Question 1

Which of the following statements best describes the role of general transcription factors (GTFs) in eukaryotic transcription initiation?

Accepted Answer

GTFs are necessary for recruitment of RNA polymerase II to the core promoter but are not sufficient for physiological levels of transcription.

Question 2

In prokaryotes, transcriptional specificity under different environmental conditions is primarily achieved by:

Accepted Answer

Sigma factor switching, which allows RNA polymerase to recognize different promoter sequences.

Question 3

During the ordered assembly of the eukaryotic preinitiation complex (PIC), which factor binds first to the TATA box?

Accepted Answer

TFIID (TBP + TAFs)

Question 4

Which activity of TFIIH is directly responsible for melting the DNA at the promoter during transcription initiation?

Accepted Answer

Its helicase activity

Question 5

What is the function of the carboxy-terminal domain (CTD) of RNA polymerase II during transcription?

Accepted Answer

It provides binding sites for RNA processing enzymes and is subject to multiple phosphorylation events.

Question 6

Which of the following is TRUE regarding the fate of transcription factors during promoter escape in eukaryotic transcription?

Accepted Answer

Most transcription factors are released, but TFIIH remains associated with the polymerase during elongation.

Question 7

The consensus sequence for the eukaryotic core promoter region recognized by TBP is:

Accepted Answer

TATA box

Question 8

Which of the following best explains why eukaryotic mRNA must be processed before translation?

Accepted Answer

Eukaryotic mRNA contains introns that must be removed to produce a functional coding sequence.

Question 9

Which of the following modifications occurs at the 5' end of eukaryotic pre-mRNA during processing?

Accepted Answer

Addition of a 7-methylguanylate cap

Question 10

What is the primary function of the 7-methylguanylate cap added to the 5' end of eukaryotic mRNA?

Accepted Answer

It protects the mRNA from 5' to 3' exonucleases and aids in translation initiation.

Question 11

Which sequence acts as a signal for transcription termination and polyadenylation in eukaryotic mRNA?

Accepted Answer

AAUAAA

Question 12

During splicing, which consensus sequence is found at the branch point in yeast?

Accepted Answer

UACUAAC

Question 13

Which of the following is a consequence of a mutation at the 3' splice site of an intron?

Accepted Answer

Intron retention and possible exon loss

Question 14

Which enzyme is responsible for adding the 7-methylguanylate cap to the 5' end of eukaryotic mRNA?

Accepted Answer

Guanylyl transferase

Question 15

What is the correct order of events in eukaryotic mRNA processing?

Accepted Answer

Capping, splicing, polyadenylation

Question 16

Which of the following best describes the structure of the carboxy-terminal domain (CTD) of RNA polymerase II?

Accepted Answer

Multiple repeats of a 7-amino acid sequence: YSPTSPS, with 52 repeats in humans

Question 17

Which of the following is NOT a function of TFIIH during transcription?

Accepted Answer

Directly catalyzing polyadenylation of mRNA

Question 18

A mutation in the branch point sequence of an intron would most likely result in:

Accepted Answer

Impaired splicing and possible intron retention

Question 19

Which of the following equations correctly represents the initial structure of a newly synthesized eukaryotic mRNA before capping?

Accepted Answer

$$pppN_1pN_2pN_3p...$$

Question 20

Which of the following statements best explains why prokaryotic mRNA does not require extensive processing before translation?

Accepted Answer

Transcription and translation are coupled, and mRNA is translated as it is being synthesized.

Eukaryotic Transcription and RNA Processing

Guida di studio - Domande di pratica