Biomolecules Part 1

Biuret test produces violet colour on addition of dilute CaSO4 to alkaline solution of a compound containing peptide linkage.
Polypeptides, proteins and urea have -
−

C

|| O

−NH−
(peptide) linkage while carbohydrates have glycosidic linkages. So, test of carbohydrates should be different from that of other three.