Monosaccharides (from
Greek : single,
sacchar: sugar), also called
simple sugars, are the most basic units of
carbohydrates. They are fundamental units of carbohydrates and cannot be further hydrolised to simpler compounds. The general formula is where
n is 1, 2, 3 ... . 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.