Question

In which part of the mRNA does degradation generally begin?

a) 5' UTR (Untranslated Region)
b) Start codon
c) Coding sequence
d) 3' UTR (Untranslated Region)

Answer 1

mRNA degradation generally begins at the 3' Untranslated Region (3' UTR), which influences mRNA stability and localization. Option number d is correct.

Step-by-step explanation:

The degradation of mRNA generally begins at the 3' Untranslated Region (3' UTR). mRNA molecules have structures that are critical to their stability and function: the 5' cap, the coding sequence, and the 3' poly-A tail.

The 3' UTR, located just downstream of the protein-coding region, plays a role in the regulation of gene expression by influencing mRNA stability and localization, and is often the initiating site for mRNA degradation. The presence of RNA-binding proteins at the 3' UTR can protect mRNA from degradation, but once these proteins are removed or if the poly-A tail is shortened, the mRNA becomes more susceptible to degradation.