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    So I've been trying to teach myself respiration (not been taught in class yet) and the ocr textbook is very unclear
    Can someone explain it to me? Esp the last stage - oxidative phosphorylation

    Thank you
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    Hiya,

    Is this for GCSE? In very simple terms it is the process in which the body converts oxygen from the air and glucose from our body's cells into energy which we can use for movement and water and carbon dioxide are created as waste products. Most likely you need to know it in more detail though!

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    (Original post by VioletPhillippo)
    Hiya,

    Is this for GCSE? In very simple terms it is the process in which the body converts oxygen from the air and glucose from our body's cells into energy which we can use for movement and water and carbon dioxide are created as waste products. Most likely you need to know it in more detail though!

    Thanks for replying
    It's actually for A2!



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    (Original post by spiritless98)
    So I've been trying to teach myself respiration (not been taught in class yet) and the ocr textbook is very unclear
    Can someone explain it to me?
    Thank you
    There are 4 main steps in aerobic respiration.

    1. Glycolysis.
    This turns glucose (6carbons) into two lots of pyruvate (2 x 3carbons) in the cell cytoplasm.
    Spoiler:
    Show
    Glucose (6 carbons)
    | <uses up 2ATP
    Hexose bisphosphate (6C)
    |
    2 x triose phosphate (3 carbons each)
    |> makes 4 ATP and 2 reduced NAD in total because there are 2TP
    2 x pyruvate (3C each)
    2. The link reaction
    Which turns pyruvate into acetyl coenzyme A, in the mitochondrial matrix.
    Spoiler:
    Show
    REMEMBER TWO MOLECULES OF PYRUVATE ARE MADE FOR EVERY ONE GLUCOSE MOLECULE, SO MULTIPLY ANY PRODUCTS BY TWO E.G. NADH X 2.
    Pyruvate
    |> makes CO2 and reduced NAD
    Acetate
    |<combined with coenzyme A
    Acetyl CoA
    3. The Krebs cycle
    This turns oxaloacetate into citrate in the matrix.
    Spoiler:
    Show
    REMEMBER TWO MOLECULES OF ACETYL COA ARE MADE FOR EVERY ONE GLUCOSE MOLECULE, SO MULTIPLY ANY PRODUCTS BY TWO FOR THE OVERALL PRODUCTS PER GLUCOSE MOLECULE.
    Acetyl CoA combines with (4C) oxaloacetate to form citrate.
    Citrate>intermediates>oxaloaceta te>citrate etc...
    Many things are made/used here.
    1 CoA (reused in next link reaction)
    Oxaloacetate (regenerated for next Krebs cycle)
    2CO2 (waste)
    1ATP (for energy)
    3 reduced NAD (to oxidative phosphorylation)
    1 reduced FAD (to oxidative phosphorylation)
    4. Oxidative phosphorylation
    Which produces ATP and water across the inner membrane of the mitochondria.
    Spoiler:
    Show
    In oxidative phosphorylation, hydrogen atoms, from reduced NAD and reduced FAD split into protons (H+) and electrons.Electrons move along the electron transport chain (aided by electron carriers) and lose energy on the way. This energy pumps H+ from the matrix to the inter membrane space.There's now an electrochemical gradient of H+ ions, so they move down the gradient (chemiosmosis) through the channel associated with ATP synthase, which causes ADP+Pi->ATP.At the end of the electron transport chain, H+, electrons and oxygen from blood combine to form water, so oxygen is the final electron acceptor.
    Start simply, then add in more detail.
 
 
 
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