1. 1 Announcements & Agenda (04/11/07) New Extra Credit Assignment Due Monday Pick Up Old Graded Stuff Pick Up Flowchart if you were absent Monday Quiz Friday (13.4, 13.5, & Ch 14) Exam Fri 04/20 (Ch 13,14,15) Will Post Practice Exam Soon! Will Post Practice Exam Soon!Today Finish Cyclic Monosaccharides Finish Cyclic Monosaccharides Reactions of carbohydrates Reactions of carbohydrates Disaccharides Disaccharides Polysaccaharides Polysaccaharides

2. 2 What sugar is this? 1.Mannose 2.Glucose 3.Fructose 4.Galactose 12345

3. 3 Is this the L- form or the D-form? 1.L 2.D 3.B 12345

4. 4 Which Structure is Correct? 1.A 2.B 3.C 4.D 12345

5. 5 Last Time: Formation of Cyclic Glucose Two “anomers” possible:  and  ; this one is alpha b/c the –OH is opposite the -CH 2 OH group!

6. 6 Mutarotation: Interconversion of Anomers cyclic structures open and close.cyclic structures open and close.  -D-glucose converts to β-D-glucose & vice versa.  -D-glucose converts to β-D-glucose & vice versa. at any time, only a small amount of open chain forms.at any time, only a small amount of open chain forms.  -D-glucose D-glucose (open) β-D-glucose  -D-glucose D-glucose (open) β-D-glucose (36%) (trace) (64%) (36%) (trace) (64%) O H CH 2 OH OH O C H OH OH OH OH OH OH CH 2 OH O OH OH OH OH CH 2 OH O

7. 7 D-fructose  -D-fructose α-D-fructose Cyclic Structure of Fructose is a ketohexose.is a ketohexose. reacts the -OH on C-5 with the C=O on C-2reacts the -OH on C-5 with the C=O on C-2 -OH from C5 attaches to C from C=O!

8. 8 Chemical Properties of Monosaccharides (14.4)

9. 9 Reducing Sugars Reducing Sugars are monosaccharides that oxidize to give a carboxylic acid.are monosaccharides that oxidize to give a carboxylic acid. undergo reaction in the Benedict’s test.undergo reaction in the Benedict’s test. include the monosaccharides glucose, galactose, and fructose.include the monosaccharides glucose, galactose, and fructose. many disaccharides can also oxidizemany disaccharides can also oxidize but only if one monosaccharide can ring open! (see later slides) but only if one monosaccharide can ring open! (see later slides)

10. 10 Oxidation of D-Glucose Oxidation of D-Glucose [O] QUESTION: WHY CAN FRUCTOSE (A KETONE) BE OXIDIZED??? ANSWER: ISOMERIZATION TO AN ALDEHYDE…

11. 11 One Test for Glucose in Urine: Benedict’s Test

12. 12 Reduction of Monosaccharides Reduction of Monosaccharides involves the carbonyl group.involves the carbonyl group. produces sugar alcohols, or alditols.produces sugar alcohols, or alditols. such as D- glucose gives D-glucitol also called sorbitol.such as D- glucose gives D-glucitol also called sorbitol. D-Glucitol

13. 13 Learning Check Write the products of the oxidation and reduction of D-mannose. D-mannose

14. 14 Solution D-mannitol D-mannose D-mannonic acid

15. 15 Disaccharides (14.5)

16. 16 Important Disaccharides: Know These 3 A disaccharide consists of two monosaccharides. Monosaccharides Disaccharide glucose + glucose maltose + H 2 O glucose + glucose maltose + H 2 O glucose + galactoselactose + H 2 O glucose + fructosesucrose + H 2 O

17. 17 Maltose Free α-OH A.K.A. “malt sugar” obtained from starch hydrolysis used in cereals, candies, and brewing linked by an  -1,4- glycosidic bond formed from the  −OH on C1 of the 1st glucose and −OH on C4 of the 2nd glucose found in both the  - and β - forms

18. 18 Lactose a disaccharide of β-D-galactose and α- or β-D- glucose.a disaccharide of β-D-galactose and α- or β-D- glucose. contains a β -1,4- glycosidic bond.contains a β -1,4- glycosidic bond. is found in milk and milk products.is found in milk and milk products. α-form

19. 19 Sucrose Sucrose or table sugar is obtained from sugar cane and sugar beets.is obtained from sugar cane and sugar beets. consists of α-D-glucose and β-D-fructose.consists of α-D-glucose and β-D-fructose. has an α,β-1,2-glycosidic bond.has an α,β-1,2-glycosidic bond. α-D-glucose β -D-fructose Is a non-reducing sugar. Why?

