13 1 Chemistry of Digestion Carbohydrates Digestion is

13. 1 Chemistry of Digestion: Carbohydrates Digestion is the hydrolysis of food molecules to small molecules for absorption and utilization by cells for energy and other metabolic needs. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 21 -6: Carbohydrate digestion

Chemistry of Digestion: Carbohydrates • Polysaccharides Starts in mouth • Disaccharides • Monosaccharide • (Absorption) animation Nothing happens in the stomach because it is too acidic. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Completed in small intestine

Chemistry of Digestion: Carbohydrates Mouth Small intestine Blood Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings Figure 21 -6: Carbohydrate digestion

Fig. 13. 2 Summary of carbohydrate digestion in the human body. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

13. 2 Glycolysis Fig. 13. 3 An overview of glycolysis. see handout KNOW for all 10 reactions: 1. Structures and names of carbohydrates and metabolites 2. Symbols of all cofactors 3. Reaction types 4. Enzyme names Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Summary of ATP production from glucose in glycolysis Table 24. 1 6 2(glyceraldehyde-3 -phosphate 1, 3 -bisphoglycerate 2 NADH 3 ATP total ATP from glycolysis 5 ATP Each NADH in cytosol eventually yields 1. 5 ATP (see the next slide) Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Fig. 13. 8 The dihyroxyacetone phosphate-glycerol 3 phosphate shuttle to. Each FADH 2 yields 1. 5 ATP in the ETC Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings ETC

13. 2 Glycolysis (cont. ) Regulation of glycolysis Rxn 1. Glucose-6 -phosphate inhibits this step Rxn 3. ATP inhibits this step Rxn 10. ATP inhibits this step Note: 1. A ll enzymes that are regulated are “kinase” enzymes. 2. High levels of ATP (low bodily energy use) inhibits glycolysis. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

13. 3 Fates of pyruvate Fig. 13. 6 The three common fates of pyruvate generated by glycolysis. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

← Fig. 13. 7 All three of the common fates of pyruvate from glycolysis provide for the regeneration of NAD+ from NADH. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Fig. 13. 10 Pyruvate also makes oxaloacetate Oxaloacetate is involved in both gluconeogenesis and the Krebs cycle. Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

• NADH from pyruvate acetyl-Co. A yields • 5 ATP in the mitochondrial matrix Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Page 470. Summary of glucose metabolism Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

• Total ATP from metabolism of glucose C 6 H 12 O 6 + O 2 6 CO 2 + 6 H 2 O • Glycolysis 5 ATP • Pyruvate 5 ATP • Krebs cycle 20 ATP 30 ATP Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Fig. 13 The relationships among four common metabolic pathways that involve glucose. oxaloacetate Krebs cycle Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings

Page 470. Summary of glucose metabolism Copyright © 2004 Pearson Education, Inc. , publishing as Benjamin Cummings