A. Arginine and Tryptophan are essential amino acids - True
B. Histidine contains imidazole ring (heterocyclic ring with N) - Statement is False
C. Proline has a 5-membered pyrrolidine ring, not 6-membered - False
D. Glycine (NH2−CH2−COOH) has no chiral center (α-carbon has two H atoms) - True
E. Cysteine side chain is −CH2−SH (thiol). MeS−CH2−CH2− is the side chain of Methionine, not Cysteine - False
Correct statements: A and D only