1. Reserve food-materials. Some of the polysaccharides reserve food in animal and plant cells. The reserve food material in animals is glycogen whereas starch is of the plants.
2. Fuel. They are used as fuel. These polysaccharides are converted into monosaccharides and are oxidized for the release of energy.
3. Structural component. Some of the polysaccharides are structural component of the cells. For example some polysaccharides are involved in the formation of biomembranes. Cellulose and chitin are the main structural components.
4. Protective coat. Cell membrane made up of polysaccharides protects the cell.