1.Metabolism: The sum of the chemical reactionsin an organismA metabolic pathway is a sequence of enzymaticallycatalyzed chemical reactions in a cellMetabolic pathways are determined by enzymes

2. Catabolic and Anabolic Reactions Catabolism: Provides energy and building blocks foranabolism. (Break down) Anabolism: Uses energy and building blocks to buildlarge molecules. (Synthesis) 3. Metabolism: the sum of Catabolism andAnabolism Oxidation: the loss or removal of electrons Reduction: the gain of electrons 4. Role of ATP in Coupling Reactions Figure 5.1 5. Oxidation-Reduction Reactions Oxidation: Removal of electrons Reduction: Gain of electrons Redox reaction: An oxidation reaction paired with a reduction reaction 6. Oxidation-Reduction Reactions In biological systems, the electrons are often associatedwith hydrogen atoms. Biological oxidations are oftendehydrogenations 7. The Generation of ATP ATP is generated by the phosphorylation of ADP 8. Substrate-Level Phosphorylation Energy from the transfer of a high-energy PO4 to ADP generates ATP 9. Oxidative Phosphorylation Energy released from transfer of electrons (oxidation) of one compound to another (reduction) is used to generate ATP in the electron transport chain 10. Carbohydrate Catabolism The breakdown of carbohydrates to release energy Glycolysis Krebs cycle Electron transport chain 11. Glycolysis The oxidation of glucose to pyruvic acid produces ATP and NADHFigure 5.11 12. Preparatory Stage of Glycolysis 2 ATP are used Glucose is split to form 2 glyceraldehyde-3-phosphateFigure 5.12, steps 15 13. Energy-Conserving Stage ofGlycolysis 2 glucose-3-phosphateoxidized to 2 pyruvic acid 4 ATP produced 2 NADH produced Figure 5.12, steps 610 14. The Reactions of Glycolysis 15. The Krebs Cycle Oxidation of acetyl CoA produces NADH and FADH2 16. The Krebs CycleFigure 5.13 17. The Reactions of the Krebs Cycle 18. The Electron Transport Chain A series of carrier molecules that are, in turn, oxidizedand reduced as electrons are passed down the chain Energy released can be used to produce ATP bychemiosmosis 19. Overview of Respiration andFermentationFigure 5.11 20. Chemiosmotic Generation of ATPFigure 5.16 21. An Overview of Chemiosmosis Figure 5.15 22. A Summary of Respiration Aerobic respiration: The final electron acceptor inthe electron transport chain is molecular oxygen (O2). Anaerobic respiration: The final electron acceptor inthe electron transport chain is not O2. Yields lessenergy than aerobic respiration because only part ofthe Krebs cycles operates under anaerobic conditions. 23. RespirationFigure 5.16 24. Carbohydrate Catabolism Energy produced from complete oxidation of oneglucose using aerobic respiration PathwayATP ProducedNADHFADH2Produced ProducedGlycolysis 22 0Intermediate step02 0Krebs cycle26 2Total4102 25. Carbohydrate Catabolism ATP produced from complete oxidation of one glucose using aerobic respiration By Oxidative PhosphorylationPathway By Substrate-Level Phosphorylation From NADHFrom FADHGlycolysis2 6 0Intermediate step 0 6 0Krebs cycle 218 4Total 430 4 26. Carbohydrate Catabolism 36 ATPs are produced in eukaryotes By Oxidative PhosphorylationPathway By Substrate-Level Phosphorylation From NADHFrom FADHGlycolysis2 6 0Intermediate step 0 6Krebs cycle 218 4Total 430 4 27. Fermentation One process by which pyruvate is subsequently metabolized in the absence of oxygen The result of the need to recycle the limited amount of NAD by passing the electrons of reduced NAD to other molecules Homolactic acid fermentation: pyruvate is converted directly to lactic acid, using electrons from reduced NAD Alcoholic fermentation: carbon dioxide is released from pyruvate to form acetaldehyde, which is reduced to ethanol 28. Fermentation Any spoilage of food by microorganisms (general use) Any process that produces alcoholic beverages oracidic dairy products (general use) Any large-scale microbial process occurring with orwithout air (common definition used in industry) 29. Fermentation Scientific definition: Releases energy from oxidation of organic molecules Does not require oxygen Does not use the Krebs cycle or ETC Uses an organic molecule as the final electron acceptor 30. An Overview of Fermentation Figure 5.18a 31. Types of FermentationFigure 5.19 32. Requirements of ATP ProductionFigure 5.27 33. A Nutritional Classification ofOrganismsFigure 5.28 34. A Nutritional Classification ofOrganismsFigure 5.28 35. A Nutritional Classification ofOrganismsFigure 5.28 36. Metabolic Diversity amongOrganisms Nutritional Type Energy SourceCarbon Source ExamplePhotoautotrophLight CO2Oxygenic: Cyanobacteria plants Anoxygenic: Green, purple bacteriaPhotoheterotrophLight OrganicGreen, purple nonsulfurcompoundsbacteriaChemoautotrophChemicalCO2Iron-oxidizing bacteriaChemoheterotrophChemicalOrganicFermentative bacteriacompoundsAnimals, protozoa, fungi, bacteria.