84.Tailing of hn RNA will occur by addition of A. Guanylate residues (200-300) B. Cytidylate residues (200-300) C. Adenylate residues (200-300) D. Thymidylate residues (200-300)
Option C. The primary mRNA transcript is longer and localized into the nucleus, where it is also called heterogeneous nuclear RNA (hnRNA) or pre-mRNA. At the 5 end of hnRNA, a cap (consisting of 7-methyl 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 mRNAs are made up of two types of segments; non-coding introns and the coding exons. The introns are removed by a process called RNA splicing and the exons are joined in a defined Order.
