BIOMOLECULES AND ENZYMES

Detailed explanation-1: -RNA consists of four nitrogenous bases : adenine, cytosine, uracil, and guanine. Uracil is a pyrimidine that is structurally similar to the thymine, another pyrimidine that is found in DNA. Like thymine, uracil can base-pair with adenine (Figure 2).

Detailed explanation-2: -Uracil is one of four nitrogenous bases found in the RNA molecule: uracil and cytosine (derived from pyrimidine) and adenine and guanine (derived from purine). Deoxyribonucleic acid (DNA) also contains each of these nitrogenous bases, except that thymine is substituted for uracil.

Detailed explanation-3: -The nitrogenous bases found in nucleotides are classified as pyrimidines or purines. Pyrimidines are heterocyclic amines with two nitrogen atoms in a six-member ring and include uracil, thymine, and cytosine.

Detailed explanation-4: -Three of the four nitrogenous bases that make up RNA-adenine (A), cytosine (C), and guanine (G)-are also found in DNA. In RNA, however, a base called uracil (U) replaces thymine (T) as the complementary nucleotide to adenine (Figure 3).

Detailed explanation-5: -The nitrogenous bases may form hydrogen bonds according to complementary base pairing: Adenine always forms two hydrogen bonds with thymine / uracil. Guanine always forms three hydrogen bonds with cytosine.