All of the following are essential aminoacids except:: (A) Methionine, (B) Lysine, (C) Alanine, (D) Leucine
Answer is C. Threonine, Lysine, Phenylalanine, Methionine, Isolcucine & Leucine, Tryptophan, Valine > Histidine >> Arginine are nutritionally essential amino acids. Among these last two (histidine & arginine) are semi- essential, and arginine is more essential than histidine.