Chapter 9 – Cellular Respiration & FermentationIntroducing ATPThe Nature of Chemical Energy and Redox ReactionsStructure and Function of ATPSlide 5ATP Hydrolysis and Protein PhosphorylationSlide 7How Does ATP Drive Endergonic Reactions?Slide 9What Is a Redox Reaction?The Gain or Loss of an Electron Can Be RelativeSlide 12Electrons Are Usually Accompanied by ProtonsSlide 14What Happens When Glucose Is Oxidized?An Overview of Cellular RespirationSlide 17The Steps of Cellular RespirationSlide 19Glycolysis: Processing Glucose to PyruvateThe Glycolysis ReactionsSlide 22Slide 23Methods of Producing ATPSlide 25Feedback InhibitionSlide 27Feedback Inhibition Regulates GlycolysisSlide 29The Remaining Reactions Occur in the MitochondriaSlide 31Pyruvate ProcessingSlide 33Pyruvate Processing RegulationThe Citric Acid CycleThe Substrates of the Citric Acid CycleSlide 37The Citric Acid Cycle Regulation and SummarySlide 39Glucose Oxidation SummarySlide 41Free Energy Changes, NADH, and FADH2Slide 43The Electron Transport ChainOxidative PhosphorylationElectron Transport and ChemiosmosisSlide 47The Chemiosmotic HypothesisHow Is the Electron Transport Chain Organized?Slide 50ATP Synthase StructureSlide 52ATP Yield from Cellular RespirationSlide 54Aerobic and Anaerobic RespirationOxygen as a Final Electron AcceptorFermentationSlide 58Different Fermentation PathwaysSlide 60Fermentation and Cellular Respiration EfficiencyCellular Respiration Interacts with Metabolic PathwaysSlide 63Processing Proteins and Fats as FuelSlide 65Anabolic Pathways Synthesize Key MoleculesSlide 67Key ConceptsSlide 69© 2011 Pearson Education, Inc.Chapter 9 – Cellular Respiration & Fermentation© 2011 Pearson Education, Inc.Introducing ATP•ATP (adenosine triphosphate) is the cellular currency for energy – it provides the fuel for most cellular activities.•ATP has high potential energy and allows cells to do work.•ATP works by phosphorylating (transferring a phosphate group) target molecules.© 2011 Pearson Education, Inc.The Nature of Chemical Energy and Redox Reactions•In cells, electrons are the most important source of chemical potential energy.•The amount of potential energy in an electron is based on its position relative to positive and negative charges. –Electrons closer to negative charges (from other electrons) and farther from positive charges (in nuclei of nearby atoms), have higher potential energy. •In general, a molecule’s potential energy is a function of its electrons’ configuration and position.© 2011 Pearson Education, Inc.Structure and Function of ATP•The electrons in ATP have high potential energy because the four negative charges in its three phosphate groups repel each other.•Hydrolysis of the bond between the two outermost phosphate groups results in formation of ADP and Pi (inorganic phosphate, H2PO4−) in a highly exergonic reaction.–The released phosphate group is transferred to a protein.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.ATP Hydrolysis and Protein Phosphorylation •Hydrolysis of ATP is exergonic because the entropy of the product molecules is much higher than that of the reactants.•Energy released during ATP hydrolysis is transferred to a protein during phosphorylation.–This phosphorylation usually causes a change in the protein’s shape.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.How Does ATP Drive Endergonic Reactions? When a protein is phosphorylated, the exergonic phosphorylation reaction is paired with an endergonic reaction in a process called energetic coupling. •In cells, endergonic reactions become exergonic when the substrates or enzymes involved are phosphorylated.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.What Is a Redox Reaction? •Reduction–oxidation reactions (redox reactions) are chemical reactions that involve electron transfer. –Redox reactions drive ATP formation.•When an atom or molecule gains an electron, it is reduced.•When an atom or molecule loses an electron, it is oxidized.•Oxidation and reduction events are always coupled—if one atom loses an electron, another has to gain it.–Electron donors are always paired with electron acceptors.file:///Users/ericarowe/Documents/UTK%20Biology/UTK%20Bio140%20Fall%202011/Chapter_09/A_PowerPoint_Lecture_Tools/09_Lecture_Outline/RedoxReactions.html© 2011 Pearson Education, Inc.The Gain or Loss of an Electron Can Be Relative•During a redox reaction, electrons can be transferred completely from one atom to another, or they can simply shift their position in covalent bonds.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.Electrons Are Usually Accompanied by Protons•Each electron transferred from one molecule to another during a redox reaction is usually accompanied by a proton (H+). –The reduced molecule gains a proton and has higher potential energy. –The oxidized molecule loses a proton and has lower potential energy.•Nicotinamide adenine dinucleotide (NAD) is reduced to form NADH.–NADH readily donates electrons to other molecules and is thus called an electron carrier and has “reducing power.”© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.What Happens When Glucose Is Oxidized? •The carbon atoms of glucose are oxidized to form carbon dioxide, and the oxygen atoms in oxygen are reduced to form water: C6H12O6 + 6 O2  6 CO2 + 6 H2O + energy glucose oxygen carbon water dioxide•In cells, glucose is oxidized through a long series of carefully controlled redox reactions. The resulting change in free energy is used to synthesize ATP from ADP and Pi. Together, these reactions comprise cellular respiration.© 2011 Pearson Education, Inc.An Overview of Cellular Respiration•All organisms use glucose to build fats, carbohydrates, and other compounds; cells recover glucose by breaking down these molecules.–Glucose is used to make ATP through either cellular respiration or fermentation.Cellular respiration produces ATP from a molecule with high potential energy – usually glucose. Each of the four steps of cellular respiration consists of a series of chemical reactions, and a distinctive starting molecule and characteristic set of products.© 2011 Pearson Education, Inc.© 2011 Pearson Education, Inc.The Steps of Cellular Respiration•Cellular respiration is any suite of reactions that produces ATP in an electron transport chain.•Cellular respiration has