Question 1

Which of the following statements best explains why humans and chimpanzees have large phenotypic differences despite high genetic similarity?

Accepted Answer

Changes in a relatively small number of regulatory sequences.

Question 2

Which process must occur before transcription can begin in eukaryotic cells?

Accepted Answer

DNA must unwind from histone proteins.

Question 3

What is the primary effect of acetylation of histone proteins on gene expression?

Accepted Answer

It alters chromatin structure, permitting some transcription factors to bind to DNA.

Question 4

In Arabidopsis, which gene encodes a deacetylase enzyme that controls flowering?

Accepted Answer

FLD

Question 5

Which of the following best describes the function of chromatin-remodeling complexes?

Accepted Answer

They bind directly to DNA sites and reposition nucleosomes.

Question 6

DNA methylation most commonly occurs at which type of nucleotide sequence in eukaryotes?

Accepted Answer

CpG islands (cytosine bases adjacent to guanine nucleotides)

Question 7

Which experimental technique is used to identify DNA-binding sites of specific proteins and the locations of modified histone proteins?

Accepted Answer

Chromatin immunoprecipitation (ChIP)

Question 8

Transcription factors regulate gene expression by:

Accepted Answer

Binding to sites on DNA and regulating transcription.

Question 9

Which statement about enhancers and silencers is correct?

Accepted Answer

Both enhancers and silencers are position and orientation independent and contain binding sites for transcription factors.

Question 10

An insulator sequence in DNA functions to:

Accepted Answer

Block the action of an enhancer on a promoter when the insulator lies between them.

Question 11

Which of the following is a mechanism by which RNA interference regulates gene expression?

Accepted Answer

RNA cleavage, inhibition of translation, and transcriptional silencing.

Question 12

Alternative splicing of pre-mRNA can result in:

Accepted Answer

Production of different proteins from the same gene.

Question 13

Which of the following is TRUE regarding the regulation of translation in eukaryotic cells?

Accepted Answer

The availability of ribosomes, charged tRNAs, and initiation factors can affect the rate of translation.

Question 14

Which of the following best describes the role of response elements in coordinated gene regulation?

Accepted Answer

They are common regulatory elements upstream of the start sites of a group of genes responding to a common stimulus.

Question 15

In Drosophila, alternative splicing of the tra pre-mRNA is crucial for:

Accepted Answer

Sex determination.

Question 16

Which of the following is a difference between gene regulation in bacteria and eukaryotes?

Accepted Answer

Bacteria primarily regulate gene expression at the level of transcription, while eukaryotes regulate at many levels.

Question 17

Which of the following is a correct sequence of events for RNA interference by siRNA?

Accepted Answer

Dicer cleaves double-stranded RNA $$\rightarrow$$ siRNA combines with RISC $$\rightarrow$$ RISC pairs with mRNA $$\rightarrow$$ mRNA is cleaved.

Question 18

A mutation that prevents the removal of the 5'-cap from mRNA would most likely result in:

Accepted Answer

Increased stability of the mRNA and decreased degradation.

Question 19

Which of the following is a real-world example of gene regulation by the availability of translation components?

Accepted Answer

Exposure to an antigen increases initiation factors, leading to T-cell proliferation.

Question 20

Which of the following statements about small interfering RNAs (siRNAs) and microRNAs (miRNAs) is correct?

Accepted Answer

siRNAs base-pair perfectly with mRNAs, while miRNAs often form less-than-perfect pairings.

Control of Gene Expression in Bacteria and Eukaryotes: Mechanisms and Comparisons

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