A polysaccharide is a type of carbohydrate made up of long chains of sugar molecules. These complex carbohydrates can consist of hundreds or thousands of monosaccharide units linked together. Common examples include starch, glycogen, and cellulose, which serve various functions in living organisms, such as energy storage and structural support. Polysaccharides are classified into two main categories: storage polysaccharides and structural polysaccharides. Storage polysaccharides, like starch in plants and glycogen in animals, provide energy reserves. In contrast, structural polysaccharides, such as cellulose in plant cell walls, help maintain the integrity and rigidity of cells.