Descrive the term D- and L-configuration used for amino acids with exmaples.

Explanation

All naturally occurring `alpha`-amino acids (except glycine) are optically active due to the presence of chiral carbon atom. These have either D- or L-configuration D-form means that, the amino `(-NH_(2))` group is present towards the right hand side L-atom shows the presence of `-NH_(2)` group on the left hand side.