BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The pyrimidines (cytosine, uracil, and thymine) only have one single ring, which has just six members and two nitrogen atoms. Because purines are essentially pyrimidines fused with a second ring, they are obviously bigger than pyrimidines.

Detailed explanation-2: -A pyrimidine is a simple aromatic ring composed of six atoms, two nitrogen atoms and four carbon atoms. These are connected with alternating single and double bonds, creating very stable resonance structures. The structure is similar to a benzene ring.

Detailed explanation-3: -Art Connection. The purines have a double ring structure with a six-membered ring fused to a five-membered ring. Pyrimidines are smaller in size; they have a single six-membered ring structure. The images above illustrate the five bases of DNA and RNA.

Detailed explanation-4: -So here we can see that adenine and guanine with their two ring structures are the purines, and cytosine, thymine, uracil with the one ring structure are the pyrimidines.