Receptors Tutorial Flashcards
What do receptors do?
Receptors recognize and respond specifically to signal molecules
What are the 4 types of receptors? (4)
-Endocrine
-Paracrine
-Neuronal
-Contact-Dependant
What distance does endocrine communication act on?
Long distance: a cell signals to cells distributed widely in body
What distance does paracrine communication act on?
Extracellular signal molecules/mediator act locally: cell signals to neighbouring cells
What is an example of paracrine signalling?
Nitric oxide
What distance does neuronal communication act on?
Synapses may occur at long distances from cell bodies-long range communication, but message is delivered quickly and specifically (synapses)
What is a purpose of contact dependent signaling?
The immune system
What are the 4 signaling methods in receptors?
-Ligand-Gated ion channels (ionotropic receptors)
-G protein-coupled receptors
-Kinase-linked receptors
-Nuclear receptors
How long does each of these signalling mechanisms take to send a signal? (4)
-Ligand-Gated ion channels (ionotropic receptors)
-G protein-coupled receptors
-Kinase-linked receptors
-Nuclear receptors
Ligand-Gated ion channels (ionotropic receptors) - milliseconds
G protein-coupled receptors - seconds
Kinase-linked receptors - hours
Nuclear receptors – hours
How many transmembrane domains in an inotropic (Ligand-Gated) receptor?
2-4 transmembrane domains
How many transmembrane domains in GPCRs?
7 transmembrane domains
What do activated G proteins control the function of (follows binding of agonist to GPCR)?
Effectors
What does sympathetic and parasympathetic mean? (2)
Sympathetic– fight or flight
Parasympathetic – rest and digest
Describe signal transduction in heteromeric G proteins?
-Extracellular molecule binds to receptor, GDP exchanged for GTP
-Splits into a subunit and By subunit
-a subunit interacts with target protein so become activated and exchanged GTP for GDP
-By subunit reattaches to a subunit to form G protein
Which enzyme generated 2nd messenger cAMP?
Adenylate Cyclase
