating it.
Define 'amplification' in signal transduction.
Making the cellular response bigger or faster, often through a cascade of activation steps.
What are 'secondary messengers'?
Molecules that relay signals from cell surface receptors to target molecules inside the cell, amplifying the signal.
What are the three main steps of cell communication?
- Reception 2. Transduction 3. Response
List the steps of G-protein-coupled receptor (GPCR) activation.
- Ligand binds to GPCR 2. GPCR changes shape, activating a G protein 3. G protein activates adenylyl cyclase 4. Adenylyl cyclase converts ATP to cAMP 5. cAMP activates other molecules, leading to a cellular response.
Describe the process of signal transduction.
A ligand binds to a receptor, triggering a cascade of intracellular events (phosphorylation, activation of secondary messengers) that amplify the signal and lead to a cellular response.
What is the effect of a ligand binding to a receptor protein?
The receptor protein changes shape, initiating a signal transduction pathway.
What is the effect of phosphorylation of a protein?
The protein is often activated, leading to a cellular response.
What is the effect of activating adenylyl cyclase?
Adenylyl cyclase converts ATP to cAMP, a secondary messenger.
What is the effect of cAMP activation?
cAMP activates protein kinases, leading to further phosphorylation and a cellular response.
What is the effect of lipid hormones binding to intracellular receptors?
Production of transcription factors, leading to new protein synthesis and a longer-lasting cellular response.