Question

In eukaryotes, RNA polymerase II transcribes precursor of mRNA, called hnRNA.

1. What is the full form of hnRNA? 

2. Describe the additional processing takes place in an hnRNA to become mRNA.

3. What is gene splicing?

Answer 1

1. Heterogeneous nuclear RNA

2. The additional processing takes place in an hnRNA to become mRNA:

i. Capping:

It is the addition of nucleotide (methyl guanosine triphosphate) at 5¹ – end of hnRNA.

ii. Tailing:

It is the addition of adenylate residues at 3¹ – end.

3. Gene splicing is the removal of nonfunctional introns and joining of exons in a defined order.