Question

After transcription begins, several steps must be completed before the fully processed mRNA is ready to be used as a template for protein synthesis on the ribosomes. Which three statements correctly describe the processing that takes place before a mature mRNA exits the nucleus?

Answer 1

Answer:

Poly-A tailing at 3' end

Capping at 5 ' end

Removal of Introns

Explanation:

Post transcription processing includes

1. Poly-A Tailing at 3'end: The 3'end terminus is polyadenlated in the nucleoplasm. This poly-A tail may be from 20-250 nucleotide long. This tail protects mRNA from attack by 3'exonuclease.

2. Capping at 5' end: Eukaryotic mRNAs are all capped at the 5' terminus by 7-methyl guanosine triphosphate. This occur in the nucleus.

3. Removal of Introns: the primary transcript contains coding region (exons) and non coding region (Introns). They intron are cleaved and exons are spliced. This is also done in the nucleus.