Question 1

Which of the following chromatin modifications is most directly associated with increased gene expression activity?

Accepted Answer

Histone acetylation by histone acetyltransferase (HAT)

Question 2

A mutation causes the loss of function of the SWI/SNF chromatin remodeling complex in a human cell. Which of the following is the most likely consequence?

Accepted Answer

Decreased gene expression due to compacted chromatin

Question 3

Which of the following best describes the role of DNA methylation in gene regulation?

Accepted Answer

It represses gene expression by inhibiting transcription factor binding

Question 4

A gene contains a TATA box, BRE, and DPE in its promoter region. What is the primary function of these elements?

Accepted Answer

They determine the accurate initiation of transcription

Question 5

Which of the following is a cis-acting sequence that can repress gene expression?

Accepted Answer

Silencer

Question 6

A researcher observes that a particular gene is expressed at high levels in liver cells but not in muscle cells. Which regulatory mechanism is most likely responsible for this tissue-specific expression?

Accepted Answer

Binding of tissue-specific transcription factors to enhancers

Question 7

Which of the following statements about alternative splicing is correct?

Accepted Answer

It generates multiple mRNA isoforms from identical pre-mRNA

Question 8

A mutation in the gene encoding a splicing enhancer protein leads to misregulation of alternative splicing. Which disease is most likely associated with this defect?

Accepted Answer

Spinal muscular atrophy (SMA)

Question 9

Which equation best represents the steady-state level of mRNA in a cell?

Accepted Answer

$$mRNA_{steady-state} = Rate_{transcription} - Rate_{degradation}$$

Question 10

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

Accepted Answer

Transcription factor

Question 11

A scientist discovers a mutation that prevents the addition of acetyl groups to histone tails. What is the most likely effect on gene expression?

Accepted Answer

Decreased gene expression due to compact chromatin

Question 12

Which of the following best describes the function of insulators in gene regulation?

Accepted Answer

They prevent enhancers from activating non-target genes

Question 13

Which posttranscriptional regulatory mechanism involves short RNA molecules that repress gene expression by targeting mRNA for degradation?

Accepted Answer

RNA interference (RNAi)

Question 14

Which of the following posttranslational modifications is most commonly associated with changes in protein conformation and activity?

Accepted Answer

Phosphorylation

Question 15

A protein is tagged with ubiquitin. What is the most likely fate of this protein?

Accepted Answer

It will be degraded by the proteasome

Question 16

Which of the following is true regarding focused and dispersed promoters?

Accepted Answer

Dispersed promoters are common in vertebrates and initiate transcription from several weak start sites

Question 17

Which of the following is NOT a component of the core promoter structure?

Accepted Answer

Enhancer

Question 18

Which process increases the number of proteins produced from a single gene without increasing the number of genes in the genome?

Accepted Answer

Alternative splicing

Question 19

A cell exhibits high levels of microRNAs targeting a specific mRNA. What is the expected effect on the protein encoded by that mRNA?

Accepted Answer

Decreased protein levels due to mRNA degradation

Question 20

Which of the following best explains how chromatin remodeling can activate gene expression?

Accepted Answer

By repositioning nucleosomes to expose promoter regions to transcription machinery

Regulation of Gene Expression: Mechanisms and Molecular Control in Eukaryotes

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