Two monosaccharide molecules are connected by glycosidic bonds. According to the Pacific Science and Technology Network, monosaccharide is the smallest sugar molecule and the basic structural unit of sugar. Common monosaccharides are glucose, fructose and galactose. When two monosaccharide molecules are linked together by glycosidic bonds, disaccharides are formed. Disaccharide is a kind of sugar composed of two monosaccharide molecules connected by glycosidic bonds. It is a common carbohydrate in organisms and an important component in many foods.