Disaccharide is formed by two monosaccharides through glycosidic bonds and can be hydrolyzed into two monosaccharides, such as sucrose and maltose; Polysaccharide is formed by multiple monosaccharides through glycosidic bonds and can be hydrolyzed into multiple monosaccharides, such as starch and cellulose. Monosaccharide refers to carbohydrates that cannot be hydrolyzed again, such as glucose and fructose.