Select the correct statements regarding the process of transcription in eukaryotes.
(i) The strand of dsDNA which takes part in transcription process is called as coding strand.
(ii) The enzyme RNA polymerase can catalyse polymerisation only in one direction i.e. ,`5' rarr 3'` .
(iii) An unusual nucleotide methyl guanosine triphosphate is added to the 5' end of hnRNA during capping.
(iv) During tailing process, adenylate residues (200-300) are added at 3' end in a template independent manner.

Options

A. (i) and (ii)
B. (iii) and (iv)
C. (ii),(iii) and (iv)
D. (i),(ii),(iii) and (iv)

Answer

c

Explanation

(c) : The primary mRNA transcript is longer and localised into the nucleus , where it is also called heterogenous nuclear RNA (hnRNA) or pre-mRNA. At the 5' end of hnRNA, a cap (consisting of 7-emthyl guanosine triphosphate or 7 mG) and a tail of poly A (Adenylate residues) at the 3' end are added. These processes are respectively called as capping and tailing. The cap is a chemically modified molecule of guanosine triphosphate (GTP) . The primary mRNA are made up of two types of segments, non-coding nitrons and the coding exons. The introns are removed by a proces called RNA splicing and the exons are joined in a defined order .