Polysaccharides:- Polysaccharides are the naturally occurring condensation polymers in which large number of monosaccharides unit are joined together through glycoside linkages. They are colorless, tasteless (non sugars) substances and play an important role in plant and animal life. The two important polysaccharides are Starch and Cellulose.

(i) Starch:- It is the most important source of carbohydrate in human diet. It is food reserve material of plants and occurs mainly in seeds, fruits, tubers and roots of plants. General formula (C₆H₁₀O₅)_n.

Starch is a polymer of α-D-Glucose. It consists of two compounds:-

(a) Amylose:- Water soluble fraction and a linear polymer of α-D-Glucose. (C₁ – C₄ linkage).

(b) Amylopectin:- It is water insoluble fraction and consists of liner as well as branched chain polymers of α-D-Glucose. (C₁ – C₆ linkage).

(ii) Cellulose:- It is the chief structural material of cell walls of all the plants. It is also the chief structural material of cotton, wood and jute. It is a liner polymer of β-D-Glucose. (C₁ – C₄ linkage).