There are twenty amino acids and amides in the proteins. Plants are capable of synthesising all the proteins and amino acids. In animals several amino acids (10 number) are formed through transamination or transformation. Those amino acids, which cannot be synthesised by animals are considered as essential amino acids. So, they must be taken in diet. Some of these are leucine, isoleucine, valine, tryptophan, phenylalanine, lysine, methionine and threanine. Tryptophan deficiency cause mood and sleep deregulation. Having a deficiency in lysine can lead to niacin deficiency and lack of methionine leads to decreased production of sulphur in body