All Flashcards
Compare cell surface receptors and intracellular receptors.
Cell surface receptors: Located on the plasma membrane, bind to hydrophilic ligands. | Intracellular receptors: Located inside the cell, bind to hydrophobic ligands that can cross the membrane.
Differentiate between primary and secondary messengers.
Primary messenger: The initial signaling molecule (ligand) that binds to the receptor. | Secondary messenger: Small, non-protein molecules that relay and amplify the signal inside the cell.
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.
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.