Question 1

Which of the following best describes the role of chromatin decondensation in gene expression regulation?

Accepted Answer

It allows the promoter region to become accessible to the transcriptional machinery, enabling gene expression.

Question 2

A mutation in the gene encoding a ubiquitin ligase (E3) would most likely result in which of the following cellular outcomes?

Accepted Answer

Accumulation of proteins that should be degraded, potentially leading to cellular dysfunction.

Question 3

Which process allows a single gene to produce multiple protein variants in eukaryotic cells?

Accepted Answer

Alternative splicing of pre-mRNA.

Question 4

What is the primary function of general transcription factors in eukaryotic gene expression?

Accepted Answer

They are essential for the transcription of all genes transcribed by a given type of RNA polymerase.

Question 5

Which of the following mechanisms is used by mammalian red blood cells to regulate gene expression at the genomic level?

Accepted Answer

Gene deletion.

Question 6

A scientist observes that a certain mRNA has a very short poly(A) tail. What is the most likely consequence for this mRNA?

Accepted Answer

It will be rapidly degraded, resulting in decreased protein production.

Question 7

Which of the following best explains how V(D)J recombination contributes to immune system diversity?

Accepted Answer

It rearranges DNA segments in lymphocyte receptor genes, generating a vast array of antigen receptors.

Question 8

Which of the following is a posttranslational modification that can alter protein function?

Accepted Answer

Phosphorylation of specific amino acid residues.

Question 9

A cell is exposed to a drug that inhibits the SWI/SNF chromatin remodeling complex. What is the most likely effect on gene expression?

Accepted Answer

Decreased accessibility of chromatin, leading to reduced transcription of certain genes.

Question 10

Which of the following equations best represents the ATP-dependent activation of ubiquitin in the ubiquitin-proteasome system?

Accepted Answer

$$\mathrm{Ubiquitin} + \mathrm{E1} + \mathrm{ATP} \rightarrow \mathrm{Ubiquitin{-}E1} + \mathrm{AMP} + \mathrm{PP_i}$$

Question 11

Which of the following scenarios best illustrates translational control of gene expression?

Accepted Answer

Phosphorylation of eIF2 inhibits the initiation of translation for specific mRNAs.

Question 12

A mutation causes a transcriptional activator to lose its ability to bind to an enhancer. What is the most likely effect on the target gene?

Accepted Answer

Decreased transcription of the target gene.

Question 13

Which of the following is NOT a level at which eukaryotic gene expression is regulated?

Accepted Answer

DNA replication control.

Question 14

A patient has a genetic disorder that prevents the addition of ubiquitin to proteins. Which cellular process is most directly affected?

Accepted Answer

Proteasomal degradation of proteins.

Question 15

Which of the following best describes the function of a transcriptional repressor?

Accepted Answer

It binds to a silencer element and decreases transcription of the associated gene.

Question 16

Which of the following is a real-life example of gene amplification?

Accepted Answer

Production of multiple copies of rRNA genes in rapidly dividing cells.

Question 17

Which of the following statements about mRNA stability is correct?

Accepted Answer

A long poly(A) tail increases mRNA stability, allowing for more protein to be produced.

Question 18

Which of the following best explains why selective gene expression is important for multicellular organisms?

Accepted Answer

It allows different cell types to synthesize only the proteins they need, increasing efficiency.

Question 19

Which of the following is a direct consequence of histone acetylation?

Accepted Answer

Increased accessibility of chromatin to transcriptional machinery.

The Regulation of Gene Expression in Eukaryotes

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