Question 1

Which of the following modifications is NOT typically found in mature eukaryotic mRNA?

Accepted Answer

Introns retained within the coding sequence

Question 2

What is the correct sequence of events during eukaryotic pre-mRNA processing?

Accepted Answer

5' capping, splicing, 3' polyadenylation

Question 3

Which enzyme is responsible for adding the guanine nucleotide during 5' capping of pre-mRNA?

Accepted Answer

Guanylyl transferase

Question 4

The polyadenylation signal sequence required for 3' end processing of pre-mRNA is:

Accepted Answer

$$5'	ext{-}AAUAAA	ext{-}3'$$

Question 5

Which of the following is a function of the 5' cap on eukaryotic mRNA?

Accepted Answer

All of the above

Question 6

During splicing, which sequence is found at the 5' end of most eukaryotic introns?

Accepted Answer

$$GU$$

Question 7

What is the role of the branch point adenine in the splicing reaction?

Accepted Answer

Its 2'-hydroxyl group attacks the 5' splice site, forming a lariat structure

Question 8

Which snRNP is the first to bind to the 5' splice site during spliceosome assembly?

Accepted Answer

U1

Question 9

The Torpedo Model of transcription termination involves:

Accepted Answer

A ribonuclease degrading the residual RNA after cleavage, causing RNA Pol II to dissociate

Question 10

Alternative splicing allows for:

Accepted Answer

The production of multiple protein isoforms from a single gene

Question 11

Which of the following statements about the coupling of pre-mRNA processing steps is TRUE?

Accepted Answer

The carboxyl terminal domain (CTD) of RNA Pol II coordinates the recruitment of processing enzymes during transcription

Question 12

A mutation that disrupts the GU dinucleotide at the 5' splice site would most likely result in:

Accepted Answer

Retention of the intron in the mature mRNA

Question 13

Which of the following is NOT a function of the poly(A) tail?

Accepted Answer

Initiates splicing of introns

Question 14

Which of the following best describes the difference between pre-mRNA and mature mRNA in eukaryotes?

Accepted Answer

Pre-mRNA contains both exons and introns, while mature mRNA contains only exons

Question 15

Which of the following is TRUE regarding group I introns?

Accepted Answer

They are self-splicing ribozymes

Question 16

A patient has a mutation that prevents methylation of the 5' cap. Which process is most likely to be affected?

Accepted Answer

Transport of mRNA out of the nucleus

Question 17

Which of the following best explains why eukaryotic cells can produce more proteins than the number of genes they contain?

Accepted Answer

Alternative pre-mRNA processing, including alternative splicing and polyadenylation

Question 18

In the context of RNA editing, what is the consequence of changing a cytosine to a uracil in the mRNA of the human apolipoprotein B gene?

Accepted Answer

It creates a new stop codon, resulting in a shorter protein

Question 19

Which of the following is a direct result of the Torpedo RNase activity during transcription termination?

Accepted Answer

Dissociation of RNA polymerase II from the DNA template

Question 20

Which of the following statements about alternative polyadenylation is correct?

Accepted Answer

It can result in mRNAs with different 3' ends from the same gene

Post-Transcriptional Processing and Splicing in Eukaryotic mRNA

Study Guide - Practice Questions