PolysaccharidesPolysaccharides are polymers composed of several subunits of monosaccharides (simple sugars). They are formed by condensation reaction, in the same way as disaccharides are formed, the difference lies in the greater number of monomer units that compose them. The number of monosaccharides making up the chain is variable, and there are two types of chains that can form: branched or unbranched. The chains can be folded, making them compact and therefore ideal for storage. The size of the molecule makes them hydrophobic (insoluble), which is another characteristic that makes them ideal for storage, as they exert no osmotic influence and do not easily diffuse out of the cell. If subjected to the hydrolysis process, polysaccharides can be converted into their constituent monosaccharides, ready for use as respiratory substrates. Examples of storage polysaccharides are starch and glycogen. Starch: Starch is a mixture of two types of polymers: glucose, amylose and amylopectin. In amylose, the glucose units are linked by a linear succession of (1 => 4) glycosidic bonds. Amylose chain lengths vary within a single sample, but more than 1,000 glucose units are present per amylose molecule. The formula masses vary from 150,000 to 600,000. These molecules are found in the form of large grains, located inside the chloroplasts and in the storage organs. They are visible under an optical microscope. The long amylose molecules coil into spiral-shaped helices, which fold a significant fraction of the OH groups in and away from contact with water. Thus, amylose is only slightly soluble in water. Amylopectin molecules have both (1 => 4) and (1 => 6) glycosidic bonds. Bridges (1 => 6) connect the C-1 ends of the linear amylose type to C-6 positions of the glycose units in other long amylose chains. There are hundreds of such bonds per molecule, so amylopectin is highly branched and the branches prevent any winding of the polymer. This leaves many more OH groups exposed to water than in amylose, so