Nitrogen is an essential constituent of all

Assertion : Carboxypeptidase is an exopeptidase.
Reason : It cleaves the $N$-terminal bond.

Which among the following compounds contains both,amino and carboxyl groups in it?

The structure of a peptide is given below. If the absolute values of the net charge of the peptide at $pH = 2$,$pH = 6$,and $pH = 11$ are $|z_1|$,$|z_2|$,and $|z_3|$,respectively,then what is $|z_1| + |z_2| + |z_3|$?

Which amino acid is not optically active?

Which amino acid from the following is $NOT$ synthesized in our body?