Question

An mRNA as it leaves the nucleus will have what on its 3' end?

A) polyA tail

B) exon

C) guanine cap

D) intron

E) AUG codon

Answer 1

Here the correct option is A) poly A tail.

Explanation -

After the transcription process the hnRNA (heteronuclear RNA) is produced. This RNA undergoes there types of processing to form mRNA. These processing are addition of cap at 5' end, exon splicing and polyadenylation at 3' end.

Polyadenylation or poly A tail is the addition of many adenosine monophosphate to the 3' end of the hnRNA. This process is catalysed by poly A polymerase enzyme. The poly A tail prevents the degradation of the mRNA.