Lecture Biology - Chapter 7: Pathways that harvest chemical energy. The topics discussed in this chapter are: How does glucose oxidation release chemical energy? What are the aerobic pathways of glucose metabolism? How is energy harvested from glucose in the absence of oxygen? How does the oxidation of glucose form ATP? Why does cellular respiration yield so much more energy than fermentation? How are metabolic pathways interrelated and controlled? | Pathways That Harvest Chemical Energy 7 Pathways That Harvest Chemical Energy How Does Glucose Oxidation Release Chemical Energy? What Are the Aerobic Pathways of Glucose Metabolism? How Is Energy Harvested from Glucose in the Absence of Oxygen? How Does the Oxidation of Glucose Form ATP? Why Does Cellular Respiration Yield So Much More Energy Than Fermentation? How Are Metabolic Pathways Interrelated and Controlled? How Does Glucose Oxidation Release Chemical Energy? Fuels: molecules whose stored energy can be released for use. The most common fuel in organisms is glucose. Other molecules are first converted into glucose or other intermediate compounds. How Does Glucose Oxidation Release Chemical Energy? Principles governing metabolic pathways: Complex chemical transformations occur in a series of reactions. Each reaction is catalyzed by a specific enzyme. Metabolic pathways are similar in all organisms. In eukaryotes, metabolic pathways are compartmentalized in organelles. Each pathway is regulated by key enzymes. How Does Glucose Oxidation Release Chemical Energy? Burning or metabolism of glucose: Glucose metabolism pathway traps the free energy in ATP: How Does Glucose Oxidation Release Chemical Energy? ΔG from complete combustion of glucose = –686 kcal/mole Highly exergonic; drives endergonic formation of many ATP Figure Energy for Life Three metabolic pathways involved in harvesting the energy of glucose How Does Glucose Oxidation Release Chemical Energy? If O2 is present, four pathways operate: Glycolysis, pyruvate oxidation, citric acid cycle, and electron transport chain. If O2 is not present, pyruvate is metabolized in fermentation. Figure Energy-Producing Metabolic Pathways How Does Glucose Oxidation Release Chemical Energy? Redox reactions: one substance transfers electrons to another substance Reduction: gain of one or more electrons by an atom, ion, or molecule Oxidation: loss of one or more . | Pathways That Harvest Chemical Energy 7 Pathways That Harvest Chemical Energy How Does Glucose Oxidation Release Chemical Energy? What Are the Aerobic Pathways of Glucose Metabolism? How Is Energy Harvested from Glucose in the Absence of Oxygen? How Does the Oxidation of Glucose Form ATP? Why Does Cellular Respiration Yield So Much More Energy Than Fermentation? How Are Metabolic Pathways Interrelated and Controlled? How Does Glucose Oxidation Release Chemical Energy? Fuels: molecules whose stored energy can be released for use. The most common fuel in organisms is glucose. Other molecules are first converted into glucose or other intermediate compounds. How Does Glucose Oxidation Release Chemical Energy? Principles governing metabolic pathways: Complex chemical transformations occur in a series of reactions. Each reaction is catalyzed by a specific enzyme. Metabolic pathways are similar in all organisms. In eukaryotes, metabolic pathways are .
