Explore topic-wise MCQs in Biochemistry.

This section includes 18 Mcqs, each offering curated multiple-choice questions to sharpen your Biochemistry knowledge and support exam preparation. Choose a topic below to get started.

1.

Ras protein is a ____________

A. G-protein switch
B. Small monomeric GTPase switch protein
C. Serine-threonine kinase
D. Tyrosine kinase
Answer» C. Serine-threonine kinase
Discussion
2.

Which of the following is a short-lived messenger that acts by stimulating a soluble guanylyl cyclase, raising [cGMP] and stimulating PKG?

A. NO
B. NO2
C. NO3–
D. N2O
Answer» B. NO2
Discussion
3.

Which of the following is not responsible of producing diarrhea?

A. Elevation in [cGMP]
B. Increase in Cl– secretion
C. Decrease in reabsorption of water by the intestinal epithelium
D. Decrease in Cl– secretion
Answer» E.
Discussion
4.

cGMP-dependent protein kinase is also called ____________

A. Protein kinase B
B. Protein kinase A
C. Protein kinase G
D. Protein kinase C
Answer» D. Protein kinase C
Discussion
5.

Activation of guanylyl cyclase produces ____________

A. Guanosine 3’, 5’-cyclic monophosphate
B. Guanosine 2’, 5’-cyclic monophosphate
C. Guanosine 4’, 5’-cyclic monophosphate
D. Guanosine 1’, 5’-cyclic monophosphate
Answer» B. Guanosine 2’, 5’-cyclic monophosphate
Discussion
6.

Protein kinase ERK is activated by phosphorylation of ____________

A. Only Thr
B. Only Tyr
C. Both Thr and Tyr
D. Only Ser
Answer» D. Only Ser
Discussion
7.

The enzyme activated by cyclic AMP, passing on the hormonal signal is ____________

A. Protein kinase B
B. Protein kinase A
C. Protein kinase C
D. G protein receptor kinase
Answer» C. Protein kinase C
Discussion
8.

cAMP and cGMP are derived from ____________

A. ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively
B. ATP and GTP by the actions of adenylate cyclase and gualnlate cyclase respectively
C. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
D. None of the mentioned
Answer» C. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
Discussion
9.

SH2 domain specifically binds to _____________

A. GDP
B. Ca+2
C. Phosphorylated tyrosine residues
D. Phosphorylated serine residues
Answer» D. Phosphorylated serine residues
Discussion
10.

WHICH_OF_THE_FOLLOWING_IS_A_SHORT-LIVED_MESSENGER_THAT_ACTS_BY_STIMULATING_A_SOLUBLE_GUANYLYL_CYCLASE,_RAISING_[CGMP]_AND_STIMULATING_PKG??$

A. NO
B. NO<sub>2</sub>
C. NO<sub>3</sub><sup>–</sup>
D. N<sub>2</sub>O
Answer» B. NO<sub>2</sub>
Discussion
11.

Ras protein is a$

A. G-protein switch
B. Small monomeric GTPase switch protein
C. Serine-threonine kinase
D. Tyrosine kinase
Answer» C. Serine-threonine kinase
Discussion
12.

cGMP-dependent protein kinase is also called

A. Protein kinase B
B. Protein kinase A
C. Protein kinase G
D. Protein kinase C
Answer» D. Protein kinase C
Discussion
13.

Activation of guanylyl cyclase produces

A. Guanosine 3’, 5’-cyclic monophosphate
B. Guanosine 2’, 5’-cyclic monophosphate
C. Guanosine 4’, 5’-cyclic monophosphate
D. Guanosine 1’, 5’-cyclic monophosphate
Answer» B. Guanosine 2‚Äö√Ñ√∂‚àö√ë‚àö¬•, 5‚Äö√Ñ√∂‚àö√ë‚àö¬•-cyclic monophosphate
Discussion
14.

Protein kinase ERK is activated by phosphorylation of

A. Only Thr
B. Only Tyr
C. Both Thr and Tyr
D. Only Ser
Answer» D. Only Ser
Discussion
15.

The enzyme activated by cyclic AMP, passing on the hormonal signal is

A. Protein kinase B
B. Protein kinase A
C. Protein kinase C
D. G protein receptor kinase
Answer» C. Protein kinase C
Discussion
16.

Which of the following is false about phosphorylation by IRS on serine residue?

A. It is an inhibitory phosphorylation
B. It is molecular mechanism for insulin resistance
C. It increases insulin levels
D. Target tissues fail to respond to circulating insulin
Answer» D. Target tissues fail to respond to circulating insulin
Discussion
17.

cAMP and cGMP are derived from

A. ATP and GTP by the actions of guanylate cyclase and adenylate cyclase respectively
B. ATP and GTP by the actions of adenylate cyclase and gualnlate cyclase respectively
C. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
D. None
Answer» C. GTP and ATP by the actions of adenylate cyclase and guanylate cyclase respectively
Discussion
18.

SH2 domain specifically binds to

A. GDP
B. Ca<sup>+2</sup>
C. Phosphorylated tyrosine residues
D. Phosphorylated serine residues
Answer» D. Phosphorylated serine residues
Discussion