Figure 1 FLASH ANIMATION

In order to view this animation you need to have installed the Flash Player plugin. Download plugin.

Figure 1 | OXPHOS system in mammalian mitochondria.  Electrons (e^-) from carbon oxidations (step 1 and dotted lines) are transferred via NADH (step 2) into OXPHOS complex I (step 3), which is embedded in the lipid bilayer of the inner mitochondrial membrane (IMM), then transported to coenzyme Q (CoQ) (step 4). Some electrons from organic-acid oxidations are transferred, via other flavin-containing enzyme complexes (step 5), directly to CoQ. CoQ delivers electrons via complex III (step 6) and cytochrome c (Cyt c) (step 7) to the final electron acceptor complex IV (step 8). Here, oxygen is reduced to water. The electrons lose free energy at each transfer step, and in complexes I, III and IV, the energy is harnessed and coupled to the movement of H⁺ (step 9 and dashed lines) from the mitochondrial matrix to the intermembrane space (IMS). The proton gradient thus generated is used for the production of ATP by complex V (step 10). Except for complex II, all complexes contain some proteins encoded by the mitochondrial genome and others encoded by the nuclear genome. The number of subunits for each complex is indicated. (CN, cyanide; FMN, flavin mononucleotide; mt, mitochondrial.) (Modified with permission from Ref. 123.)
Animated online

Please close this window to return to the main article.