<prompt> Disulfide bonds are formed in which amino acid:GlycineCysteineProlineIsoleucine  <response>: Ans. b Cysteine -SH group of 2 cysteine in proteins can be oxidized to form a covalent disulfide bond. It significantly stabilizes tertiary structures of protein This bond plays crucial role in structures of many proteins by forming covalent links. Amino acid that decreases ageing process: Cysteine and Taurine Amino acid that accelerate ageing: Homocysteine 