Question 1

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

Accepted Answer

Direct translation of pre-mRNA without modification

Question 2

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

Accepted Answer

It facilitates mRNA export from the nucleus and protects against exonucleases

Question 3

In prokaryotes, why can translation begin before transcription is complete?

Accepted Answer

There is no nuclear membrane, allowing ribosomes to access mRNA as it is being synthesized

Question 4

Which equation correctly represents the initial structure of a newly synthesized eukaryotic mRNA before processing?

Accepted Answer

$$pppN_1pN_2pN_3p...$$

Question 5

A mutation occurs at the branch point sequence of an intron. What is the most likely consequence?

Accepted Answer

Retention of the intron in the mature mRNA

Question 6

Which of the following best describes the role of the spliceosome in mRNA processing?

Accepted Answer

It removes introns and joins exons together

Question 7

A patient has a mutation in the donor site (5' splice site) of a gene. Which outcome is most likely?

Accepted Answer

Exon skipping and possible frameshift mutation

Question 8

Which consensus sequence is typically found upstream of the 3' splice site in eukaryotic introns?

Accepted Answer

UACUAAC

Question 9

During mRNA processing, which enzyme is responsible for adding the 7-methylguanylate cap?

Accepted Answer

Guanylyl transferase

Question 10

Which of the following statements about introns and exons is correct?

Accepted Answer

Introns are noncoding regions that are removed from pre-mRNA

Question 11

A mutation in the promoter region of a gene can lead to which of the following?

Accepted Answer

Altered gene expression levels

Question 12

Which process is coupled with transcription in eukaryotes, but not in prokaryotes?

Accepted Answer

mRNA processing (capping, splicing, polyadenylation)

Question 13

If an intron is not a multiple of 3 nucleotides and is retained in the mature mRNA, what is the most likely effect on the protein product?

Accepted Answer

Frameshift mutation leading to a premature stop codon

Question 14

Which of the following is a function of the PolyA tail added to eukaryotic mRNA?

Accepted Answer

Facilitates mRNA export from the nucleus and increases stability

Question 15

Which equation best represents the mature, capped, and polyadenylated eukaryotic mRNA?

Accepted Answer

$$m^7$$GpppN_1pN_2pN_3p...A_n$$

Question 16

Which of the following is TRUE regarding the spatial separation of transcription and translation in eukaryotes?

Accepted Answer

Transcription occurs in the nucleus, and translation occurs in the cytoplasm

Question 17

A mutation causes the loss of the 5' cap on an mRNA molecule. What is the most likely consequence?

Accepted Answer

Decreased mRNA export and increased degradation by exonucleases

Question 18

Which of the following is a direct consequence of a mutation at a splice junction?

Accepted Answer

Intron retention or exon skipping

Question 19

Which RNA polymerase is responsible for synthesizing pre-mRNA in eukaryotes?

Accepted Answer

RNA polymerase II

Question 20

Which of the following best explains why nuclear RNA is larger than mature mRNA?

Accepted Answer

Nuclear RNA contains both introns and exons before processing

Eukaryotic Transcription and mRNA Processing

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