Organic Chemistry,7th Edition L.G.Wade,Jr. Chapter 23 Carbohydrates and Nucleic Acids Copyright 2010 Pearson Education,Inc
Chapter 23 Copyright © 2010 Pearson Education, Inc. Organic Chemistry, 7th Edition L. G. Wade, Jr. Carbohydrates and Nucleic Acids
Carbohydrates Synthesized by plants using sunlight to convert CO2 and H2O to glucose and O2. Polymers include starch and cellulose. -Starch is a storage unit for solar energy. Most sugars have formula C(H2O)n, “hydrate of carbon." Chapter 23 2
Chapter 23 2 Carbohydrates ▪ Synthesized by plants using sunlight to convert CO2 and H2O to glucose and O2 . ▪ Polymers include starch and cellulose. ▪ Starch is a storage unit for solar energy. ▪ Most sugars have formula Cn (H2O)n , “hydrate of carbon
Classification of Carbohydrates Monosaccharides or simple sugars: polyhydroxyaldehydes or aldoses polyhydroxyketones or ketoses Disaccharides can be hydrolyzed to two monosaccharides. Polysaccharides hydrolyze to many monosaccharide units.For example, starch and cellulose have 1000 glucose units. Chapter 23 3
Chapter 23 3 Classification of Carbohydrates ▪ Monosaccharides or simple sugars: ▪ polyhydroxyaldehydes or aldoses ▪ polyhydroxyketones or ketoses ▪ Disaccharides can be hydrolyzed to two monosaccharides. ▪ Polysaccharides hydrolyze to many monosaccharide units. For example, starch and cellulose have > 1000 glucose units
Monosaccharides CHO CH,OH CHOH 2C=0 CHOH CHOH CHO CH,OH CHOH CHOH CHOH 2C=0 SCHOH SCHOH CHOH CHOH CH,OH CH,OH CH,OH CH,OH an aldohexose a ketohexose an aldotetrose a ketotetrose Copyright 2010 Pearson Prentice Hall,Inc. Classified using three criteria: If it contains a ketone or an aldehyde group. Number of carbons in the chain. Configuration of the asymmetric carbon farthest from the carbonyl group. Chapter 23 4
Chapter 23 4 Monosaccharides ▪ Classified using three criteria: ▪ If it contains a ketone or an aldehyde group. ▪ Number of carbons in the chain. ▪ Configuration of the asymmetric carbon farthest from the carbonyl group
(+)and (-)-Glyceraldehydes CHO CHO H-C✉OH HO-CH CH,OH CH,OH (+)-glyceraldehyde (-)-glyceraldehyde D series of sugars L series of sugars Copyright 2010 Pearson Prentice Hall,Inc The (+)enantiomer of glyceraldehyde has its OH group on the right of the Fischer projection. The (-)enantiomer of glyceraldehyde has its OH group on the left of the Fischer projection. Chapter 23 5
Chapter 23 5 (+) and (-)-Glyceraldehydes ▪ The (+) enantiomer of glyceraldehyde has its OH group on the right of the Fischer projection. ▪ The (-) enantiomer of glyceraldehyde has its OH group on the left of the Fischer projection