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 process in eukaryotic gene regulation?

Accepted Answer

Basal transcription by facilitating RNA polymerase binding to the core promoter

Question 3

A regulatory protein binds to a DNA sequence called an enhancer. What is the most likely outcome?

Accepted Answer

Transcription rate increases due to up-regulation

Question 4

Which of the following is NOT a common way that the function of regulatory transcription factors is modulated?

Accepted Answer

Direct DNA replication

Question 5

The glucocorticoid hormone activates gene expression by binding to its receptor, which then:

Accepted Answer

Forms a dimer that enters the nucleus and binds to a glucocorticoid response element (GRE)

Question 6

CREB protein acts as a transcriptional activator only after which event?

Accepted Answer

It is phosphorylated by protein kinase

Question 7

Which of the following chromatin states is most accessible to transcription factors and allows transcription to occur?

Accepted Answer

Open conformation (euchromatin)

Question 8

ATP-dependent chromatin remodeling can result in all of the following EXCEPT:

Accepted Answer

Direct synthesis of mRNA

Question 9

Histone acetylation generally leads to which effect on chromatin structure and gene expression?

Accepted Answer

Chromatin becomes more open and gene expression is activated

Question 10

A nucleosome-free region (NFR) is typically found at which location in a protein-encoding gene?

Accepted Answer

At the transcriptional start site and termination site

Question 11

During transcriptional activation, what is the role of activator proteins in relation to chromatin remodeling and histone modification?

Accepted Answer

They recruit chromatin remodeling complexes and histone modification enzymes

Question 12

DNA methylation typically silences gene expression by:

Accepted Answer

Blocking the binding of activator proteins to enhancer elements

Question 13

Insulator sequences in eukaryotic genomes function primarily to:

Accepted Answer

Block the regulatory effects of neighboring genes

Question 14

Which of the following best describes the regulation of ferritin translation in response to high iron levels?

Accepted Answer

Iron binds to IRP, preventing it from binding to the IRE, allowing ferritin mRNA translation

Question 15

In the regulation of transferrin receptor mRNA, what happens when iron levels are high?

Accepted Answer

Iron binds to IRP, causing it to dissociate from the IRE, leading to mRNA degradation

Question 16

Rubinstein-Taybi Syndrome is associated with mutations in genes encoding which type of protein?

Accepted Answer

CREB-binding protein responsible for histone acetylation

Question 17

Which equation best represents the relationship between the rate of transcription ($$R) $$and the presence of an activator bound to an enhancer, given that up-regulation can be 10- to 1,000-fold?

Accepted Answer

$$R = R_0$ 	imes F$$, where $$F is $$between 10 and 1,000

Question 18

A mutation that prevents histone acetylation would most likely result in:

Accepted Answer

Decreased gene expression due to closed chromatin

Question 19

Which of the following is a multi-step process required for transcriptional activation in eukaryotes?

Accepted Answer

Binding of activator proteins to enhancers, recruitment of chromatin remodeling complexes, histone modification, and formation of the preinitiation complex

Question 20

Which of the following statements about combinatorial control is correct?

Accepted Answer

Various combinations of regulatory proteins can contribute to the regulation of a single gene

Gene Regulation in Eukaryotes: Mechanisms and Factors

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