The initial event in the conversion of an hnRNA to the mature RNA which leaves the nucleus is:
A) formation of ribonucleoprotein particles (RNPs).
B) capping the 5'-end of the transcript with a guanylyl group by guanylyl transferase.
C) addition of a poly(A) tail to the 3'-end of the transcript by poly(A) polymerase.
D) splicing together of the exons.
E) transesterification reactions in lariat formation.

Question

Quizplus · Accepted Answer

The first step in the conversion of hnRNA to mature RNA is the addition of a 7-methylguanylate cap to the 5'-end of the transcript by guanylyl transferase. This cap protects the RNA from degradation and facilitates its export from the nucleus.

The Initial Event in the Conversion of an HnRNA to the Mature