Components of Signal Transduction 4.2.1 Flashcards
What is cellular response?
Responses that are a result of multi-step signal transduction reactions
What are G-proteins?
Specialized proteins with the ability to bind GDP to GTP inside of the cell.
-guanosine diphosphate (GDP)
-guanosine triphosphate (GTP)
What are G protein-coupled receptors (GPCRs)?
-largest family of membrane-bound receptors
consist of an extracellular ligand-binding region and an associated G protein on the cytoplasmic side
What are ion channel receptors?
A type of membrane protein receptor that activates in the presence of certain conditions and subsequently allows the passage of specific ions through a channel in the receptor
-high to low concentration
-different channels will allow the passage of different ions
-under normal condition they are inactive and closed
What is kinase?
An enzyme that catalyzes the transfer of phosphate groups
What is phosphorylation cascade?
A sequential set of phosphorylation reactions that transduces a signal within a signal transduction pathway
(A phosphorylation cascade involves a sequence of phosphorylation and dephosphorization of kinases in a signal transduction pathway.)
What are protein phosphatases?
Enzymes that dephosphorylate proteins by rapidly removing phosphate groups from them
-ends the signal transduction pathway
What is reception?
When a ligand binds to a specific site on a cellular receptor protein (membrane bound protein)
-located on membrane of target cell (or inside the target cell)
-the ligand binding causes the receptor to change its shape and initiate chemicals changes (within the cell)
What are receptor tyrosine kinases?
Membrane-bound receptors with both an intracellular region and an extracellular ligand-binding site
-attach phosphates to tyrosine
-effective when the cell needs to trigger several signal transduction pathways and cellular responses at once
What are relay molecules?
Molecules in the single transduction pathway that transduce the signal along the pathway (through a series of change)
What are second messengers?
Small, hydrophilic, nonprotein molecules or ions that diffuse rapidly throughout the cell in response to the initial signal
-most common second messengers are cyclic AMP and calcium ions
What is signal transduction pathway?
Series of events caused by the binding of a extracellular signaling molecule to a receptor
-receptor triggers first step
-activates other proteins
-similar to falling dominos
What is transduction?
The chemical events that occur after the binding of a ligand and receptor
Passing off a series of chemical changes along relay molecules
-located on the surface of the protein
-results in change to cellular function
What are ligands?
Molecules that selectively bind to larger molecules an alter their shape and functions.
What happens during the response stage in signal transduction?
The synthesis of new proteins by the cell begin
