Carbohydrates

Glucose is a monosaccarie ( a simple sugar unit) C6 H12 O6

When two glucose molecules react together, the reaction is called condensation. Maltose (a dissaccharide) and water are formed in the reaction.  

A covalent bond is formed between two sugar units (disaccharides). Covalent bonds between sugar units are often referred to a glycosydic links.

Maltose splits into two glucose units when it undergoes a hydrolysis reaction with water.

Maltose is formed when glucose bonds with glucose, and sucrose is formed when glucose bonds with fructose. When lactose is formed by glucose bonding with galactose, the glycosidic links forms between different OH groups.

Sugar units build up by condensation into complex carbohydrates. Monosaccharides can be joined to form:

dissaccharides: 2 units

Oligosaccharides: 3-10 units

polysaccharides

Starch is a polymer made up of glucose monomers. It is a ploysaccharide made up of monosaccharides linked together. Starch is a storage ploysaccharide found in green plants.

Starch is made up of two polymers of glucose: anylose and amylopectin. Amylase is a chain of many thousands of glucose units. The glucose chain coils into a helix due to hydrogen bonding between OH groups. The general formula for a carbohydrate is given here as the simple formula because there is not a set number of glucose units in a molecule

Amylopectin is a branched chain of glucose molecules. The molecule contains many thousands of glucose units so the general formula for a glucose molecule is given here.

Glycogen is the storage polysaccharide found in animals and some microorganisms.