Which of the following is an amino acid?

Options

A. `H_(2) NCOCOOH`
B. `CH_(3)underset(CONH_(2))underset(|)(C )HCOOH`
C. `H_(2)NCOOH`
D.

Answer

D

Explanation

Amino acids contain amino `(-NH_(2))` and carboxyl `(-COOH)` functional groups. Depending upon the relative position of amino group with respect to carboxyl group, the amino acid can be classified as `alpha, beta, gamma ,delta` and so on. Only `alpha`-amino acids. `H_(2)N - CH (R ) - CO_(2) H`, are obtained on hydrolysis of proteins. They may contain other functional groups also.
Compound (4) called proline is different from the other amino acids as it is `2^(@)` amine and also the amino `N` is part of a five - membered ring.