Carbohydrates Aldehyde • A functional group containing a carbon atom bonded to a hydrogen atom and doublebonded to an oxygen atom. Ketone • A carbon atom double bonded to an oxygen atom and bonded to two other carbon atoms. Carbohydrate • An aldehyde or ketone with hydroxyl groups (OH) added. • They form sugars and starches. • The most common energy source for cells. • Many take the form Cn(H2O)n Monosaccharides • Simple sugars • Most are sweet, colorless, dissolve in water and form crystals. • They have twice as many hydrogen atoms as oxygen atoms. Glucose • • • • • Also known as dextrose C6H12O6 The major food source for most cells. Produced by plants by photosynthesis The molecule is small enough that it does not need to be digested by humans. Fructose • Has the same formula as glucose (C6H12O6) but the atoms are arranged differently. • Found in honey, corn syrup , sweet potatoes and beets. • The sweetest of all natural sugars Disaccharides • Double sugars • Made by combining two monosaccharides with the loss of a water molecule. • Tend to feel sticky. Sucrose • Table sugar C12H22O11 • Made by combining glucose and fructose. • Made by plants including sugar cane, beets, sorghum and maple trees. • The main sugar used in cooking. Lactose • Milk sugar • Same formula as sucrose (C12H22O11) but has different structure. • Made from glucose and glactose. • About 70% of humans can’t digest lactose(lactose intolerance). Polysaccharides • Large molecules made by combining a string of monosacchrides. • Most have at least 200 carbon atoms. • Include starches, glycogen and cellulose. Starch • • • • • (C6H10O5)n The main molecules used by plants to store energy. No taste, doesn’t dissolve in water. Main food source for humans. Used to make glues. Glycogen • • • • The animal equivalent of starch. Used to store energy in animals Mainly found in the liver. Made by combining about 60,000 glucose molecules. Cellulose • • • • • Made up of about 10,000 glucose molecules. Forms the cell walls of plants Doesn’t dissolve in water. Can’t be digested by most animals. Used to make paper, rayon fibers and cellophane.