Q: Which equation best represents the process of mRNA degradation control?

$$\text{mRNA} \xrightarrow{\text{degradation}} \text{inactive mRNA}$$

Question 1

Which of the following best describes the function of transcriptional regulators in eukaryotic gene expression?

Accepted Answer

They recognize and bind to regulatory DNA sequences to control transcription initiation.

Question 2

In the lac operon, what happens when lactose is present and glucose is absent?

Accepted Answer

The CAP protein binds to the CAP site, enhancing transcription of lac genes.

Question 3

Which step in gene expression is regulated by microRNAs (miRNAs)?

Accepted Answer

Translation and mRNA stability control

Question 4

A mutation prevents the methylation of cytosine residues in DNA. What is the most likely consequence for gene expression?

Accepted Answer

Genes may be abnormally expressed due to loss of epigenetic regulation.

Question 5

Which equation best represents the process of mRNA degradation control?

Accepted Answer

$$	ext{mRNA} \xrightarrow{	ext{degradation}} 	ext{inactive mRNA}$$

Question 6

Which of the following is a real-world example of post-transcriptional control?

Accepted Answer

Alternative splicing of the human dystrophin gene, leading to different protein isoforms.

Question 7

If a cell is infected with a virus that produces double-stranded RNA, which mechanism will most likely be activated?

Accepted Answer

RNA interference (RNAi) will degrade the foreign RNA.

Question 8

Which of the following statements about operons is correct?

Accepted Answer

Operons allow bacteria to regulate clusters of genes under a single promoter.

Question 9

A cell receives a transient signal that activates the expression of protein A, which is normally required for its own transcription. What is the most likely outcome?

Accepted Answer

Protein A expression will be maintained in all cell descendants due to positive feedback.

Question 10

Which of the following best describes the role of general transcription factors in eukaryotic transcription?

Accepted Answer

They assemble at the promoter to help RNA polymerase initiate transcription.

Question 11

Which equation best represents the process of translation control?

Accepted Answer

$$	ext{mRNA} \xrightarrow{	ext{translation}} 	ext{protein}$$

Question 12

Which of the following is a plausible consequence of defective reader-writer complexes in histone modification?

Accepted Answer

Parental pattern of histone modification will not be re-established in daughter cells.

Question 13

Which scenario would most likely result in the lac operon being strongly expressed?

Accepted Answer

Low glucose, lactose available

Question 14

Which of the following is NOT a post-transcriptional control mechanism?

Accepted Answer

DNA methylation

Question 15

Which equation best represents the process of protein activity control?

Accepted Answer

$$	ext{protein} \xrightarrow{	ext{modification}} 	ext{inactive protein}$$

Question 16

Which of the following is a direct result of DNA methylation?

Accepted Answer

Reduced transcription of methylated genes

Question 17

Which of the following best explains why the lac operon is rarely found in eukaryotes?

Accepted Answer

Eukaryotic genes are usually regulated individually, not in clusters.

Question 18

Which of the following is a plausible effect of a mutation in the TATA box of a eukaryotic gene?

Accepted Answer

RNA polymerase will fail to initiate transcription efficiently.

Question 19

Which of the following is a function of the mediator complex in eukaryotic transcription?

Accepted Answer

It facilitates communication between transcriptional regulators and RNA polymerase II.

Question 20

Which of the following best describes the role of Dicer in RNA interference?

Accepted Answer

It cuts double-stranded RNA into short fragments called siRNAs.

Control of Gene Expression: Mechanisms and Regulation

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