<prompt> Collagen contains amino acids Proline, Lysine and:GlycineIsoleucineCysteineMethionine  <response>: Ans. a GlycineGlycine In collagen every third amino acid is glycine Glycine is considered as the simplest amino acid Properties of glycine: Non-essential, Glucogenic and optically inactive amino acid Acts as a conjugating agent: Conjugation of benzoic acid Conjugation of bile acid As neurotransmitter, it has both properties excitatory and inhibitory.Other amino acids present in collagen are: Proline, Hydroxyproline, Hydroxylysine Lysine K An essential amino acid which is predominantly ketogenic It is an amino acid which is deficient in cereals Functions: Important for covalent cross linkingin collagen Precursor of carnitine Lysine Methionine 