Cell respiration Definition: The series of chemical reactions in cells which oxidize food energy (Carbohydrates, proteins, lipids) into cell energy (ATP)

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    14-Dec-2015

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Cell respiration Definition: The series of chemical reactions in cells which oxidize food energy (Carbohydrates, proteins, lipids) into cell energy (ATP) and heat; may occur with or without O2 being used as the terminal electron acceptor (aerobically or anaerobically) General equation: Glucose + O2 CO2 + H2O + ATP + Heat Slide 2 The bottom line of cell respiration is the production of ATP (cell energy) ATP can be produced in 1 of 3 ways: 1)Substrate-level phosphorylation: Essentially, Food-P + ADP food + ATP 2) Oxidative phosphorylation: Occurs as NADH2 and FADH2 relay e-s to an ETC, setting up an electrochemical gradient of H+s which is relieved by ATPase which uses kinetic energy of proton flow to form ATP from ADP + Pi 3) Photophosphorylation: during photosynthesis Slide 3 Substrate-level phosphorylation -occurs during the rxns of Glycolysis and the Krebs Cycle Slide 4 Oxidative Phosphorylation: occurs during the rxns of the Electron Transport Chain along inner membrane (cristae) of the mitochondrion Slide 5 The complete oxidation of food Aerobic respiration Glucose + O2 CO2 + H2O + energy Equation: Glucose + O2 CO2 + H2O + energy The above set of reactions occur in 4 distinct steps: 1)Glycolysis splits 6-C glucose into 2 X 3-C pyruvic acids (pyruvates) 2)Pyruvate oxidation removes 1 C from each pyruvate to form 2 X 2-C acetyl groups which may enter the rxns of the Krebs Cycle 3)Krebs Cycle cyclical series of rxns which break down each of the 2-C acetyl groups into 2 CO2 4)Electron Transport Chain electron carrying coenzymes relay their e-s to a series of electron carrying proteins to O2 setting up an electrochemical gradient which is relieved through ATPase which transforms the kinetic energy of proton flow into ATP formation Slide 6 During each step of the process, energy is released!! In Glycolysis: 4 total ATPs are formed (yet, there is only a net gain of 2 ATPs) and 2 NAD coenzymes are reduced to NADH2 In Pyruvate oxidation: 2 NADH2s are produced In the Krebs Cycle: 2 ATPs are formed, 6 NADH2s are produced, and 2 FADH2s In Electron Transport: 32 ATPs are formed as 10 NADH2s and 2 FADH2s are oxidized back to NAD+ and FAD+ and recycled back to the system and re-used Slide 7 1 2 3 4 ETC Slide 8 The reactions of cell respiration: Glycolysis Slide 9 The reactions of cell respiration: Pyruvate oxidation Slide 10 The reactions of cell respiration: the Krebs Cycle Slide 11 the Electron Transport Chain Slide 12 Overview of aerobic respiration General equation: glucose + O2 CO2 + H2O + energy Glucose is oxidized (broken down) to form 6 CO2 E-s stripped away from glucose are relayed to ETC by NAD+ and FAD+ coenzymes and accepted by O2 O2 is the terminal electron acceptor ETC relays e-s and pumps H+s (protons) [H+] outside of ETC membrane is relieved by ATPase H+s flow through ATPase ATPase transforms kinetic flow of H+s into bond between ADP and P

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