Monosaccharides, or simple sugars, can contain as few as three carbon atoms and are often used as building blocks to form larger molecules.
Disaccharides. Many familiar sugars like sucrose are “double sugars,” two monosaccharides joined by a covalent Bond.
Polysaccharides are macromolecules made up of monosaccharide subunits. Starch is a polysaccharide used by plants to store energy. It consists entirely of
glucose molecules, linked one after another in long chains.
Cellulose is a polysaccharide that serves as a structural building material in plants. It too consists entirely of glucose molecules linked together into chains, and special enzymes are required to break the links.