BIOMOLECULES AND ENZYMES

Detailed explanation-1: -Amino acids are amphoteric compounds, as they contain both acidic (COOH) and basic (NH2) groups. They can react with both alkalies and acids to form salts. In acid solution amino acids carry positive charges and hence they move towards cathode in an electric field.

Detailed explanation-2: -Hence they behave as acids in an alkaline medium and bases in an acidic medium. So, amino acids are amphoteric.

Detailed explanation-3: -Amphoteric properties of a protein are due to the presence of free carboxylic and free amino group at the end of the protein which can react with the acids and bases. In acidic medium, protein carries positive charges at amino group and in the alkaline medium it carries negative charges at the carboxylic group.

Detailed explanation-4: -When an amino acid dissolves in water, the zwitterion interacts with H2O molecules – acting as both an acid and a base. But, unlike simple amphoteric compounds that may only form either a cationic or anionic species, a zwitterion simultaneously has both ionic states.