CH 460 Dr. Muccio Worksheet 4

1. What is the difference between an aldose and a ketose?

2. What is the oxidation number of the carbon on the following 3 groups?

3. Circle the carbons in the figure below that are chiral. How many isomers does this molecule have?

4. What is the difference between an epimer and an enantiomer?

5. How is the Fisher projection of D-glucose converted to L-glucose?

6. The chemical formula of a tetrose monosaccharide is _____. a. C6H12O6 b.C4H10O4 c.C6H10O4 d.C4H8O4 e.None

7. Match the carbohydrates to their descriptions on the left.

i. D-Glyceraldehyde _____ A. C-2 Epimer of Glucose ii. D-Threose _____ B. C-2 Epimer of Threose iii. D-Ribose _____ C. Pentose with D,D,D stereochem iv. D-Mannose _____ D. Triose v. D-Galactose _____ E. Hexose with DLDD stereochem vi. D-Erythrose _____ F. C-3 Epimer of Ribose vii. D-Xylose _____ G. C-4 Epimer of Glucose viii. D-Glucose _____ H. C-2 Epimer of Erythrose ix. D-Arabinose _____ I. C-2 Epimer of Ribose x. D-Fructose _____ J. Ketose of Letter D xi. D-Xylulose _____ K. Ketose of Letter F xii. D-Erythrulose _____ L. Enantiomer of Letter A xiii. Dihydroxyacetone ____ M. Ketose of Letter B xiv. D-Ribulose _____ N. Ketose of Letter E xv. L-Mannose _____ O. Ketose of Letter C

CH 460 Dr. Muccio Worksheet 4 8. In the conversion of aldoses to their ketoses, the _____ carbon loses its stererochemistry. a. C-3 b.C-2 c.C-4 d.C-5 e.C-1

9. The generic form of a hemiacetal is ______? a. R-O-C-H b. R-C-O-H c. R-OR-CH-OH d. R-C-C-OH e. none

10. In Haworth projection of carbohydrates, the D and L prefix denotes the position of the ______group on carbon ______. a. Carbonyl; 6 b. OH; 5 c. O-; 6 d. OH; 6 e. Carbonyl; 5

11. Below is the Haworth Projection of ______.

a. α-L-Glucopyranose b. α-D-Glucopyranose c. β-D- Glucopyranose d. β-L-Glucopyranose e. D-Glucose

12. Galactose forms a (furanose/pyranose) ring structure whereas fructose forms a (furanose/pyranose).

13. ______inverts the position of the anomeric carbon. The ring structure of carbohydrates is ______stable than the open chain form. a. a. Epimerization; more c. Mutarotation; more b. c. Epimerization; less d. Mutarotation; less

14. The ______position on the anomeric carbon is the more stable. a. L b. D c. β d. α

15. The ______anomer of the ______form of ribose is the more stable. It occurs in a ______:1 ratio. a. β; pyranose; 3 b. β; furanose; 4 c. α; pyranose; 3 d. α; furanose; 4

16. Can you identify the reducing and non-reducing end of the disaccharide below? Put a star on the acetal carbon and a triangle around the hemiacetal carbon. Name the sugar below.

CH 460 Dr. Muccio Worksheet 4

17. Which of the following disaccharides does not have a reducing end? a. Lactose b. Glucose c. Cellobiose d. Sucrose e. Amylopectin

18. Match the di/polysaccharides to their descriptions on the left. Some will have multiple matches. i) β-Glc (14)Glc ______A. Cellobiose ii) α-Glc (12)-β-Fru ______B. Sucrose iii) α-Glc (14)Glc ______C. Branched homoglycan of Glc iv) β-Fru (21)-α-Glc ______D. Maltose v) β-Gal (14)Glc ______E. Linear homoglycan of Glc vi) Amylopectin ______F. Has no reducing ends vii) Cellulose______G. Has α(1,6) branches viii)Amylose ______H. Lactose I. Linear polymer of Glc with β(1,4) glycosidic bonds J. 100% sweet K. Humans cannot digest – not nutritional L. hydrolyzed by Cellulases that break β(1,4) bonds M. Makes up a minority of plant starch N. Makes up a majority of plant starch