Biochemistry Questions and Answers – Principles of Gene Regulation

This set of Biochemistry Multiple Choice Questions & Answers (MCQs) focuses on “Principles of Gene Regulation”.

1. Which of the following is not an example of housekeeping genes?
a) RNA polymerase
b) r-RNA genes
c) Beta galactosidase
d) Enzymes required for basic metabolic pathways common to most cells
View Answer

Answer: c
Explanation: Enzymes required for basic metabolic pathways common to most cells are housekeeping genes; RNA polymerase and r-RNA genes are the examples.

2. Lactose utilization by E. coli requires ____________
a) Lac-Z
b) Lac-A
c) Lac-Y
d) Lac-l
View Answer

Answer: c
Explanation: Lactose utilization by E. coli requires lac-Y.

3. The lactose repressor is encoded by ____________
a) Lac-l
b) Lac-A
c) Lac-Y
d) Lac-Z
View Answer

Answer: a
Explanation: Lac-l encodes lactose repressor.
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4. Where does a repressor bind an operon?
a) Operator
b) Promoter
c) Inducer
d) Catabolite activator site
View Answer

Answer: a
Explanation: Repressor binds an operon at the operator.

5. Lac repressor dissociates from its operator when the repressor binds to ____________
a) Heat shock module
b) Promoter
c) Inducer
d) Catabolite activator site
View Answer

Answer: c
Explanation: The Lac repressor dissociates from its operator when the repressor binds to its inducer, allolactose.
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6. The lac repressor has which of the following DNA-binding motif?
a) Helix-turn-helix
b) Zinc finger
c) Homeodomain
d) Leucine zipper
View Answer

Answer: a
Explanation: The lac repressor has helix-turn-helix DNA-binding motif.

7. Which of the following are the structural motifs that mediate protein-protein interactions?
a) Leucine zipper and basic helix-loop-helix
b) Homeodomain
c) Zinc finger
d) Helix-turn-helix
View Answer

Answer: a
Explanation: Leucine zipper will mediate protein interaction facilitates the dimerization of the protein by interdigitation of two leucine-containing helices on different molecules.
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8. If lactose and glucose are provided in the growth medium of a culture of E. coli ____________
a) Lactose operon is not transcribed
b) Lactose metabolism is favored
c) Both lactose and glucose are metabolized at same rate
d) Adenylate cyclase is activated
View Answer

Answer: a
Explanation: If lactose and glucose are provided in the growth medium of a culture of E. coli lactose operon is not transcribed.

9. Which of the following is not required for the expression of genes in the lactose operon?
a) lacl gene product
b) cAMP
c) Allolactose
d) Adenylate cyclase
View Answer

Answer: a
Explanation: cAMP, allolactose and adenylate cyclase are required for the expression of genes in the lactose operon.
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10. Which out of the following is not an example of an inducible operon?
a) Lactose operon
b) Galactose operon
c) Maltose operon
d) Tryptophan operon
View Answer

Answer: d
Explanation: Lactose operon, galactose operon and maltose operon are examples of the inducible operon.

Sanfoundry Global Education & Learning Series – Biochemistry.

To practice all areas of Biochemistry, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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