BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Answer and Explanation: The correct option is b. A fatty acid group.. The amino acid structure contains an amine group and a carboxylic group.

Detailed explanation-2: -There are basically four different classes of amino acids determined by different side chains: (1) non-polar and neutral, (2) polar and neutral, (3) acidic and polar, (4) basic and polar.

Detailed explanation-3: -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-4: -All amino acids have a general structure comprising of an alpha carbon atom, a carboxyl group, an amino group and a hydrogen atom. Therefore, from the options above, only A) Carboxyl functional group is present in all amino acids. Phosphate, methyl and ketone groups are not common in all amino acids.