Question 1

Which of the following best describes the effect of DNA methylation at CpG islands near a gene promoter?

Accepted Answer

It inhibits transcription by preventing transcription factors from binding to the promoter.

Question 2

What is the primary role of histone acetylation in gene regulation?

Accepted Answer

It reduces the affinity of DNA for histones, making promoter regions more accessible for transcription.

Question 3

A mutation causes a specific transcription factor to be nonfunctional in liver cells. Which of the following is the most likely consequence?

Accepted Answer

Only genes requiring that specific transcription factor for activation will be affected.

Question 4

Which of the following best explains the concept of combinatorial control in eukaryotic gene regulation?

Accepted Answer

Multiple regulatory proteins interact with control elements to determine gene expression.

Question 5

Alternative RNA splicing allows a single gene to:

Accepted Answer

Produce multiple protein isoforms by including or excluding different exons.

Question 6

Which of the following is a direct result of RNA interference (RNAi) by microRNAs (miRNAs)?

Accepted Answer

Degradation of the target mRNA or inhibition of its translation.

Question 7

In the context of epigenetic inheritance, which of the following statements is correct?

Accepted Answer

Epigenetic changes can be inherited without changing the DNA sequence.

Question 8

A patient has a mutation that prevents the addition of a 5' cap to mRNA. What is the most likely consequence for gene expression?

Accepted Answer

The mRNA will be rapidly degraded and not translated.

Question 9

Which of the following posttranslational modifications is illustrated by the addition of a phosphate group to a protein, as shown in the provided images?

Accepted Answer

Phosphorylation

Question 10

In a scenario where a gene's promoter region is heavily methylated, what would you expect regarding the gene's expression?

Accepted Answer

The gene will be silenced or have very low expression.

Question 11

Which of the following best describes the function of small interfering RNAs (siRNAs) in gene regulation?

Accepted Answer

They recruit histone-modifying enzymes to form heterochromatin and silence genes.

Question 12

A researcher finds that a certain gene is only expressed in lens cells but not in liver cells. Which mechanism most likely explains this observation?

Accepted Answer

Specific transcription factors required for the gene's expression are only present in lens cells.

Question 13

Which of the following is an example of posttranscriptional regulation of gene expression?

Accepted Answer

Alternative splicing of pre-mRNA.

Question 14

A mutation in the gene encoding Dicer, an enzyme involved in miRNA processing, would most likely result in:

Accepted Answer

Increased translation of target mRNAs due to reduced miRNA-mediated silencing.

Question 15

Which of the following best explains why the same gene can produce different proteins in different tissues?

Accepted Answer

Alternative RNA splicing results in different combinations of exons being included in the mRNA.

Question 16

Which of the following equations best represents the process of phosphorylation of a protein?

Accepted Answer

$$	ext{Protein} + 	ext{ATP} \xrightarrow{	ext{Kinase}} 	ext{Protein-P} + 	ext{ADP}$$

Question 17

Which of the following scenarios best illustrates the effect of tissue-specific RNA editing?

Accepted Answer

The same mRNA is edited differently in the liver and intestine, resulting in proteins with different functions.

Question 18

Which of the following statements about general and specific transcription factors is correct?

Accepted Answer

General transcription factors are required for the transcription of all protein-coding genes.

Question 19

Which of the following is a likely consequence of a mutation that prevents the formation of transcription factories in the nucleus?

Accepted Answer

Genes from different chromosomes may not be efficiently transcribed together.

Question 20

Which of the following best describes the role of noncoding RNAs in chromatin remodeling?

Accepted Answer

They recruit histone-modifying enzymes to specific DNA regions, leading to heterochromatin formation.

Regulation of Gene Expression in Eukaryotes

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