Question

Amino acids behave like salts rather than simple amines or carboxylic acids. Explain.

Answer 1

Amino acids have acidic COOH group as well as $N{H}_2$ group hence, COOH looses its H to $N{H}_2$, hence they exist as Zwitter ion.
$R-\underset{Zwitlerion}{\underset{⨁}{\underset{N{H}_3}{\underset{|}{CH}}}}-COO{H}^{-}$