Sugars are the simplest carbohydrates. The monosaccharides are "single sugars", such as glucose and fructose. The disaccharides are two monosaccharides joined together. Table sugar (cane sugar) is a disaccharide of glucose and fructose. The polysaccharides are made from many monosaccharids joined together. The vast majority of polysaccharides are polymers of glucose, and are of two types: starch and cellulose. Starch is the white stuff of grain, potatoes, apples, and bread, and is a readily available source of energy for the body. Cellulose is the structural material that holds up all plants. Half of the material that makes wood is cellulose.