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Unformatted text preview: finity (lower
redox potential) and donate them to molecules with a higher electron affinity (higher
redox potential). This set of protein complexes is called the electron transport chain.
(2) NADH and FADH2 transfer their high energy electrons to elements of the electron
transport chain that have a higher affinity for the electrons than they do. From there,
the electrons are passed through the chain, moving to components with successively
higher electron affinity (higher and higher redox potential). These transfers are
spontaneous, energetically favorable (ÄG < 0).
(3) At three steps in the electron transport chain, the ÄG of electron transfer is
coupled to the energetically unfavorable pumping of several H+ from the
mitochondrial matrix ACROSS THE IMM and into the intermembrane space.
(4) Thus, a pH gradient and a charge gradient develop across the inner
mitochondrial membrane. The pH of the matrix rises, and it becomes negatively
charged relative to the IMS and cytoplasm. The ÄpH across the IMM can be 1-2 pH
units. Remember that because the OMM is leaky to small molecules like protons, the
IMS is essentially continuous with the cytoplasm.
<Oxygen is absolutely essential for electron transport!!!>
(5) When the electrons have...
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This note was uploaded on 06/12/2012 for the course BIOLOGY 231 taught by Professor Petethollenbeck during the Fall '10 term at Purdue.
- Fall '10
- cell biology