Carbohydrates are the most abundant organic compounds in the plant world. The simpler members of the carbohydrate family are often referred to as saccharides because of their sweet taste. Saccharum in Latin mean ‘sugar’.
Monosaccharides are, as the name implies, the simplest of the carbohydrate and cannot be broken into smaller molecules of other carbohydrates.
Monosaccharides have a general formula Cx(H2O)y with one of the carbons being the carbonyl group of either an aldehyde or a ketone. Therefore, monosaccharides can be a polyhydroxy aldehyde or a polyhydroxy ketone.
The most common monosaccharides have three to nine carbon atoms.
The three most common monosaccharides are glucose, fructose and galactose.
Glucose
Glucose is a natural sugar found in food and also produced in the body form other simple and complex carbohydrates. Glucose containing six carbons that is present in the blood, also known as dextrose or blood sugar.
Fructose
Fructose or fruit sugar occurs naturally in fruits and honey and is converted to glucose in the body. It is often added to foods in the forms of high-fructose corn syrup. It is also called levulose or fruit sugar.
Galactose
Galactose is produced from milk sugar in the mammary glands of lactating animals and is converted to glucose in the body.
All other carbohydrates are made up of monosaccharides linked together. For instance, disaccharides are composed of two monosaccharides linked together.
A molecule of lactose, the sugar found in milk is made of two monosaccharides, galactose and glucose. Both sucrose and lactose are disaccharides.
When a large number of monosaccharides are linked together as in a molecule of starch, the result is called polysaccharide.
Monosaccharides: the basic unit of carbohydrates
