Structure Outer and Inner Membranes

Mitochondria are the energy powerhouses of cells. Mitochondrial membranes play an essential and unique function to generate energy. Mitochondria have two specialized membranes (outer and inner membranes), which are very different. Inside the inner membrane is the matrix, and the space between the outer and inner mem- 

Molecular and Biochemical Toxicology, Fourth Edition, edited by Robert C. Smart and Ernest Hodgson Copyright 2008 John Wiley Sons, Inc. 

2 Generating High-Energy Electrons (TCA Cycle, Fatty Acid Oxidation, FADH2, and NADH) 

3 Respiratory Chain (Complex I, II, III, and IV, Ubiquinone, Cytochrome c, Proton Pump, Membrane Potential, Proton Motive Force) 

Step 1 Complex I. Complex I is the NADFI dehydrogenase complex consisting of more than 40 polypeptides. It accepts electrons from NADFI and passes them through flavin and iron-sulfur centers to the electron carrier ubiquinone (Q). By using one NADFI (= 2 electrons), this reaction pumps the 4 protons (2 protons/ electron) from the matrix to the intermembrane space. 

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