Q: Which equation best describes the steady-state level of mRNA in a cell?

$$\text{Steady-state mRNA} = \text{Transcription rate} - \text{Decay rate}$$

Question 1

Which of the following is a primary mechanism by which chromatin structure regulates gene expression in eukaryotes?

Accepted Answer

By altering the accessibility of DNA to transcription factors through nucleosome modifications

Question 2

Histone acetylation is associated with which of the following outcomes in gene regulation?

Accepted Answer

Increased transcription due to reduced affinity of histones for DNA

Question 3

DNA methylation most commonly occurs at which position and nucleotide sequence in eukaryotes?

Accepted Answer

At the 5 position of cytosine in CpG islands

Question 4

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

Accepted Answer

$$	ext{Steady-state mRNA} = 	ext{Transcription rate} - 	ext{Decay rate}$$

Question 5

A mutation in the TATA box of a gene’s promoter is most likely to result in:

Accepted Answer

Decreased transcription initiation

Question 6

Which of the following statements about alternative splicing is correct?

Accepted Answer

Alternative splicing allows a single gene to produce multiple protein isoforms

Question 7

Which of the following is a function of the proteasome in gene expression regulation?

Accepted Answer

Degrading proteins tagged with ubiquitin

Question 8

Which of the following best describes the role of enhancers in gene regulation?

Accepted Answer

Enhancers increase the rate of transcription and confer tissue-specific expression

Question 9

Which of the following is a cis-acting element involved in transcription regulation?

Accepted Answer

TATA box

Question 10

A cell is exposed to low oxygen levels. Which gene regulatory mechanism is most likely to be activated?

Accepted Answer

Upregulation of erythropoietin gene expression

Question 11

Which of the following is NOT a typical modification found on the N-terminal tails of histone proteins?

Accepted Answer

Glycosylation

Question 12

Which of the following best explains why mutations in RNA-binding proteins can lead to genetic disorders such as myotonic dystrophy?

Accepted Answer

They disrupt alternative splicing, leading to abnormal protein isoforms

Question 13

Which of the following equations represents the number of possible protein isoforms produced by alternative splicing of the Drosophila Dscam gene, given 12 alternatives for exon 4, 48 for exon 6, 33 for exon 9, and 2 for exon 17?

Accepted Answer

$$12 	imes 48 	imes 33 	imes 2$$

Question 14

Which of the following is a characteristic of dispersed core promoters?

Accepted Answer

They direct initiation from several weak transcriptional start sites over a region

Question 15

Which of the following statements about nonsense-mediated decay (NMD) is correct?

Accepted Answer

NMD eliminates mRNAs with premature stop codons to prevent wasteful or toxic translation

Question 16

Which of the following is a function of the zip code element in actin mRNA localization?

Accepted Answer

It serves as a binding site for zip code binding protein 1 (ZBP1), directing mRNA to the cell periphery

Question 17

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

Accepted Answer

DNA looping delivers activators and general transcription factors to the promoter region, increasing PIC assembly

Question 18

Which of the following is a role of ubiquitin ligases in posttranslational regulation?

Accepted Answer

They recognize and catalyze the addition of ubiquitin residues to target proteins

Question 19

Which of the following is a plausible consequence of a mutation in the CAAT box of a gene’s promoter?

Accepted Answer

Reduced basal transcription levels

Question 20

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

Accepted Answer

A DNA-binding protein that influences expression of multiple genes

Ch 16 Regulation of Gene Expression in Eukaryotes – Study Notes

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