Question

Amino acids may be acidic, alkaline or neutral. Justify the statement.

Answer 1

Amino acids have two types of groups:

—NH   basic

— COOH   acidic

Case I : In $\alpha$-amino acids like glycine, alanine, etc. there is formation of dipolar ion called zwitter ion.

In such case if $\mathrm{p} K_a\left(\right.$ acid) $=\mathrm{p} K_b$ (base) then amino acid shows neutral behaviour.

Case II : If in an amino acid, there are two basic parts and one acidic part it will show basic nature e.g., lysine.

Case III : If in an amino acid, there are two acidic parts and one basic part it will show acidic nature.

e.g., glutamic acid.