Question

During mRNA processing:

What is the primary action that occurs?
A) Adding a head and tailpiece
B) Removing introns (non-coding parts of the message)
C) Moving to the R______ (rRNA)

Choose the most appropriate action.

Answer 1

During mRNA processing, introns are removed, a 5' cap is added, and a 3' poly-A tail is attached to stabilize and prepare the pre-mRNA for translation into protein.

Step-by-step explanation:

Overview of mRNA Processing

During mRNA processing, the primary action is the removal of introns and the addition of a cap and tail to the pre-mRNA transcript. Initially, pre-mRNAs are coated with RNA-stabilizing proteins to prevent their degradation. The key steps in mRNA processing include the addition of a 5' cap and a 3' poly-A tail, as well as the splicing of mRNA to remove the non-coding sequences, known as introns, leaving only coding sequences or exons that are reconnected to form the final mRNA.

These modifications are crucial for the mRNA's stability, nuclear export, and translation into protein. The 5' cap helps initiate translation by ribosomes, and the 3' poly-A tail protects the mRNA molecule from degradation. Splicing ensures that only the necessary coding information contained within exons is expressed in the final protein product, allowing a single gene to encode multiple protein variants through alternative splicing.