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Cellular Respiration! What do living things do with food? • Produce materials that bodies need to grow • Materials can be converted to energy C6H12O6 + 6O2 Enzymes 6CO2 + 6H2O + energy things release energy from Cellular respiration! • Begins with glycolysis food?? • break down glucose pyruvic acid • small amount energy released (ATP) Overview No oxygen Fermentation Lactic Acid Alcoholic Glycolysis (in cytoplasm) • Glucose (6C) split into: – 2 pyruvic acid (3C) – Result: 2 ATP & 2 NADH • **4ATP formed, 2 used → net gain = 2ATP Who uses glycolysis? • ALL organisms!!! • Glycolysis does NOT require oxygen → small amts of energy formed without O2 • As form ATP, available NAD+ decreases decreases ATP synthesis of glycolysis Fermentation! • NADH converted to NAD+ • Anaerobic respiration - does not require O2 Two Types 1. Lactic Acid 2. Alcoholic What do these items have to do with fermentation? 1. Lactic acid fermentation • Pyruvic acid converted to lactic acid • Lactic acid forming microorganisms used in making foods (Ex: yogurt, cheese, sour cream) • Lactic acid build up in muscles causes cramps 1. Alcoholic fermentation • Pyruvic acid converted to CO2 and ethyl alcohol • Basis for wine and beer industry; bread Efficiency of anaerobic respiration • Glycolysis produces how many ATP molecules? TWO • This is ~2% energy in glucose Can any organisms Aerobic Respiration No oxygen Fermentation Lactic Acid Alcoholic Aerobic respiration • Energy in pyruvic acid released using oxygen • Produces 20x more ATP than glycolysis! 2 major stages 1. Krebs cycle 2. Electron transport chain Where does respiration occur? Prokaryotes • Respiration occurs in cytosol Anaerobic or aerobic? Eukaryotes • Kreb cycle and ETC occur in mitochondria A little about the mitochondria… 1. Pyruvic acid diffuses across membrane, enters matrix • Matrix – contains enzymes used in Krebs cycle 2. Pyruvic acid reacts with Coenzyme A to form acetyl CoA (produces 2 NADH) Pyruvic Acid (C-C-C) Coenzyme A Acetyl CoA (C-C) Part I. The Krebs Cycle Overview: energy molecules & waste products formed as Acetyl CoA broken down • Acetyl CoA forms citric acid • CO2 molecules are released • **NADH, FADH2, ATP formed Energy Tally • Glycolysis – 2 ATP 2 NADH • Conversion to – 2 NADH Acetyl CoA • Krebs cycle – 2 ATP 6 NADH 2 FADH2 12 energy molecules to next stage Part II. Electron Transport Chain • Embedded in inner membrane of mitochondria • Water released as waste byproduct • High energy electrons converted to ATP • Each NADH forms 3 ATP FADH2 forms 2 ATP Energy Conversion **The Rules: NADH = 3 ATP FADH2 = 2 ATP Glycolysis – 2 NADH _____ ATP Conversion to – 2 NADH _____ ATP Acetyl CoA Krebs ETC cycle - 6 NADH 2 FADH2 ____ ATP? ____ ATP ____ ATP