They are classified as acidic (containing 2–COOH group), basic (containing 2NH2 group) i.e. NH2 is a basic group in Lysine.

What are group is present in glycine?

Like all of the amino acids, glycine has two functional groups, a carboxyl group (COOH) and an amine group (NH2).

Is glycine a base or acid?

The behavior of glycine is reasonably typical of that of the simplest amino acids. Because glycine is neither a strong acid nor a strong base, we shall expect a solution of glycine in water to contain four species in rapid equilibrium.