Questions and answers for exam Preparation

MCQs

Total Questions : 121 | Page 8 of 13 pages

Question 71. A cell is known to respond to a particular signaling molecule. Which of the following must be true of this cell?

It contains the receptor for the signaling molecule
It is also the site of production for the signaling molecule
It is in the heart muscle
It is incapable of signal transduction

Discuss Question

Answer: Option A. -> It contains the receptor for the signaling molecule

Question 72. In the signal transduction mechanism known as protein phosphorylation

the signaling molecule binds to a surface receptor
phosphorylated proteins act with enzymes to trigger the signal cascade
All of these
receptor kinases play a key role in triggering the signal cascade

Discuss Question

Answer: Option C. -> All of these

Question 73. In vasodilation, proper nerve signals sent to blood vessels cause

reduced blood pressure
relaxation of smooth muscle cells
the release of nitric oxide from endothelial cells
All of these

Discuss Question

Answer: Option D. -> All of these

Question 74. What is the name of the protein signaling molecule that alters glucose uptake, and where would its receptors be located?

NGF; the nerves involved in simple reflexes
Insulin; many different cell types that use glucose for fuel
Insulin; beta cells of the pancreas
PDGF; the blood

Discuss Question

Answer: Option B. -> Insulin; many different cell types that use glucose for fuel

Question 75. Cell signaling can be classified into

three distinct types based on the signaling molecules
two distinct types based on the distance over which the signaling molecules act
None of these
three distinct types based on the distance over which the signaling molecules act

Discuss Question

Answer: Option D. -> three distinct types based on the distance over which the signaling molecules act

Question 76. The enzyme that catalyzes the splitting of PIP2 into two molecules of inositol triphosphate (IP3) and diacylglycerol in cell signaling, is

phospholipase C
phosphokinase C
phosphodiesterase C
lipokinase

Discuss Question

Answer: Option A. -> phospholipase C

Question 77. A signal cascade induced by adrenaline or thyroxine

must begin with receipt of the signal molecule by a surface receptor
results in the activation of a sequence of enzymes needed for the cell effect
All of these
involves the activation of a G protein

Discuss Question

Answer: Option C. -> All of these

Question 78. Which of the following processes involve the combining of a message from one signaling molecule with that of another to either enhance or inhibit a cellular effect?

Signal transduction
Signal integration
Signal reception
Signal amplification

Discuss Question

Answer: Option B. -> Signal integration

Question 79. Which of the following is a second messenger?

Both (a) and (b)
Diacyl glycerol
lnositol 1,4,5-triphosphate
Phospholipase C

Discuss Question

Answer: Option A. -> Both (a) and (b)

Question 80. The binding of ligands to many G-proteins linked receptors leads to shortlived

increase in the concentration of certain intracellular signaling molecules called second messenger
decrease in the concentration of certain intracellular signaling molecules called second messenger
decrease in the concentration of certain extracellular signaling molecules called first messenger
increase in the concentration of certain extracellular signaling molecules called first messenger

Discuss Question

Answer: Option A. -> increase in the concentration of certain intracellular signaling molecules called second messenger