Question 1

Which of the following best describes the role of histone acetylation in gene expression regulation?

Accepted Answer

Histone acetylation relaxes chromatin structure, increasing accessibility of DNA for transcription.

Question 2

A researcher discovers a mutation that prevents the addition of methyl groups to cytosine bases in DNA. What is the most likely effect of this mutation on gene expression?

Accepted Answer

Gene expression will increase because methylation usually represses transcription.

Question 3

Which equation correctly represents the process by which RNA is synthesized from a DNA template?

Accepted Answer

$$DNA \rightarrow RNA$$

Question 4

In eukaryotic cells, which of the following is a direct consequence of alternative splicing?

Accepted Answer

Multiple proteins can be produced from a single gene.

Question 5

Which of the following statements about microRNAs (miRNAs) is correct?

Accepted Answer

miRNAs bind to complementary sequences on mRNA to block translation or degrade the mRNA.

Question 6

A cell is exposed to a signal that activates a transcription factor, which then binds to an enhancer region. What is the most likely outcome?

Accepted Answer

The transcription factor will increase gene expression by facilitating RNA polymerase binding.

Question 7

Which of the following best explains why different cell types in a multicellular organism can have different functions despite having the same DNA?

Accepted Answer

Different cell types express different sets of genes due to differential gene regulation.

Question 8

Which process is most directly responsible for the removal of introns from pre-mRNA in eukaryotic cells?

Accepted Answer

Splicing

Question 9

A mutation causes a protein to be tagged with ubiquitin. What is the most likely fate of this protein?

Accepted Answer

It will be degraded by the proteasome.

Question 10

Which of the following is a post-transcriptional mechanism for regulating gene expression?

Accepted Answer

RNA splicing

Question 11

Which of the following best describes the function of a promoter in gene expression?

Accepted Answer

A promoter is a DNA sequence where RNA polymerase binds to initiate transcription.

Question 12

Which of the following equations correctly represents the central dogma of molecular biology?

Accepted Answer

$$DNA \rightarrow RNA \rightarrow Protein$$

Question 13

A scientist is studying a gene that is only expressed in liver cells but not in skin cells. Which of the following mechanisms is most likely responsible for this tissue-specific expression?

Accepted Answer

Liver cells have specific transcription factors that activate the gene.

Question 14

Which of the following statements about enhancers is correct?

Accepted Answer

Enhancers are DNA sequences that increase the rate of transcription when bound by activator proteins.

Question 15

Which of the following is a consequence of gene duplication in evolution?

Accepted Answer

Gene duplication allows for the evolution of new gene functions.

Question 16

A patient has a mutation in the TATA box of a gene's promoter. What is the most likely effect on gene expression?

Accepted Answer

Transcription initiation will be impaired, reducing gene expression.

Question 17

Which of the following best explains the role of transcription factors in gene regulation?

Accepted Answer

Transcription factors bind to specific DNA sequences to increase or decrease transcription of target genes.

Question 18

Which of the following mechanisms allows a single gene to produce multiple protein isoforms?

Accepted Answer

Alternative splicing

Question 19

A scientist observes that a gene is highly expressed in response to a specific hormone. Which regulatory element is most likely involved in this process?

Accepted Answer

A hormone-responsive enhancer

Question 20

Which of the following is a function of small interfering RNAs (siRNAs) in gene regulation?

Accepted Answer

siRNAs bind to mRNA and promote its degradation, silencing gene expression.

Regulation of Gene Expression in Eukaryotes and Prokaryotes

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