Question 1

AZA is a compound that inhibits DNA methylation. What is the most likely effect of treating cancer cells with AZA?

Accepted Answer

Decreased DNA methylation resulting in activation of previously silenced genes.

Question 2

TSA inhibits histone deacetylase. What is the expected effect on chromatin structure and transcription?

Accepted Answer

Chromatin becomes less condensed and transcription increases.

Question 3

A researcher applies both AZA and TSA to cancer cells. What is the most likely combined effect on gene expression?

Accepted Answer

Both drugs will activate gene expression by reducing methylation and increasing acetylation.

Question 4

Methylation of the MGMT promoter is associated with improved response to temozolomide in glioblastoma patients. What is the most likely reason for this?

Accepted Answer

Methylation silences MGMT, reducing DNA repair and making cancer cells more sensitive to temozolomide.

Question 5

Which of the following best describes the clinical implication of MGMT promoter methylation in glioblastoma?

Accepted Answer

Patients with methylated MGMT promoter have improved survival after temozolomide treatment.

Question 6

A scientist uses a synthetic miRNA inhibitor to prevent binding of miRNAs to the target mRNA in immune cells. What is the most likely outcome?

Accepted Answer

Increased translation of the target mRNA and higher protein levels.

Question 7

Researchers are studying a gene involved in neuron development. They use a histone acetyltransferase (HAT) activator. What is the most likely effect on gene expression?

Accepted Answer

Gene expression will increase due to chromatin relaxation and easier access for transcription machinery.

Question 8

A researcher introduces a synthetic molecule that blocks the binding site for a transcription factor (TF) on a gene involved in muscle development. What is the most likely effect?

Accepted Answer

The gene will be underexpressed because the TF cannot bind and activate transcription.

Question 9

During heart development, a gene can be spliced into two forms: Form F (fetal) and Form A (adult). In some people with heart problems, splicing switches off Form F early. What is the most likely result?

Accepted Answer

Heart growth is impaired because Form F is needed for early development.

Question 10

A researcher wants to reverse the effects of a maternal low-protein diet on offspring gene expression. Which treatment would most likely be effective?

Accepted Answer

Apply a DNA methyltransferase inhibitor to decrease methylation.

Question 11

If researchers treat offspring cells with a histone acetyltransferase (HAT) activator after a maternal low-protein diet, what would likely happen to Hnf4a expression?

Accepted Answer

Hnf4a expression would increase due to chromatin relaxation.

Question 12

Which of the following is a post-transcriptional regulation mechanism?

Accepted Answer

RNA interference (miRNA/siRNA)

Question 13

Which process adds a poly-A tail to mRNA and what is its main function?

Accepted Answer

Post-transcriptional modification; increases mRNA stability and translation efficiency

Question 14

A scientist wants to reduce production of a harmful protein without permanently changing DNA. Which category of regulation should be targeted?

Accepted Answer

Post-transcriptional regulation

Question 15

Which equation best represents the relationship between gene expression and DNA methylation?

Accepted Answer

$	ext{Gene Expression} \propto \frac{1}{	ext{DNA Methylation}}$

Question 16

Which of the following is most likely to result from increased histone acetylation?

Accepted Answer

Chromatin relaxation and increased gene expression

Question 17

A mutation causes loss of function in a gene encoding a histone deacetylase. What is the most likely effect on gene expression?

Accepted Answer

Gene expression will increase due to chromatin relaxation.

Question 18

Which process is most directly responsible for turning genes off after successful transcription?

Accepted Answer

RNA interference (miRNA)

Question 19

Which of the following is a real-world example of post-translational regulation?

Accepted Answer

Addition of a phosphate group to a protein to activate or deactivate its function

Gene Expression Regulation: Mechanisms and Applications

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