Question 1

Which of the following statements best describes the role of the TATA box in eukaryotic transcription initiation?

Accepted Answer

It is a DNA sequence within the core promoter where the TATA-binding protein (TBP) binds, facilitating the assembly of the transcription initiation complex.

Question 2

A researcher discovers a regulatory DNA sequence located thousands of bases downstream from the core promoter of a gene. This sequence increases transcription when bound by specific proteins. What is this sequence most likely called?

Accepted Answer

Enhancer

Question 3

Which of the following mechanisms is NOT a form of post-transcriptional control in eukaryotes?

Accepted Answer

Binding of RNA polymerase to the core promoter

Question 4

In a yeast cell, the presence of galactose leads to increased transcription of five galactose-utilization genes, even though these genes are located on different chromosomes. What is the most likely explanation for this coordinated regulation?

Accepted Answer

All five genes share the same promoter-proximal regulatory sequence that binds a common activator protein.

Question 5

Which statement correctly distinguishes enhancers from promoter-proximal elements?

Accepted Answer

Enhancers can function at considerable distances from the promoter and can be moved or inverted and still function, while promoter-proximal elements are close to the promoter and their position and orientation must be maintained.

Question 6

A mutation in the p53 gene is found in a cancer cell. What is the most direct consequence of this mutation?

Accepted Answer

The cell loses the ability to initiate apoptosis in response to DNA damage, leading to accumulation of mutations.

Question 7

Which of the following is a key difference in gene expression regulation between bacteria and eukaryotes?

Accepted Answer

Eukaryotes rely more heavily on post-transcriptional control mechanisms such as alternative splicing and RNA interference.

Question 8

Which process allows a single gene to produce multiple different proteins in eukaryotic cells?

Accepted Answer

Alternative splicing

Question 9

What is the function of general transcription factors in eukaryotic transcription?

Accepted Answer

They interact with the core promoter and are required for transcription initiation in all cell types.

Question 10

A scientist is studying a gene whose mRNA is rapidly degraded in the cell. Which feature is most likely missing from this mRNA, leading to its instability?

Accepted Answer

A poly(A) tail

Question 11

Which of the following equations best represents the relationship between the number of histone proteins ($$H) $$and the amount of DNA ($$D) $$during S phase, assuming histone synthesis must match DNA replication?

Accepted Answer

$$H = D$$

Question 12

Which of the following is TRUE regarding the function of silencers in eukaryotic gene regulation?

Accepted Answer

Silencers are DNA sequences that repress gene expression when bound by repressor proteins.

Question 13

During stressful conditions such as low oxygen or nutrients, translation in eukaryotic cells is globally shut down. Which protein kinase is inactivated to cause this effect?

Accepted Answer

mTOR

Question 14

Which of the following best explains how transcription factors recognize specific DNA sequences?

Accepted Answer

Transcription factors recognize differences in the composition and shape of DNA bases exposed in the major and minor grooves of the double helix.

Question 15

A cell is able to rapidly respond to new conditions by altering protein activity after translation. Which mechanism is NOT involved in post-translational control?

Accepted Answer

Alternative splicing of mRNA

Question 16

Which of the following statements about proto-oncogenes and tumour suppressors is correct?

Accepted Answer

Proto-oncogenes stimulate cell division and can become oncogenes if mutated; tumour suppressors stop or slow the cell cycle under unfavorable conditions.

Question 17

Which of the following is a direct effect of RNA interference (RNAi) in eukaryotic cells?

Accepted Answer

Destruction or blocking of specific mRNAs, leading to reduced gene expression.

Question 18

A mutation disables the activator protein required for galactose metabolism in yeast. What is the most likely outcome?

Accepted Answer

Transcription of galactose-utilization genes is greatly reduced, even in the presence of galactose.

Question 19

Which of the following best describes the role of the mediator complex in eukaryotic transcription initiation?

Accepted Answer

It integrates the input of many regulatory transcription factors and facilitates the assembly of the transcription initiation complex.

Control of Gene Expression in Eukaryotes: Transcriptional, Post-Transcriptional, and Cancer Genetics

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