Describe the structure of a RNA polynucleotide chain having four different types of nucleotides.

Explanation

RNA nucleotide has three main components-a nitrogenous base, a ribose sugar and a phosphate group.
1. The ribose sugar and the phosphates form the backbone of a poly nucleotide chain with nitrogenous base linked to sugar moiety and projecting from the backbone.
2. Nitrogenous Bases-(i) purines (Adenine & Guanine) (ii) Pyrimidines- (Cytosine and Uracil)
3. Nitrogenous base is linked to the ribose sugar through N-glycosidic linkages.
4. Phosphate group is linked to 5' OH of a nucleoside through phosphate linkage to form a corresponding nucleotide.
5. Every nucleotide residue has an additional-OH group present at 2'-position in the ribose.
6. The end of the chain which has free phosphate moiety at 5 'end of ribose sugar is referred to as 5' end and the other end of the chain having a free 3'- OH group at the ribose sugar is referred to as 3' - end of the polynucleotide chain.