Question 1

Which of the following best describes the role of histone acetyltransferases (HATs) in gene expression regulation?

Accepted Answer

They add acetyl groups to histones, resulting in decondensed chromatin and increased transcription.

Question 2

A mutation causes a transcription factor to lose its ability to bind to promoter-proximal elements. What is the most likely consequence for the associated gene?

Accepted Answer

The gene's transcription will be reduced or eliminated due to lack of activation.

Question 3

Which of the following is a direct effect of DNA methylation at promoter regions?

Accepted Answer

Recruitment of methyl DNA-binding proteins that inhibit transcription.

Question 4

During RNA interference (RNAi), which complex is responsible for binding and degrading target mRNA molecules?

Accepted Answer

RISC (RNA-induced silencing complex)

Question 5

A researcher observes that a gene is not expressed unless its enhancer is moved closer to the core promoter. What does this suggest about the function of enhancers?

Accepted Answer

Enhancers can regulate gene expression from a distance but may require proximity for optimal function.

Question 6

Which of the following best explains why chromatin remodeling is necessary for transcription initiation in eukaryotes?

Accepted Answer

Chromatin remodeling exposes DNA regulatory sequences by shifting nucleosomes.

Question 7

A point mutation changes a codon from $$\mathrm{GAA} to$$ $$\mathrm{GAG}. $$Both codons code for glutamic acid. What type of mutation is this?

Accepted Answer

Silent mutation

Question 8

Which of the following events occurs during post-transcriptional control of gene expression?

Accepted Answer

Splicing of introns from pre-mRNA

Question 9

A cell is exposed to a drug that inhibits the activity of histone deacetylases (HDACs). What is the most likely effect on gene expression?

Accepted Answer

Decreased chromatin condensation and increased transcription

Question 10

Which of the following best describes the 'Central Dogma' of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 11

A gene is transcribed at normal levels, but the protein product is not detected in the cell. Which regulatory mechanism is most likely responsible?

Accepted Answer

Translational inhibition or mRNA degradation

Question 12

Which of the following is a function of general transcription factors in eukaryotic transcription?

Accepted Answer

They recruit RNA polymerase II to the core promoter.

Question 13

A deletion mutation removes a single nucleotide from a coding sequence. What is the most likely consequence?

Accepted Answer

A frameshift mutation altering all downstream amino acids

Question 14

Which of the following best describes the function of the mediator complex in transcription?

Accepted Answer

It links regulatory transcription factors to RNA polymerase II, facilitating transcription initiation.

Question 15

A patient has a genetic disorder caused by a mutation in a regulatory transcription factor that normally binds to an enhancer. Which of the following is the most likely effect?

Accepted Answer

Reduced transcription of the target gene due to lack of enhancer activation

Question 16

Which of the following scenarios illustrates post-translational control of gene expression?

Accepted Answer

A protein is phosphorylated, altering its activity in response to a signal.

Question 17

If a mutation in a gene's core promoter prevents the binding of the TATA-binding protein (TBP), what is the most likely outcome?

Accepted Answer

Transcription will be severely reduced or absent.

Question 18

Which of the following best explains why alternative splicing increases protein diversity in eukaryotes?

Accepted Answer

It allows different combinations of exons to be joined, producing multiple proteins from one gene.

Question 19

A scientist discovers a protein that binds to DNA and recruits chromatin remodeling complexes, resulting in increased gene expression. This protein is most likely:

Accepted Answer

An activator

Question 20

Which of the following is a likely consequence of a nonsense mutation in the middle of a gene?

Accepted Answer

A truncated protein due to an early stop codon

C18&19Regulation of Gene Expression: Transcriptional, Translational, and Post-Translational Control

Guida di studio - Domande di pratica

Study guide - Flashcard