(a) Carbohydrates that give large number of monosaccharide units on hydrolysis / large number of monosaccharide units joined together by glycosidic linkage starch/ glycogen/ cellulose (or any other) (b) Proteins that lose their biological activity / proteins in which secondary and tertiary structures are destroyed Curdling of milk (or any other) (c) Amino acids which cannot be synthesised in the body. Valine/Leucine (or any other) OR (a) When D-glucose reacts with conc. $\mathrm{HNO}_3$, it forms saccharic acid. (b) In aqueous solution, the carboxyl group present in amino acid can lose a proton and the amino group can accept a proton to form zwitter ion. This zwitter ion can act both as an acid and a base showing amphoteric behaviour. $\mathrm{R} - \underset{\mathrm{NH}_2}{\underset{\vert}{\mathrm{CH}}} - \overset{\mathrm{O}}{\overset{\parallel}{\mathrm{C}}} - \mathrm{O}^{-}$ $\;\;\; \overset{H^{+}}{\underset{OH^{-}}{\rightleftharpoons}} \;\;\; \mathrm{R} - \underset{\mathrm{NH}_2}{\underset{\vert}{\mathrm{CH}}} - \overset{\mathrm{O}}{\overset{\parallel}{\mathrm{C}}} - \mathrm{O}^{-}$ $\;\;\; \overset{H^{+}}{\underset{OH^{-}}{\rightleftharpoons}} \;\;\; \mathrm{R} - \underset{^{+}\mathrm{NH}_2}{\underset{\vert}{\mathrm{CH}}} - \overset{\mathrm{O}}{\overset{\parallel}{\mathrm{C}}} - \mathrm{OH}$ (c) $\alpha$-helix has intramolecular hydrogen bonding while $\beta$ pleated has intermolecular hydrogen bonding / $\alpha$-helix results due to regular coiling of polypeptide chains while in $\beta$ pleated all polypeptide chains are stretched and arranged side by side.