Why are starch and glycogen more suitable as storage product than glucose?

Starch and glycogen are both ways of storing glucose, the energy source for most cells. Starch and glycogen are both polymers of glucose, produced by repeated condensation reactions between glucose molecules. When the glucose is needed, they can be broken down by hydrolysis reactions to release the glucose. The advantages of storing glucose as a polymer are that it prevents the glucose from being used up in other reactions, by taking it out of solution, and it also prevents the glucose from altering the water balance of the cell. If large numbers of glucose molecules were produced they would draw water into the cell by osmosis. Similarly when they were used up water could leave the cell by osmosis. Polysaccharides are insoluble and so do not affect the water balance of the cell.