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

In aqueous solution,the carboxylic group $(-COOH)$ loses a proton $(H^+)$ and the amino group $(-NH_2)$ accepts a proton to form a dipolar ion known as a Zwitter ion.
The reaction is:
$R-CH(NH_2)-COOH \rightleftharpoons R-CH(NH_3^+)-COO^-$
Because of this internal salt-like structure,amino acids exhibit high melting points and solubility in water,similar to ionic salts.