cell signaling ii

Question 1

where are GPCRs synthesized
in the cell?

Answer 1

the ER

Question 2

True or False: Gα has intrinsic kinase activity.

Answer 2

false it has GTPase activity

Question 3

True or False: Binding of acetylcholine to its
GPCR on heart pacemaker cells triggers the
dissociation of the Gβγ subunit from the G
protein. The Gβγ subunit then directly activates
K+ channels, leading to depolarization of the
membrane and a slower heart rate.

Answer 3

true

Question 4

Which of the following events normally activates a GTP-binding protein?
A. GTP hydrolysis by protein
B. Activation by an upstream GTPase-activating protein
C. Activation by an upstream guanine nucleotide exchange factor
D. Phosphorylation of a bound GDP molecule by an upstream phosphorylase
E. Pi release after GTP hydrolysis

Answer 4

C. Activation by an upstream guanine nucleotide exchange factor