Starch consists of carbon, hydrogen and oxygen. Starch is formed from glucose monomers linked together with dehydration reactions, giving the formula (C6H10O5)n, where "n" is the number of glucose monomers bonded together.
Plants use starch to store extra glucose, which holds the energy needed for cellular respiration. Starch in plants is stored in granules and broken down as needed for energy. Photosynthesis generates the glucose used in starch, which is then polymerized through a dehydration reaction. The strength and length of starch molecules make starch an important component of many paper and paper-based products, including cardboard and boxes. Starch is insoluble in cold water and other solvents.