Carbohydrates

• Starch contains two types of molecules, amylose and amylopectin. Amylose is unbranched and composed of alpha glucose molecules linked together by alpha 1,4 glyosidic bonds. Amylopectin is composed of alpha glucose molecules linked together by alpha 1,4 and alpha 1,6 glyosidic bonds, which result in branching of the molecule.
• Cellulose is made up of beta-glucose units joined by beta 1,4 glycosidic bonds
• When two molecules of glucose are joined together by a condensation reaction maltose is formed and water is removed.
• Maltose is broken down into two molecules of glucose by a hydrolysis reaction, where water is added.
• Monosaccharides consist of only a single sugar molecule and are commonly called simple sugars. They are soluble in water due to the large number of hydroxyl groups. Glucose, fructose, and galactose, are examples of monosaccharides.
• A disaccharide contains two monosaccharides that have joined during a dehydration reaction. Maltose, sucrose and lactose are examples of disaccharides.
• Polysaccharides are long polymers of monosaccharides. Some types function as short-term energy storage molecules. Others are structural, and are involved in maintaining the structure of cells. they are not as soluble in water and therefore cannot easily pass through the plasma membrane. Examples include cellulose, starch, chitin, and peptidoglycan.