Question 1

Which of the following best describes the function of the 5′ cap added to eukaryotic pre-mRNA during RNA processing?

Accepted Answer

It facilitates the export of mRNA from the nucleus, protects mRNA from degradation, and helps ribosomes attach to the 5′ end.

Question 2

What is the main consequence of alternative RNA splicing in eukaryotic cells?

Accepted Answer

It allows a single gene to code for multiple polypeptides.

Question 3

During RNA processing, what is the role of the poly-A tail added to the 3′ end of pre-mRNA?

Accepted Answer

It facilitates mRNA export, protects mRNA from degradation, and assists in translation initiation.

Question 4

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

Accepted Answer

Introns are noncoding regions removed from pre-mRNA, while exons remain and are usually expressed.

Question 5

A mutation prevents the addition of the poly-A tail to a pre-mRNA molecule. What is the most likely effect on the mRNA?

Accepted Answer

The mRNA will be more susceptible to degradation by hydrolytic enzymes.

Question 6

Which of the following best explains why the number of proteins produced by humans exceeds the number of genes?

Accepted Answer

Alternative RNA splicing allows different combinations of exons to be joined, producing multiple proteins from one gene.

Question 7

What is the function of the spliceosome during RNA processing?

Accepted Answer

It removes introns and joins exons together in pre-mRNA.

Question 8

Which property of RNA allows ribozymes to catalyze reactions?

Accepted Answer

RNA can form complex three-dimensional structures, has functional groups for catalysis, and can base-pair with other nucleic acids.

Question 9

If a chemical agent removed the 5′ cap from all mRNAs in a cell, what would be the most immediate effect?

Accepted Answer

mRNAs would be more rapidly degraded and less efficiently translated.

Question 10

Which of the following is NOT a function of the untranslated regions (UTRs) of mRNA?

Accepted Answer

They are translated into amino acid sequences.

Question 11

A researcher discovers a eukaryotic gene with a very large number of introns. What is a likely advantage of this gene structure?

Accepted Answer

It allows for alternative splicing, increasing protein diversity.

Question 12

Which of the following best describes a ribozyme?

Accepted Answer

An RNA molecule that functions as an enzyme.

Question 13

In the analogy of watching a pre-recorded TV show, what do introns correspond to?

Accepted Answer

The commercials that are skipped during playback.

Question 14

Which of the following steps occurs LAST during the processing of a eukaryotic pre-mRNA?

Accepted Answer

Splicing out of introns and joining of exons.

Question 15

A mutation in the spliceosome's small RNAs prevents them from base-pairing with pre-mRNA. What is the most likely result?

Accepted Answer

Introns will not be accurately removed, leading to faulty mRNA.

Question 16

Which of the following is a direct result of the presence of introns in eukaryotic genes?

Accepted Answer

A single gene can produce multiple protein variants through alternative splicing.

Eukaryotic RNA Processing: Modifications and Splicing

Study Guide - Practice Questions