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6.3.7: Electron Transport Chain

  • Page ID
    1485
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    The electron transport chain is located on the inner membrane of the mitochondria, as shown below.

    Figure 6.261.png

    Figure 6.261 The pathways involved in aerobic respiration1

    The electron transport chain contains a number of electron carriers. These carriers take the electrons from NADH and FADH2, pass them down the chain of complexes and electron carriers, and ultimately produce ATP. More specifically, the electron transport chain takes the energy from the electrons on NADH and FADH2 to pump protons (H+) into the intermembrane space. This creates a proton gradient between the intermembrane space (high) and the matrix (low) of the mitochondria. ATP synthase uses the energy from this gradient to synthesize ATP. Oxygen is required for this process because it serves as the final electron acceptor, forming water. Collectively this process is known as oxidative phosphorylation. The following figure and animation do a nice job of illustrating how the electron transport chain functions.

    Figure 6.262.png

    Figure 6.262 Location of the electron transport chain in the mitochondria2

    Web Link

    ETC Animation

    2.5 ATP/NADH and 1.5 ATP/FADH2 are produced in the electron transport chain. Some resources will say 3 ATP/NADH and 2 ATP/FADH2, but these values are generally less accepted now.

    For one molecule of glucose, the preceding pathways produce:

    Glycolysis: 2 NADH

    Transition Reaction: 2 NADH

    Citric Acid Cycle: 6 NADH, 2 FADH2

    Total 10 NADH, 2 FADH2

    Multiply that by the amount of ATP per NADH or FADH2 to yield:

    10 NADH X 2.5 ATP/NADH = 25 ATP

    2 FADH2 X 1.5 ATP/FADH2 = 3 ATP

    Total 28 ATP

    The first video does a nice job of illustrating and reviewing the electron transport chain. Note that it uses 3 ATP/NADH and 2 ATP/FADH2 so the totals from each cycle are different from those listed above. The second video is a great rap video explaining the steps of glucose oxidation.

    Web Links

    Video: Electron Transport (1:43)

    Video: Oxidate it or Love it/Electron to the Next One (3:23)

    References & Links

    1. http://en.Wikipedia.org/wiki/File:CellRespiration.svg

    2. en.Wikipedia.org/wiki/File:Mi...%80%94Etc4.svg

    Videos

    Electron Transport Chain - http://www.youtube.com/watch?v=1engJ...eature=related

    Oxidate it or Love it/Electron to the Next One - http://www.youtube.com/watch?v=VCpNk...response_watch


    This page titled 6.3.7: Electron Transport Chain is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Brian Lindshield via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

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