20. 20 Learning Check Write the structures of the two monosaccharides that form when sucrose is hydrolyzed.

21. 21 Solution

22. 22 Polysaccharides often polymers of D-glucose.often polymers of D-glucose. include amylose & amylopectin, starches made of α-D-glucose.include amylose & amylopectin, starches made of α-D-glucose. include glycogen (animal starch in muscle), which is made of α- D-glucose.include glycogen (animal starch in muscle), which is made of α- D-glucose. include cellulose (plants and wood), which is made of β-D- glucose.include cellulose (plants and wood), which is made of β-D- glucose. α-D-Glucose

23. 23 Starch: Structures of Amylose & Amylopectin

24. 24 Amylose a polymer of α-D- glucose molecules.a polymer of α-D- glucose molecules. linked by  -1,4 glycosidic bonds.linked by  -1,4 glycosidic bonds. a continuous (unbranched) chain.a continuous (unbranched) chain.

25. 25 Amylopectin also a polymer of α-D-glucose molecules.also a polymer of α-D-glucose molecules. is a branched-chain polysaccharide.is a branched-chain polysaccharide. has α-1,4- glycosidic bonds between the glucose units.has α-1,4- glycosidic bonds between the glucose units. has α-1,6 bonds to branches.has α-1,6 bonds to branches.

26. 26 Glycogen is the polysaccharide that stores α-D- glucose in muscle.is the polysaccharide that stores α-D- glucose in muscle. is similar to amylopectin, but is more highly branched.is similar to amylopectin, but is more highly branched.

27. 27 Cellulose a polysaccharide of glucose units in unbranched chains.a polysaccharide of glucose units in unbranched chains. has β-1,4-glycosidic bonds.has β-1,4-glycosidic bonds. cannot be digested by humans because humans cannot break down β-1,4- glycosidic bonds.cannot be digested by humans because humans cannot break down β-1,4- glycosidic bonds.

28. 28 Learning Check Identify the polysaccharides and types of glycosidic bonds in each of the following. A.B.C.

29. 29 Solution A. Cellulose  -1,4-glycosidic bonds B. Amylose  -1,4-glycosidic bonds Amylopectin  -1,4-and  -1,6-glycosidic bonds Amylopectin  -1,4-and  -1,6-glycosidic bonds C. Glycogen  -1,4-and  -1,6-glycosidic bonds (more branched than amylopectin) (more branched than amylopectin)

30. 30 Other cool sugars… Chitin (glucose w/ amide) = insect exoskeleton. Similar to that in bacterial cell wall; makes bacterial cells hard to break open. Lysozyme – defense protein to break down cell walls Cell surface, including ABO blood groups.

31. 31 You are responsible for the Health Note on Page 485!

32. 32 More Interesting Info: Sweetness of Sweeteners Sugars differ in sweetness.Sugars differ in sweetness. are compared to sucrose (table sugar), which is assigned a value of 100.are compared to sucrose (table sugar), which is assigned a value of 100. 60 000

33. 33 History of Artificial Sweeteners Saccharin: http://en.wikipedia.org/wiki/Saccharin http://en.wikipedia.org/wiki/Saccharin 1879 Ira Remsen and Constantin Fahlberg at JHU Monsanto Chemical Company in Saint Louis became profitable in manufacturing and selling saccharin. Aspartame (Nutrasweet) was originally patented by GD Searle in Chicago. 1985 Monsanto bought GD Searle and created the NutraSweet Company. Neotame (an analog of Aspartame) is 5 times sweeter than Aspartame. See http://www.neotame.com/

34. 34 Chapter 15: Lipids… mmm…Fat… 15.1 Lipids 15.2 Fatty Acids