Question 1

Which of the following is NOT a stage at which gene expression can be regulated in eukaryotic cells?

Accepted Answer

DNA replication control

Question 2

In the lac operon, what is the role of lactose in gene regulation?

Accepted Answer

It is the inducer molecule.

Question 3

Which molecule binds to the operator of the trp operon to block transcription when tryptophan is present?

Accepted Answer

Active repressor-tryptophan complex

Question 4

What is the effect of histone acetylation on chromatin structure and gene expression?

Accepted Answer

It decreases chromatin packing, increasing transcription.

Question 5

Which nucleotide is methylated during DNA methylation that represses transcription?

Accepted Answer

Cytosine

Question 6

A mutation in the trp regulatory gene prevents the repressor from binding tryptophan. What is the result?

Accepted Answer

The trp operon will be expressed continuously.

Question 7

Which of the following best describes the function of an enhancer in eukaryotic gene regulation?

Accepted Answer

It is a DNA sequence that increases transcription by binding specific transcription factors.

Question 8

Which of the following is TRUE regarding the lac operon in E. coli?

Accepted Answer

The lac operon is an inducible operon that is normally turned off.

Question 9

What is the effect of high glucose and low lactose levels on the expression of the lac operon?

Accepted Answer

The lac operon is not expressed.

Question 10

Which of the following is a multi-step problem: If a cell has high levels of glucose and low levels of cAMP, what will happen to the lac operon?

Accepted Answer

It will not be expressed because cAMP is required for activation.

Question 11

Which of the following statements about alternative RNA splicing is correct?

Accepted Answer

It allows a single gene to produce multiple protein variants.

Question 12

Which process involves the addition of a methyl group to cytosine nucleotides, leading to transcriptional repression?

Accepted Answer

DNA methylation

Question 13

What is the function of ubiquitin in eukaryotic cells?

Accepted Answer

It tags proteins for degradation by proteasomes.

Question 14

Which of the following is a correct description of a repressible operon?

Accepted Answer

It is normally turned on and can be turned off by a corepressor.

Question 15

Which of the following is NOT a function of post-translational modification of proteins?

Accepted Answer

Protein splicing

Question 16

Which of the following statements about siRNA is TRUE?

Accepted Answer

siRNA binds to mRNA and leads to its degradation.

Question 17

Which of the following is a real-world application of gene regulation in medicine?

Accepted Answer

Using siRNA to silence disease-causing genes in gene therapy.

Question 18

Which equation best represents the relationship between cAMP levels and lac operon activation?

Accepted Answer

$$cAMP ightarrow CRP ightarrow 	ext{lac operon activation}$$

Question 19

Which of the following is a consequence of DNA methylation in eukaryotic cells?

Accepted Answer

Decreased transcription of the gene

Question 20

Which of the following is a correct statement about general transcription factors in eukaryotes?

Accepted Answer

They are required for transcription of all protein-coding genes.

Regulation of Gene Expression (Ch. 18): Prokaryotic and Eukaryotic Mechanisms

Study Guide - Practice Questions