Question 1

Which of the following best describes the role of transcription factors in eukaryotic gene expression?

Accepted Answer

They are proteins that help RNA polymerase bind to the promoter and initiate transcription.

Question 2

During eukaryotic mRNA processing, which modification is added to the 5' end of the pre-mRNA?

Accepted Answer

A methylated guanosine cap

Question 3

What is the primary function of the 3' poly(A) tail in eukaryotic mRNA?

Accepted Answer

It increases mRNA stability and protects it from nucleases.

Question 4

Which sequence signals the addition of the poly(A) tail during mRNA processing?

Accepted Answer

AAUAAA

Question 5

A mutation causes improper splicing of pre-mRNA, resulting in a nonfunctional protein. Which process is most directly affected?

Accepted Answer

Removal of introns and joining of exons

Question 6

Which of the following is TRUE regarding the difference between prokaryotic and eukaryotic mRNA processing?

Accepted Answer

Eukaryotic mRNA is processed with a 5' cap and poly(A) tail before export from the nucleus.

Question 7

Which enzyme is responsible for adding the poly(A) tail to the 3' end of eukaryotic mRNA?

Accepted Answer

Poly(A) polymerase

Question 8

What is the correct order of events in eukaryotic gene expression from DNA to protein?

Accepted Answer

Transcription → RNA processing → Translation

Question 9

Which of the following statements about introns is correct?

Accepted Answer

Introns are removed from pre-mRNA during splicing.

Question 10

A researcher observes a lariat structure during mRNA processing. What does this indicate?

Accepted Answer

An intron is being removed during splicing.

Question 11

Which of the following is a function of the exon junction complex (EJC) in mRNA processing?

Accepted Answer

It is required for efficient export of mRNA from the nucleus.

Question 12

Which snRNP is the first to bind to the pre-mRNA during spliceosome assembly?

Accepted Answer

U1

Question 13

If a mutation occurs at the branch-point adenine during splicing, what is the most likely consequence?

Accepted Answer

Failure to form the lariat structure, leading to improper intron removal.

Question 14

Which process is represented by the equation $$\mathrm{DNA} \rightarrow \mathrm{RNA}$$?

Accepted Answer

Transcription

Question 15

A patient has a genetic disease caused by a splicing error that leads to a nonfunctional protein. Which molecular event most likely occurred?

Accepted Answer

Exons were incorrectly joined, resulting in a frameshift mutation.

Question 16

Which of the following is NOT a step in eukaryotic mRNA processing?

Accepted Answer

Direct translation of pre-mRNA without modification

Question 17

Which of the following best explains why the 5' cap is important for mRNA?

Accepted Answer

It protects mRNA from degradation and helps ribosome binding.

Question 18

Which of the following is a consequence of a mutation in the AAUAAA sequence of a gene?

Accepted Answer

Failure to add the poly(A) tail, resulting in unstable mRNA.

Question 19

Which process allows RNA to be synthesized from an RNA template, as seen in some viruses?

Accepted Answer

RNA replication

Question 20

Which of the following is TRUE about heterogeneous nuclear RNA (hnRNA)?

Accepted Answer

It refers to the primary transcript before processing in the nucleus.

Gene Expression I: The Genetic Code and Transcription – Study Notes

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