`alpha -` Amino acids which are needed for good health and proper growth of human beings but are not synthesized by the human body are called -essential amino acids. For example, valine, leucine, phenylalanine, etc. On the other hand, `alpha`-amino acids which are needed for health and growth of human beings and are synthesized by the human body are called non-essential amino acids. For example, glycine, alanine, aspartic acid etc.
