1. Carbohydrates C483 Spring 2013

2. 1. Examine the Fischer projection below. How is this carbohydrate classified? A) L enantiomer; aldopentose. B) L enantiomer; ketopentose. C) D enantiomer; aldohexose. D) D enantiomer; ketopentose. 2. Which is the proper Haworth projection of β-D-galactopyranose?

3. 3.Which statement is not true about this structure? A.It is a ketose B.It is a beta anomer. C.It is a furanose. D.It is a pentose. 4. What is the name of the disaccharide shown below that is formed by joining two monomers of D-glucose? A) β-D-glucopyranosyl-(1→4)-β-D-glucopyranose. B) α-D-glucopyranosyl-(1→4)-α-D-glucopyranose. C) β-D-glucofuranosyl-(1→4)-β-D-glucofuranose. D) α-D-glucopyranosyl-(1→3)-β-D-glucopyranose.

4. Objectives Recognize particular carbohydrate structures Know general structural elements of cyclic monosaccharides and disaccharides, and their implications for structure/function Predict the products of condensation reactions and hydrolysis

5. Straight-chain Monosaccarides Aldose/ketose terminology Triose, tetrose, pentose, hexose Recognize isomerization (TPI—see page 173) – Should I know the mechanism?

6. Stereochemistry D/L designation Fisher Projections

7. Aldose Tree

8. Ketose Tree

9. Structures to Know D-glucose D-glyceraldehyde D-Ribose D-Galactose D-fructose dihydroxyacetone

10. Cyclic Monosaccharides Pyranose Haworth Projection Anomeric carbon Alpha and beta anomers

11. Cyclic Monosaccharides Furanose Just focus on what is commonly observed – Pyranoses: glucose, galactose – Furanoses: ribose, fructose X

12. Conformations Haworth and chair (no envelopes, etc)

13. Mutarotase Reaction of cyclic carbohydrates which equilibrates anomers

14. Section 8.4 Sugar Phosphates

15. Structure of Disaccharides Condensation of Monosacharides – Loss of anomeric hydroxyl group and proton of nucleophilic alcohol – Glycosidic Bond

16. Structure of Disaccharides Nomenclature of linkage – Find the acetal! Reducing sugar – Find the hemiacetal! “Lactose” – Reducing sugar – Nonreducing sugar – Linkage (number and stereochemistry)

17. Polysaccharides

18. Starch and Glycogen

19. Cellulose Watch structure carefully!

20. Answers 1.B 2.I 3.D 4.A