Cell Respiration The process by which cells turn food molecules into cell energy

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  • Cell RespirationThe process by which cells turn food molecules intocell energy

  • The Complete breakdown of foods occurs in aerobic respirationThe general reaction of aerobic respiration is: glucose + O2 CO2 + H2O + ATP + heat

    This reaction occurs in steps:GlycolysisTransition reactionKrebs CycleElectron Transport Chain

  • GlycolysisOccurs in the cytoplasmSplits a 6-carbon sugar into 2 x 3-C pyruvatesReaction sequence:Sugar (6C) 2 Pyruvates (3C)Produces:2 ATP molecules2 NADH2

  • Transition reactionProcesses pyruvate so that it can enter mitochondrionThe reaction sequence: 2 pyruvate (3C) 2 acetyl (2C)Produces:2 NADH22 acetyl groups easily enter the mitochondrion of the cell

  • Transition between cytoplasm and mitochondrion

  • Krebs CycleOccurs in the cytoplasm of the mitochondria (stroma)Cyclical series of reactions which breaks down acetyls releasing CO2Produces:2 ATPs6 NADH22 FADH2

  • Up to this point, the entire molecule of glucose has been broken down to form 6 CO2sYet, only 4 ATPs have been formed during:GlycolysisTransition &Krebs CyclePotential energy of NADH2 and FADH2 can be released in Electron Transport Chain

  • Electron Transport Chain harvests potential energy of NAD and FAD coenzymes

    Occurs along inner membrane (cristae) of mitochondrion

  • Overall Energy Harvest of Aerobic Cell RespirationMuch more ATP than the 4 molecules received through Gly, Trans, and Krebs!!

  • We metabolize more than sugars!!

  • Can cells produce ATP without oxygen being present?Oxygen removes e-s from the Electron Transport Chain to help make ATPIf oxygen is not present, NADH2 must be oxidized to NAD+ to allow cells to make ATP

  • Animal cells engage in fermentationFermentation allows NAD+ to be recycled

    Fermentation produces 2 ATPs per molecule of glucose broken down

    Glucose is not completely broken down

  • Plant and fungal cellsengage in fermentationThis process also allows NAD+ to be recycledProduces 2 ATPs per molecule of glucose broken downGlucose is not completely broken down

  • Fermentations producemany foods and drinks!Dairy fermentationsCheesesYogurtsSour creamFermented foodsBreads Tofu and tempehPickles, sauerkrautFermented beveragesWines, beers, ales


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