Q: Which equation best represents the effect of histone acetyltransferase (HAT) activity on chromatin structure?

$\text{Chromatin} + \text{HAT} \rightarrow \text{Chromatin}_{\text{acetylated}}$

Question 1

Which of the following best explains why nerve and muscle cells have distinct appearances and functions, despite having identical DNA content?

Accepted Answer

Gene regulation resulting in differential gene expression

Question 2

General transcription factors such as TFIID and TFIIH are required for which of the following processes?

Accepted Answer

Binding of RNA polymerase to the core promoter and progression to elongation

Question 3

A regulatory protein that increases the rate of transcription by binding to a specific DNA sequence is called a(n) _____, and the DNA sequence it binds is called a(n) _____.

Accepted Answer

activator; enhancer

Question 4

Which of the following mechanisms is NOT a way that regulatory transcription factor function can be modulated?

Accepted Answer

Alternative splicing of mRNA

Question 5

The binding of a transcription factor to a silencer sequence results in:

Accepted Answer

Down-regulation of gene expression

Question 6

Which of the following best describes the effect of DNA methylation on gene expression?

Accepted Answer

It silences gene expression by preventing activator binding

Question 7

A mutation that prevents the phosphorylation of the CREB protein would most likely result in which of the following?

Accepted Answer

CREB protein failing to activate transcription

Question 8

Which of the following chromatin conformations is most accessible to transcription factors and allows transcription to take place?

Accepted Answer

Euchromatin (open conformation)

Question 9

ATP-dependent chromatin remodeling complexes can alter nucleosome position by all of the following EXCEPT:

Accepted Answer

Recruiting DNA methyltransferases to methylate DNA

Question 10

Histone acetylation generally results in:

Accepted Answer

More open chromatin and increased transcription

Question 11

Which equation best represents the effect of histone acetyltransferase (HAT) activity on chromatin structure?

Accepted Answer

$	ext{Chromatin} + 	ext{HAT} ightarrow 	ext{Chromatin}_{	ext{acetylated}}$

Question 12

A patient with Rubinstein-Taybi Syndrome is found to have a mutation in the gene encoding the CREB-binding protein (CBP). Which molecular defect is most likely present?

Accepted Answer

Impaired histone acetylation

Question 13

Which of the following is a function of insulator sequences in eukaryotic gene regulation?

Accepted Answer

Blocking the regulatory effects of neighboring genes

Question 14

In the regulation of iron assimilation, what is the effect of high iron levels on ferritin mRNA translation?

Accepted Answer

Iron binds to IRP, preventing its binding to IRE, allowing translation of ferritin mRNA

Question 15

Which of the following best describes the role of the nucleosome-free region (NFR) near the transcriptional start site?

Accepted Answer

It allows binding of general transcription factors and RNA polymerase

Question 16

Which of the following scenarios would most likely result in increased transcription of a gene?

Accepted Answer

Histone acetylation near the promoter region

Question 17

If a mutation prevents the formation of the preinitiation complex at a gene's core promoter, which process will be directly affected?

Accepted Answer

Transcription initiation

Question 18

Which of the following equations best represents the effect of DNA methylation on gene expression?

Accepted Answer

$	ext{Gene}_{	ext{active}} + 	ext{DNA methylation} ightarrow 	ext{Gene}_{	ext{silenced}}$

Question 19

Which of the following is a direct consequence of histone deacetylase (HDAC) activity?

Accepted Answer

Conversion of chromatin to a more closed conformation

Gene Regulation in Eukaryotes: Mechanisms and Molecular Players

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