Question

Describe the process of synthesis of fully functional $mRNA$ in a eukaryotic cell.

Answer 1

a) Mature mRNA is formed from hnRNA by following process:

• Splicing: In this step all the introns are removed and exons are joined by the ligase enzymne.
• Capping: In this step methyl guanosine triphosphate is added to the 5' end of hnRNA like a cap.
• Tailing: In this step 200-300 adenylate residuse are added to the 3' end of hnRNA and form tail of adenine to prevent the ligation of 3' end and 5' aend of RNA.

b) In prokaryotes structure genes are polycistronic and continues and thus it does not need splicing to form mRNA.

Whereas in eukaryotes hnRNA is formed which contains coding and non coding region and needs to remove non coding region by splicing to form mature mRNA.