Question

a) Which of the following is a polysaccharide?

i) Maltose

ii) Sucrose

iii) Fructose

iv) Cellulose

b) Explain the amphoteric behaviour of amino acid.

Answer 1

a) iv) Cellulose

b) This behaviour is due to the presence of both acidic (carboxyl group) and basic (amino group) groups in the same molecule. In aqueous solution, the carboxyl group can lose a proton and amino group can accept a proton, giving rise to a dipolar ion known as a zwitterion. In zwitterionic form, aminoacids show amphoteric behaviour as they react both with acids and bases.