Question 1

Which of the following best describes the role of an enhancer in eukaryotic gene expression?

Accepted Answer

An enhancer is a DNA sequence that increases transcription when bound by an activator, and can function at a distance from the promoter.

Question 2

A mutation deletes the TATA box from the core promoter of a gene. What is the most likely effect on transcription?

Accepted Answer

Transcription will be severely reduced or abolished because the TATA box is essential for accurate initiation.

Question 3

Which experimental approach would best quantify the effect of a promoter mutation on gene expression?

Accepted Answer

Reporter gene assay measuring mRNA levels using RT-qPCR.

Question 4

In the yeast GAL gene system, what is the role of GAL80 in the absence of galactose?

Accepted Answer

GAL80 acts as a repressor by binding to GAL4 and blocking its activation domain.

Question 5

A yeast mutant continuously expresses GAL genes regardless of galactose presence. Which gene is most likely mutated?

Accepted Answer

GAL80

Question 6

Which of the following statements about insulators is correct?

Accepted Answer

Insulators block the action of an enhancer on a non-target gene when located between the enhancer and the promoter.

Question 7

If deletion of a control element causes an increase in reporter gene expression, what is the normal role of that control element?

Accepted Answer

To repress gene expression.

Question 8

Which of the following best explains why lens cells express crystallin but not albumin, while liver cells express albumin but not crystallin?

Accepted Answer

Different specific transcription factors are made in each cell type, determining which genes are expressed.

Question 9

Which of the following is a cis-acting regulatory element?

Accepted Answer

Enhancer

Question 10

A deletion removes one of the four UASG sites upstream of GAL1 in yeast. What is the most likely effect on GAL1 transcription in the presence of galactose?

Accepted Answer

Transcription will be reduced but not eliminated.

Question 11

Which of the following best describes combinatorial control of gene activation?

Accepted Answer

Multiple transcription factors interact with various control elements to regulate gene expression.

Question 12

Which of the following experimental results would indicate that a deleted promoter region contains essential sequences for basal transcription?

Accepted Answer

Transcription is abolished in both nuclear extract and purified systems.

Question 13

Which of the following is a trans-acting factor in eukaryotic gene regulation?

Accepted Answer

Transcription factor

Question 14

Which of the following best describes the effect of DNA looping in eukaryotic transcription regulation?

Accepted Answer

It brings distant regulatory elements such as enhancers and silencers into proximity with the promoter, facilitating or inhibiting transcription.

Question 15

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

Accepted Answer

DNA replication fidelity

Question 16

A mutation in the GAL4 gene removes the region encoding amino acids 1 to 100. What is the most likely effect on GAL1 transcription in the presence of galactose?

Accepted Answer

Transcription will be reduced or abolished because the DNA-binding domain is missing.

Question 17

Which of the following best explains why the undeleted promoter template produces high transcription in nuclear extract but low transcription in a purified system?

Accepted Answer

The purified system lacks specific transcription factors present in the nuclear extract that are required for high transcription.

Question 18

Which of the following is a correct statement about the function of silencers?

Accepted Answer

Silencers are DNA sequences that repress or decrease the level of transcription initiation when bound by repressors.

Question 19

Which of the following is a real-world application of reporter gene assays in genetics research?

Accepted Answer

Identifying which DNA regulatory elements are necessary for tissue-specific gene expression by measuring GFP fluorescence in transgenic mice.

Eukaryotic Gene Expression and Regulation: Structured Study Notes

Study Guide - Practice Questions

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