1.Which of the following is a cell surface receptor? ( select any/all answers th
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Question
1.Which of the following is a cell surface receptor? (select any/all answers that apply)
A.
Transducin
B.
Ligand-gated ion channel
C.
Receptor serine/threonine kinase
D.
Steroid hormone receptor
E.
Insulin receptor
2.Which of the following can act as an intracellular second messenger (select any/all answers that apply)?
A.
Sodium ions
B.
Potassium ions
C.
Calcium ions
D.
Diacylglycerol
E.
Inositol trisphosphate
3.GEFs:
A.
is another term for GAPs.
B.
accelerate the rate at which GBPs (GTP-binding proteins) hydrolyze their bound GTP.
C.
accelerate the rate at which GBPs exchange GDP for GTP.
D.
phosphorylate substrate molecules.
E.
dephosphorylate substrate molecules.
4. Calmodulin binds calcium ions via:
A.
leucine zipper motifs.
B.
PH domains.
C.
SH2 domains.
D.
PTB domains.
E.
EF hands.
5. Which of the following resides on the intracellular side of the plasma membrane (select any/all answers that apply)?
A.
the N-terminus of a GPCR
B.
the C-terminus of a GPCR
C.
the beta subunit of a heterotrimeric G protein
D.
the G protein-binding domain of a GPCR
E.
the ligand-binding domain of a GPCR
6. An activated GPCR typically functions as a(n) _____________ for its associated heterotrimeric G protein.
A.
GEF
B.
GAP
C.
RGS protein
D.
kinase
E.
phosphatase
7. GTP-binding to the alpha subunit of a heterotrimeric G protein causes (select any/all answers that apply):
A.
the alpha subunit to dissociate from the beta/gamma dimer.
B.
the beta subunit to dissociate from the gamma subunit.
C.
all three G protein subunits to dissociate from one another.
D.
the heterotrimeric G protein to dissociate from the GPCR.
E.
the alpha subunit to dissociate from its effector molecule.
8. IP3 receptors: (select any/all answers that apply)
A.
directly interact with PLC (Phospholipase C) at the plasma membrane.
B.
directly interact with PKC (Protein Kinase C) at the plasma membrane.
C.
are ligand-gated ion channels.
D.
serve as a link between G?q activation and increases in cytosolic calcium.
E.
serve as a link between G?o activation and increases in cytosolic calcium.
9. CaM kinases: (select any/all answers that apply)
A.
are activated by calcium/calmodulin complexes.
B.
are tyrosine kinases.
C.
are serine/threonine kinases.
D.
have a structure similar to PKA.
E.
have a structure similar to PKC.
10. The primary or most proximate event that accounts for light-induced hyperpolarization of photoreceptors is:
A.
the gating of ion channels by retinal.
B.
a rapid fall in the concentration of cGMP, leading to closure of Na+/Ca2+ channels.
C.
a rapid rise in the concentration of cGMP, leading to closure of Na+/Ca2+ channels.
D.
a sudden increase in the concentration of cAMP, leading to activation of potassium channels.
E.
light-induced photoisomerization of calcium channels.
11. A man with a genetic mutation expresses a defective form of the cation channel responsible for the
A.
Transducin
B.
Ligand-gated ion channel
C.
Receptor serine/threonine kinase
D.
Steroid hormone receptor
E.
Insulin receptor
Explanation / Answer
1. B,E
2. C,D,E
3. B
4. A, E
5. C,E
6. A, B, D
7. C,D,A
8. A,D,E
9. B, C,E
10. D
11.
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