Exam IV Review Questions Flashcards
Why aren’t COPII coats used for receptor-mediated endocytosis?
because these coats do not function at the plasma membrane - they work at the ER
Give an example of a hydrophobic ligand.
estrogen
How can neurotransmitters function efficiently when the receptors do not have an extremely high affinity for the neurotransmitter?
Neurotransmitters are released in high concentrations which overcome the poor affinity for the receptors
If I have something that’s secreted and affects nearby cells, what type of signaling am I looking at?
paracrine signaling
If I send out the signal myself and it comes back to me, what type of signaling is that?
autocrine signaling
Relying on diffusion through the bloodstream, what type of signaling is that?
endocrine signaling
Looking at my nerves, what type of signaling is that?
synaptic signaling
Which G-protein subunit binds GTP?
alpha - subunit
What would inhibit CREB phosphorylation (transcription activation)?
- mutated Gs alpha subunit that cannot be bound to GTP
- non-functional adenylyl cyclase
- faulty regulatory subunits of PKA that do not release the catalytic subunits
What is the 2nd step in the activation of RTKs?
receptor autophosphorylation
What is the first step in the activation of RTKs?
ligand binding causing receptor dimerization
What is the 3rd step in the activation of RTKs?
cytosolic proteins bind to phosphorylated tyrosines
What is the 4th step in the activation of RTKs?
intracellular proteins bind to phosphorylated threonines
What change(s) in GAP and GEF proteins might cause a cell to proliferate excessively?
a nonfunctional GAP + a permanently active GEF
