Question

The mechanism of removing introns followed by joining of the exons in a defined order during transcription is called

• A. Splicing
• B. Tailing
• C. Transformation
• D. Capping

Answer 1

The correct option is A Splicing

• The gene encoding for mRNA has two types of sequences called the introns and the exons. The introns are the intervening sequences and they do not code for a functional polypeptide.
• The exons are the functional sequences. However, the exons are intervened by the introns.
• When such a gene is transcribed, the RNA so formed will have both these sequences. Such an RNA is called the hnRNA (heterogeneous RNA) or the pre-mRNA.
• This pre-mRNA undergoes a post-transcriptional modification called splicing where these introns are removed from the pre-mRNA.
• The RNA obtained after the process of splicing is called the mRNA and it has the sequences for only exons, that will be translated to form a functional polypeptide.

Thus, the correct answer is (A).