Disaccharide

A disaccharide is a type of carbohydrate that is composed of two monosaccharide molecules bonded together. Disaccharides are an important class of sugars and are found in many foods. They are a type of oligosaccharide, which are carbohydrates that contain a small number of simple sugars.

Structure

Structure of sucrose, a common disaccharide.

Disaccharides are formed when two monosaccharides undergo a condensation reaction, which involves the removal of a water molecule. The bond that forms between the two sugar molecules is known as a glycosidic bond.

The most common disaccharides include:

• Sucrose
• Lactose
• Maltose

Sucrose

Sucrose is perhaps the most well-known disaccharide. It is composed of one molecule of glucose and one molecule of fructose. Sucrose is commonly known as table sugar and is found in many plants, particularly in sugar cane and sugar beets.

Function

Disaccharides serve various functions in living organisms. They are primarily used as a source of energy. When consumed, disaccharides are broken down into their monosaccharide components by enzymes in the digestive system. For example, the enzyme sucrase breaks down sucrose into glucose and fructose.

Related pages

• Monosaccharide
• Polysaccharide
• Carbohydrate
• Glycosidic bond