<Tr> <Td> </Td> <Td> This article only describes one highly specialized aspect of its associated subject . Please help improve this article by adding more general information . The talk page may contain suggestions . (September 2013) </Td> </Tr> <P> Monosaccharides (/ ˌmɒnoʊˈsækəraɪd, ˌmɒnə - /, from Greek monos: single, sacchar: sugar), also called simple sugars, are the most basic units of carbohydrates . They are fundamental units of carbohydrates and cannot be further hydrolyzed to simpler compounds . The general formula is C O . They are the simplest form of sugar and are usually colorless, water - soluble, and crystalline solids . Some monosaccharides have a sweet taste . Examples of monosaccharides include glucose (dextrose), fructose (levulose), and galactose . Monosaccharides are the building blocks of disaccharides (such as sucrose and lactose) and polysaccharides (such as cellulose and starch). Further, each carbon atom that supports a hydroxyl group (so, all of the carbons except for the primary and terminal carbon) is chiral, giving rise to a number of isomeric forms, all with the same chemical formula . For instance, galactose and glucose are both aldohexoses, but have different physical structures and chemical properties . </P> <P> With few exceptions (e.g., deoxyribose), monosaccharide have this chemical formula: C (H O), where conventionally x ≥ 3 . Monosaccharides can be classified by the number x of carbon atoms they contain: triose (3), tetrose (4), pentose (5), hexose (6), heptose (7), and so on . </P> <P> The most important monosaccharide, glucose, is a hexose . Examples of heptoses include the ketoses, mannoheptulose and sedoheptulose . Monosaccharides with eight or more carbons are rarely observed as they are quite unstable . In aqueous solutions monosaccharides exist as rings if they have more than four carbons . </P>

The minimum number of carbon in a monosaccharide is