BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Proline is unique among the standard amino acids in that it does not have both free -amino and free -carboxyl groups. Instead, its side chain forms a cyclic structure as the nitrogen atom of proline is linked to two carbon atoms.

Detailed explanation-2: -Like all of the amino acids, glycine has two functional groups, a carboxyl group (COOH) and an amine group (NH2). It has the simplest side chain of all of the amino acids, composed of a single hydrogen atom (-H).

Detailed explanation-3: -Although the keto group is the most versatile of the functional groups in organic chemistry, it is absent in the genetically encoded amino acids.