Flexi Says: Carbohydrate molecules contain atoms of carbon, hydrogen, and oxygen. Living things use carbohydrates mainly for energy. According to their structure they are classified as monosaccharides, disaccharides and polysaccharides. A monosaccharide is a simple sugar, such as fructose or glucose. If two monosaccharides bond together, they form a carbohydrate called a disaccharide like Sucrose. A polysaccharide is a complex carbohydrate that forms when simple sugars bind together in a chain. Starch and Cellulose are common complex carbohydrate that is a polymer of glucose.
