Question

Which of the following statements is CORRECT?

a
Primary RNA transcript is processed to a mature RNA ONLY via 5'-capping and 3'- polyadenylation.
b
Diversity of mRNA molecules from a pre-mRNA occurs due to alternative splicing events.
c
In eukaryotic transcription, the Sigma factor distorts the DNA to enable recruitment of RNA polymerase
d
In prokaryotic transcription, TFIIH is responsible for phosphorylation the tail of RNA polymerase.

Answer 1

The correct statement is that the diversity of mRNA molecules from a pre-mRNA occurs due to alternative splicing events. The primary RNA transcript in eukaryotes is processed by 5'-capping, 3'-polyadenylation, and also by splicing.

Step-by-step explanation:

The correct statement among the options provided is:

b

Diversity of

mRNA molecules

from a pre-mRNA occurs due to alternative

splicing events

.

Eukaryotic pre-mRNAs are modified with a 5' cap and a poly-A tail. These structures protect the mature mRNA from degradation and help export it from the nucleus. Additionally, pre-mRNAs undergo splicing in which introns are removed and exons are reconnected. Only finished mRNAs that have undergone 5' capping, 3' polyadenylation, and intron splicing are exported from the nucleus to the cytoplasm.

In contrast to the correct statement b, primary RNA transcript is not processed to a mature RNA only via 5'-capping and 3'- polyadenylation, but also by splicing. Furthermore, in eukaryotic transcription, it is not the Sigma factor but a series of transcription factors that enable the recruitment of RNA polymerase II. The Sigma factor is associated with prokaryotic transcription. Additionally, TFIIH is a transcription factor involved in eukaryotic transcription, not in prokaryotic transcription, and it plays a role in the phosphorylation of RNA polymerase II tail, which is necessary for transcription initiation.