1. 1 16.1 Types of Carbohydrates 16.2 Classification of Monosaccharides 16.3 D and L Notations from Fischer Projections 16.4 Structures of Some Important Monosaccharides Chapter 16 Carbohydrates

2. 2 Carbohydrates Carbohydrates are: A major source of energy from our diet. Composed of the elements C, H and O. Also called saccharides, which means “sugars.” Produced by photosynthesis in plants.

3. 3 Photosynthesis and Respiration Photosynthesis in plants requires CO 2, H 2 O, and energy from the sun and produces carbohydrates, such as glucose [C 6 H 12 O 6 =C(H 2 O) 6 ]. In respiration, glucose is oxidized in living cells to produce CO 2, H 2 O, and energy.

4. 4 Types of Carbohydrates  Monosaccharides are the simplest carbohydrates.  Disaccharides consist of two monosaccharides.  Polysaccharides contain many monosaccharides.

5. 5 Classification of Monosaccharides Aldoses are monosaccharides with an aldehyde group and many hydroxyl (-OH) groups. Ketoses are monosaccharides with a ketone group and many hydroxyl (-OH) groups. Aldose Aldose Ketose

6. 6 Monosaccharides Monosaccharides are also classified according to the number of carbon atoms. A triose has three carbons; a tetrose has four carbons; a pentose has five carbons; and a hexose has six carbons. triose tetrose hexose

7. 7 Fischer Projections A Fischer projection Is used to represent carbohydrates. Places the most oxidized group at the top. Uses horizontal lines for bonds that come forward. Uses vertical lines for bonds that go back.

8. 8 D and L Notations By convention, the letter L is assigned to the structure with the —OH on the left. The letter D is assigned to the structure with —OH on the right.

9. 9 D and L Monosaccharides The —OH on the chiral atom farthest from the carbonyl group is used to assign the D or L configuration.

10. 10 D-Glucose D-Glucose is: Found in fruits, corn syrup, and honey. An aldohexose with the formula C 6 H 12 O 6. Known as blood sugar in the body.

11. 11 Blood Glucose Level In the body, glucose has a normal concentration of 70-90 mg/dL. In a glucose tolerance test, blood glucose is measured for several hours after ingesting glucose.

12. 12 D-Fructose D-Fructose: Is a ketohexose C 6 H 12 O 6. Is the sweetest carbohydrate. Is found in fruit juices and honey. Converts to glucose in the body.

13. 13 D-Galactose D-Galactose: Is not found free in nature. Is obtained from lactose, a disaccharide. Is important in cellular membranes.