Question 1

Which of the following best explains why eukaryotic gene regulation is more complex than prokaryotic gene regulation?

Accepted Answer

Eukaryotic DNA is associated with histones and organized into chromatin, requiring multiple regulatory steps.

Question 2

What is the primary function of histone acetyltransferases (HATs) in gene regulation?

Accepted Answer

They add acetyl groups to histone tails, loosening chromatin and promoting transcription.

Question 3

Which of the following is a direct result of histone methylation?

Accepted Answer

Decreased transcription due to tighter packing of chromatin.

Question 4

A mutation in the gene encoding for a histone deacetylase (HDAC) results in a nonfunctional enzyme. What is the most likely effect on gene expression?

Accepted Answer

Chromatin will remain loosely packed, leading to increased transcription.

Question 5

Which of the following best describes the role of the SWI/SNF complex in chromatin remodeling?

Accepted Answer

It removes nucleosomes from DNA, making regions accessible to transcription factors.

Question 6

Which of the following is a characteristic of euchromatin?

Accepted Answer

It is uncoiled and transcriptionally active.

Question 7

Which of the following DNA elements is considered a cis-acting regulatory sequence?

Accepted Answer

Enhancer

Question 8

A gene is found to have multiple weak transcriptional start sites and is expressed at a steady level in all tissues. Which type of promoter does this gene most likely have?

Accepted Answer

Dispersed promoter

Question 9

Which of the following is the correct order of assembly for the pre-initiation complex (PIC) during eukaryotic transcription initiation?

Accepted Answer

TFIID binds to TATA box, then TFIIA and TFIIB, followed by RNA pol II and TFIIF, then TFIIE and TFIIH

Question 10

Which of the following statements about enhancers is TRUE?

Accepted Answer

They can be located thousands of base pairs away from the gene and still increase transcription.

Question 11

A researcher discovers a protein that binds to a silencer region of DNA and decreases the rate of transcription initiation. This protein is best described as a:

Accepted Answer

Repressor

Question 12

Which of the following modifications would most likely result in increased gene expression?

Accepted Answer

Addition of acetyl groups to histone tails

Question 13

Which of the following best explains why regulation at the transcriptional level is considered energetically favorable for the cell?

Accepted Answer

It prevents unnecessary synthesis of mRNA and proteins by stopping gene expression at the earliest step.

Question 14

Which of the following is NOT a function of general (basal) transcription factors?

Accepted Answer

Regulating the efficiency of transcription initiation above basal levels

Question 15

A mutation in the TATA box of a gene's promoter would most likely result in which of the following?

Accepted Answer

Reduced or abolished transcription initiation due to failure of transcription factor binding

Question 16

Which of the following best describes the difference between cis-acting and trans-acting elements?

Accepted Answer

Cis-acting elements are DNA sequences located on the same chromosome as the gene they regulate, while trans-acting elements are diffusible molecules that can regulate genes on different chromosomes.

Question 17

Which of the following scenarios best illustrates the role of a specific transcription factor in gene regulation?

Accepted Answer

A protein binds to an enhancer sequence and increases the rate of transcription initiation for a specific gene.

Question 18

Which of the following is a direct effect of chromatin condensation into heterochromatin?

Accepted Answer

Transcriptional repression due to reduced accessibility of DNA

Question 19

A gene is regulated by both an enhancer and a silencer. Which of the following best describes how these elements interact to control gene expression?

Accepted Answer

The enhancer increases transcription initiation, while the silencer decreases it, allowing for fine-tuned regulation.

Question 20

Which of the following best describes the two functional domains of a transcription factor?

Accepted Answer

A DNA-binding domain and a trans-activating domain

Chap 17 pt 1

Guida di studio - Domande di pratica

Study guide - Flashcard