Question

Heterogeneous nuclear RNA is converted into mRNA by

• A. Tailing
• B. Splicing
• C. Capping
• D. All of the above

Answer 1

The correct option is D All of the above

Introduction to hnRNA
In eukaryotes, the primary RNA transcript is known as heterogeneous RNA or hnRNA. It undergoes chemical modifications such as capping, tailing and splicing, in the nucleus before being transported out into the cytoplasm for translation.

Splicing
Removal of introns (non-coding regions) and joining the exons (coding regions) of the RNA transcript in a defined order is known as splicing.

Capping
Addition of methyl guanosine triphosphate to the 5’ end of the hnRNA is known as capping.

Tailing
Tailing is the addition of $200-300$ adenylate residues to the 3’ end of the hnRNA.

Final answer
(D) All of the above