Describe the process of transcription of mRNA in an Eukaryotic cell.

Explanation

RNA polymerase I transcribes rRNAs (26S, 18S and 5.8S)
RNA polymerase II transcribes the precursor of mRNA (called as heterogeneous nuclear RNA (hn RNA)) and RNA-polymerase III catalyses transcription of RNA.
(4) The primary transcript contains both exons and introns and it is subjected to a process called splicing, where the introns are removed and the exons are joined in a definite order to form mRNA
(5) The hnRNA undergoes two additional processes called 'capping' and 'tailing'. (6) In capping, methyl guanosine triphosphate is added to the S' end of hnRNA.
(7) In tailing, adenylate residues (about 200-300) are added at the 3' end of hnRNA.
(8) The fully processed hnRNA is called mRNA and is released from the nucleus into the cytoplasm.