Carbohydrates

• Glucose's structure is related to its function as the main energy source in animals and plants. Its structure makes it soluble so it can be easily transported. Its chemical bonds contain a lot of energy.
• Ribose is a monosaccharide with five carbon atoms - this means its a pentose monosaccharide.
• All carbohydrates are made up of the same 3 chemical elements - carbon, hydrogen and oxygen. For every carbon atom there are usually two hydrogen and one oxygen atom.
• Monosaccharides are joined together by glycosidic bonds.
• During synthesis, a hydrogen atom on one monosaccharide bonds to the hydroxyl group on the other, releasing a molecule of water. This is called a condensation reaction.
• The reverse of this synthesis reaction is hydrolysis. A molecule of water reacts with the glycosidic bond, breaking it apart.
• A disaccharide is formed when two monosaccharides join together.
• Other disaccharides are formed in a similar way. Sucrose is a disaccharide formed when alpha-glucose and fructose join together. Lactose is a disaccharide formed by the joining together of either alpha-glucose or beta-glucose and galactose.
• A polysaccharide is formed when more than two monosaccharides join together. Lots of alpha-glucose molecules are joined together by glycosidic bonds to form amylose.