Question 1

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

Accepted Answer

They catalyze the addition of acetyl groups to histone tails, decreasing the positive charge and increasing transcription.

Question 2

A mutation in the TATA box of a core promoter is most likely to result in which of the following?

Accepted Answer

Reduced accuracy and efficiency of transcription initiation.

Question 3

Which of the following is a direct consequence of DNA methylation at CpG islands in eukaryotic gene promoters?

Accepted Answer

Silencing of gene expression by preventing transcription factor binding.

Question 4

A researcher observes that a single gene produces multiple protein isoforms in different tissues. Which mechanism most likely explains this observation?

Accepted Answer

Alternative splicing of pre-mRNA.

Question 5

Which of the following statements about enhancers is correct?

Accepted Answer

They can function at great distances from the gene and increase transcription rates.

Question 6

A mutation in a gene causes the loss of function of a ubiquitin ligase. What is the most likely cellular consequence?

Accepted Answer

Proteins will accumulate due to decreased degradation by the proteasome.

Question 7

Which of the following best explains why the number of proteins in the human proteome exceeds the number of genes in the genome?

Accepted Answer

Alternative splicing of pre-mRNA.

Question 8

A patient with myotonic dystrophy has a mutation that disrupts normal RNA splicing. This is an example of which type of genetic disorder?

Accepted Answer

Spliceopathy

Question 9

Which of the following is a function of the proteasome in eukaryotic cells?

Accepted Answer

Degrading proteins tagged with ubiquitin.

Question 10

Which of the following best describes the recruitment model of transcription regulation?

Accepted Answer

DNA looping brings activators and general transcription factors to the promoter, increasing pre-initiation complex assembly.

Question 11

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

Accepted Answer

Dispersed promoters are used by most higher eukaryotes and have several weak start sites.

Question 12

A gene contains a mutation in its CAAT box. What is the most likely effect on gene expression?

Accepted Answer

Reduced basal transcription levels due to impaired binding of transcription factors.

Question 13

Which of the following mechanisms is responsible for the rapid degradation of mRNAs containing premature stop codons?

Accepted Answer

Nonsense-mediated decay

Question 14

Which of the following is a direct effect of histone acetylation on chromatin structure?

Accepted Answer

Decreases the positive charge of histones, loosening DNA binding and promoting transcription.

Question 15

A mutation prevents the phosphorylation of a transcription factor. Which enzyme is most likely unable to act on this protein?

Accepted Answer

Kinase

Question 16

Which of the following is a function of RNA-binding proteins (RBPs) in gene regulation?

Accepted Answer

They bind to specific RNA sequences to regulate alternative splicing.

Question 17

Which of the following best describes the role of the zip code sequence in actin mRNA?

Accepted Answer

It serves as a cis-regulatory element that directs mRNA localization within the cell.

Question 18

Which of the following is a direct result of deadenylation-dependent mRNA decay?

Accepted Answer

Shortening of the poly-A tail, leading to mRNA degradation.

Question 19

Which of the following is a characteristic of silencers in eukaryotic gene regulation?

Accepted Answer

They act as negative regulators, repressing transcription in a tissue- or temporal-specific manner.

Question 20

Which of the following best explains why mutations in the promoter region can have significant effects on gene expression?

Accepted Answer

Promoter mutations can disrupt binding sites for transcription factors, altering transcription levels.

Regulation of Gene Expression in Eukaryotes – Study Notes

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