Monosaccharides or simple sugar consist of a single polyhydroxy aldehyde or ketone unit. The most abundant monosaccharide is the six- carbon sugar D- glucose. The word "monosaccharide" came from Greek Manos, or single, and sacchar, sugar. A commonly used monosaccharide is glucose which is found in the blood and monosaccharides are expressed by its chemical makeup as C6(H2O)6.
The carbon skeleton of monosaccharide is unbranched, and each carbon atom except one contains a hydroxyl group; at the remaining carbon atom there is carbonyl oxygen. Monosaccharides are classified as aldehyde or ketone depending on type of carbonyl group it contains. An aldehyde (-CHO) has a carbon bonded between hydrogen and oxygen, while a ketone (-CO-) has a carbon bond between carbon and oxygen.
Monosaccharides differ from disaccharides and polysaccharides by the number of rings the chemical compound has. A monosaccharide has a single ringed carbohydrate, while disaccharides like sucrose, also known as table sugar has two rings. Monosaccharides are joined together to form a disaccharide by glycosidic bond.
Sucrose is formed by the bonding of fructose and glucose. Polysaccharides are made of many monosaccharides joined together. Monosaccharides are also classified based on carbon atoms they have: Triose- 3, Tetrose- 4, Pentose- 5, Hexose- 6, Heptose- 7, Octose-8, Nonose- 9, and Decose- 10. The well known example glucose is hexose monosaccharide which has six carbon atoms.
There are about 20 types of monosaccharides that occur naturally, where the most well-known examples are glucose, fructose, and galactose.
Monosaccharides are absorbed through the walls of the intestine into the body, where it is passed into the bloodstream and are stored to be used as energy later on. On prolonged storage of monosaccharides leads to certain groups like fructose converted into fat. Most carbohydrates pass through the liver and that organ decides whether to store or burn the product. Results of studies showed that fructose alone bypassed the liver and went immediately into the metabolism and was burned. Whichever was not burned immediately turned to glycogen, a type of body fat.