mRNA Maturation Quiz

What is the process called in which introns are removed and exons are joined together in a pre-mRNA molecule?

• Translation

• Transcription

• Splicing

• Replication

Answer explanation

The correct process where introns are removed and exons are joined in pre-mRNA is called splicing.

Which of the following molecules is NOT involved in the splicing process of pre-mRNA? (whilst you might not know some of these, you should know what is NOT involved)

• snRNPs

• mRNA

• Spliceosome

• DNA polymerase

Answer explanation

DNA polymerase is not involved in the splicing process of pre-mRNA. The other molecules listed - snRNPs, mRNA, and Spliceosome - are all involved in the splicing process.

In the context of mRNA maturation, what are introns?

• The segments of a pre-mRNA that are spliced out and degraded

• The segments of a pre-mRNA that are retained and expressed

• Proteins that aid in the splicing process

• Enzymes that catalyze the addition of a 5' cap

Answer explanation

Introns are the segments of a pre-mRNA that are spliced out and degraded, not retained and expressed.

What is the purpose of RNA editing?

• To remove exons from the mRNA

• To alter the nucleotide sequence of mRNA after transcription

• To add a poly-A tail to the mRNA

• To splice introns from the pre-mRNA

Answer explanation

RNA editing purpose is to alter the nucleotide sequence of mRNA after transcription, not to remove exons, add a poly-A tail, or splice introns.

Which of the following is NOT a step in mRNA maturation? (Note except for the one that is not involved, all the others are).

• Addition of a 5' cap

• Addition of a poly-A tail

• DNA replication

• Splicing of introns

Answer explanation

DNA replication is not a step in mRNA maturation. The other options - addition of a 5' cap, addition of a poly-A tail, and splicing of introns - are all part of mRNA maturation.

What role does the poly-A tail play in mRNA maturation? (NIC but interesting and you should be able to deduce the answer)

• It marks the mRNA for degradation.

• It assists in the export of mRNA from the nucleus.

• It signals the start of transcription.

• It adds nucleotides to the 5' end of the mRNA.

Answer explanation

The poly-A tail assists in the export of mRNA from the nucleus, aiding in the maturation process.

Which of the following is true about the removal of introns during splicing? (NIC but you should be able to deduce the answer).

• It occurs after the mRNA has been exported to the cytoplasm.

• It is a random process that occurs differently in every cell.

• It requires ATP as an energy source.

• It is mediated by ribosomes.

Answer explanation

The correct answer is that the removal of introns during splicing requires ATP as an energy source.