Given below are four statements regarding amino acids: I. Isoleucine and Threonine are the only standard amino acids containing two chiral carbon atoms. II. Arginine is the most basic amino acid due to the presence of a guanidino group. III. Tyrosine is classified as an acidic amino acid because it contains a phenolic - OH group. IV. Tryptophan contains an indole ring and is classified as a non-essential amino acid.

Step-by-step solution

Statement I is correct. Among the 20 standard amino acids, only Isoleucine and Threonine have a chiral side chain, giving them two chiral centres in total. Statement II is correct. Arginine contains a guanidino group, which is highly resonance-stabilised upon protonation, making it the most basic amino acid. Statement III is incorrect. Although Tyrosine contains a weakly acidic phenolic - OH group, it is classified as a neutral amino acid because it contains an equal number of amino and carboxyl groups (one of each