Amino acids are classified as acidic, basic or neutral depending upon the relative number of amino and carboxyl groups in their molecule. Which of the following are acidic amino acids?
(i) `(CH_3)_2 CH - underset(NH_2)underset(|) CH - COOH`
(ii) `HOOC - CH_2 - CH_2 - underset(NH_2)underset(|) CH - COOH`
(iii) ` H_2N - CH_2 - CH_2 - CH_2 - COOH`
(iv) `HOOC - CH_2 - underset(NH_2)underset(|) CH - COOH`

Options

A. (ii) and (iv)
B. (iii) and (iv)
C. (i) and (ii)
D. (ii) and (iii)

Answer

A

Explanation

Amino acids which contain one `-NH_2` group and two -COOH groups are acidic in nature.