In which process unusual nucleotide (methyl guanosine triphosphate) is added to the 5' end of hnRNA?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Capping
Option (1) Splicing — Incorrect. In splicing the introns are removed and the exons joined.
Option (2) Capping — Correct. Adding methyl guanosine triphosphate to the 5′ end is capping. Tailing works at the other (3′) end, and splicing removes introns.
Option (3) Tailing — Incorrect. In tailing, 200–300 adenylate residues are added at the 3' end.
Option (4) Transcription factor — Incorrect. A transcription factor is a protein that helps RNA polymerase start transcription; it is not a processing step.
NCERT Extract:
Types of RNA and the Process of Transcription – “… (ii) The second complexity is that the primary transcripts contain both the exons and the introns and are non-functional. Hence, it is subjected to a process called splicing where the introns are removed and exons are joined in a defined order. hnRNA undergoes additional processing called as capping and tailing. In capping an unusual nucleotide (methyl guanosine triphosphate) is added to the 5’-end of hnRNA.”