What are essential and non-essential amino acids? Give two examples of each type.
$$\alpha-$$ Amino acids which are needed for health and growth of human beings but are not synthesised by the human body are called essential amino acids. For examples, valine, leucine, phenylalanine, etc.
On the other hand, $$\alpha-$$ amino acids which are needed for health and growth of human beings and are synthesised by the human body are called non-essential amino acids. For examples, glycine, alanine aspartic acid, etc.