Carbohydrates: Sugars

Carbohydrates: Sugars
Sugars, important in nutrition, consist of monosaccharides, having the general formula C6H12O6, and disaccharides, having the general formula C12H22O11.

Although the monosaccharides consists of 3-carbon sugars (trioses), 4 carbon sugars (tetroses), 5-carbon sugars (pentoses), and 6-carbon sugars (hexoses), only the latter are important in human nutrition as sources of energy.

Glucose, a 6-carbon sugar, is one of the simplest carbohydrates found in foods. While many foods contain traces of glucose, it is found in significant amounts only in fruits, such as grapes. Fructose, also a 6-carbon sugar, is found in fruits and honey. Both of these sugars can be utilized by the body as a source of energy.

Sucrose (the ordinary table sugar derived from sugar and beets) is a 12-carbon sugar that is broken down in the intestine to glucose and fructose, hence utilized as a source of energy.

Lactose, the 12-carbon sugar present in milk, is broken down in the intestine to glucose and galactose (6-carbon sugars), both of which can be used as sources of energy.
Carbohydrates: Sugars