Question 1 Name the two second messengers that together activate PKC (Protein Ki
ID: 33966 • Letter: Q
Question
Question 1
Name the two second messengers that together activate PKC (Protein Kinase C)
Question 2
___________ are integral membrane proteins of the endoplasmic reticulum that act as lumenal Ca2+ sensors.
A.
SERCAs
B.
STIM proteins
C.
PMCAs
D.
Store-operated calcium channels
E.
IP3 receptors
Question 3
The production of nitric oxide within endothelial cells, and its subsequent detection by neighboring smooth muscle cells, is an example of:
A.
paracrine signaling.
B.
autocrine signaling.
C.
neurotransmission.
D.
endocrine signaling.
E.
long-term signaling.
Question 4
Which of the following is true of rod outer segments in the dark (select any/all answers that apply)?
A.
cGMP-dependent phosphodiesterase activity is upregulated
B.
cGMP-gated sodium channels are closed
C.
GTP is bound to the alpha-subunit of transducin
D.
the photopigments exist in their all-trans isomeric forms
E.
levels of intracellular cGMP are relatively high
Question 5
1.
Both rhodopsin in vision and the muscarinic acetylcholine receptor system in cardiac muscle are coupled to ion channels via G proteins. Describe at least two similarities and two differences between these two systems.
Question 6
Which of the following proteins is an ion channel (select any/all answers that apply)?
A.
the IP3 receptor
B.
TRPV1
C.
the gustatory receptor for "salty"
D.
transducin
E.
the muscarinic receptor
A.
SERCAs
B.
STIM proteins
C.
PMCAs
D.
Store-operated calcium channels
E.
IP3 receptors
Explanation / Answer
Answer 1:
In GPCR pathways, PK-C is activated by DAG and calcium ions. DAG is membrane bound whereas calcium ions come from ER. Together they activate PK-C and activate the signal cascade.
Answer 2: Option A
SERCA is responsible for controlling the movement of calcium ions across the endoplasmic reticulum membrane.
Answer 3: Option A.
Although NO can act as both paracrine as well as autocrine signaling molecule, but here the question is referring to detection by neighbouring cells. So it will be paracrine, because that's what paracrine means- activation or effect on adjacent cells.
Answer 6: TRPV1 / IP3 receptor / Salty gustatory
Muscarinic receptor and transducing are GPCR type, so not an ion channel.
TRPV1 allows the passage of sodium and calcium ions, therefore consisdered as an ion channel. IP3 allows passage of calcium ions across membrane of ER, thus an ion channel. Gustatory "salty" receptors work as ion channels.
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