Amino-acid substitute for tryptophan without altering proteins characteristics -

Ans. is 'b' i.e., Phenylalanine o Tryptophan is an aromatic amino acid, thus it can only be replaced with other aromatic amino acid, o Other two aromatic amino acids area)Phenylalanineb)Tyrosineo Among these two, phenylalanine can substitute tryptophan but not tyrosine because#Phenylalanine and tryptophan both are hydrophobic (non-polar).#Whereas, tyrosine is hydrophilic (Polar)."The only other aromatic residue that can substitute for tryptophan is phenylalanine. Tyrosine cannot substitute since it has hydrophilic property "