Question 1

Which of the following best describes the function of restriction enzymes in bacteria?

Accepted Answer

They cut DNA at specific nucleotide sequences for defense against viruses.

Question 2

A restriction enzyme recognizes the sequence $$GAATTC$$ and cuts between the G and A. What is the result of this action?

Accepted Answer

The DNA is cut into fragments with sticky ends.

Question 3

Which of the following is a major point of gene regulation in prokaryotes, as illustrated by the trp operon?

Accepted Answer

Controlling transcription through repressor proteins.

Question 4

The lac operon in E. coli is an example of an inducible operon. Which conditions must be met for its transcription to occur?

Accepted Answer

High lactose and low glucose concentrations.

Question 5

Which equation best represents the relationship between DNA, RNA, and protein in gene expression?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 6

Feedback inhibition in the tryptophan biosynthesis pathway is an example of which type of regulation?

Accepted Answer

Post-translational regulation

Question 7

Which of the following statements about operons is correct?

Accepted Answer

Operons are controlled by a single promoter and transcribed into one mRNA.

Question 8

What is the role of the operator in the trp operon?

Accepted Answer

It is the site where the repressor protein binds to block transcription.

Question 9

Which of the following best explains why cells use only 5-20% of their genes at a time?

Accepted Answer

Gene expression is regulated based on cell type, internal and external conditions.

Question 10

Which of the following is a real-world application of restriction enzymes?

Accepted Answer

Cutting DNA for cloning and genetic engineering.

Question 11

Which of the following is true about the regulation of the lac operon by cAMP and CRP?

Accepted Answer

Low glucose leads to high cAMP and active CRP, stimulating transcription.

Question 12

Which of the following is a characteristic of a repressible operon?

Accepted Answer

It is usually turned ON and can be turned OFF.

Question 13

Which of the following best describes the effect of spending time in nature, according to the American Heart Association?

Accepted Answer

It helps relieve stress and anxiety, improving mood and wellbeing.

Question 14

Which of the following is a correct description of the cell cycle phases?

Accepted Answer

G1, S, G2, M

Question 15

Which of the following is a plausible outcome if a mutation occurs in the operator region of the trp operon?

Accepted Answer

The repressor cannot bind, leading to continuous transcription of trp genes.

Question 16

Which of the following is a multi-step process in eukaryotic gene expression?

Accepted Answer

Transcription, RNA processing, translation

Question 17

Which of the following best describes the function of chaperonin proteins?

Accepted Answer

They assist in the correct folding of newly synthesized polypeptides.

Question 18

Which of the following is true about the MyoD transcription factor?

Accepted Answer

It is only expressed in cells that differentiate as muscle cells.

Question 19

Which of the following best describes the effect of feedback inhibition in the tryptophan biosynthesis pathway?

Accepted Answer

High tryptophan levels inhibit the first enzyme in the pathway, reducing tryptophan synthesis.

Chapter 18 Gene expression

Study Guide - Practice Questions