Question

What is meant by essential amino acids? Why are amino acids amphoteric in nature?

Hint:

Amino acids are amphoteric because of the presence of both acidic (COOH) and basic (NH$_2$) groups in their structure.

Answer 1

Essential amino acids are amino acids that cannot be synthesized by the body and must be obtained through the diet. These include leucine, valine, and lysine.
Amino acids are amphoteric in nature because they contain both an amino group (-NH$_2$) and a carboxyl group (-COOH). The amino group can act as a base (accepting a proton), and the carboxyl group can act as an acid (donating a proton). This dual nature allows amino acids to act as both acids and bases depending on the pH of the environment.