Question

Draw a neat and labelled diagram of transcription and processing of hn-RNA

Explain processing of hn-RNA with the help of neat and labelled diagram.

Answer 1

Answer 2

1. In eukaryotes, forms of RNA transcribed from DNA are called primary transcripts. Such transcripts undergo changes called processing or maturation before becoming functional.
2. The primary transcript is non-functional and contains both exons and introns.
3. During processing, only introns are removed by the process called splicing.
4. Exons are joined in a definite sequence (order) by the DNA ligase enzyme.
5. Heterogeneous nuclear RNA undergoes the process of capping and tailing.
6. In capping, methylated guanosine triphosphate is added to the 5’ end of hnRNA.
7. In tailing, polyadenylation (addition of multiple adenine nitrogen bases) takes place at 3’end.
8. It is the fully processed hnRNA, now called m-RNA.