Question

Post-transcriptional processing adds a(n) ________ to the 5' end of the mRNA molecule.

A) poly A tail
B) exon
C) CAP
D) intron
E) poly C tail

Answer 1

In post-transcriptional processing, a 5' cap, specifically a 7-methylguanosine cap, is added to the mRNA molecule's 5' end to protect it and aid in translation initiation.

Step-by-step explanation:

Post-transcriptional processing adds a cap to the 5' end of the mRNA molecule. This cap is known as a 7-methylguanosine cap, or simply a 5' cap. This modification is crucial as it protects the mRNA from degradation and assists in the initiation of translation by ribosomes, making it an essential step in mRNA processing in eukaryotic cells.