Question

Write a short note on heterocyclic base present in nucleic acids. (structure is not required).

Answer 1

Nucleic acids are the third class of biopolymers others are polysaccharides and proteins.

Two major classes of nucleic acids are:

1. deoxyribonucleic acid (DNA): carrier of genetic information

2. ribonucleic acid (RNA): an intermediate in the expression of genetic information and other diverse roles

The monomeric units for nucleic acids are nucleotides. These are made up of three structural subunits:

1. Sugar: ribose in RNA, 2-deoxyribose in DNA

2. Heterocyclic base

3. Phosphate

The heterocyclic base are derivatives of Pyrimidines and Purines. Purine moiety is present in Adenine(A) and guanine (G). Pyrimidine moiety is present in cytosine (C), thymine (T) and Uracil(U). G, T and U exist in the keto form.