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Oxidative phosphorylation in the eukaryotic mitochondrion is the best-understood example of this process. The mitochondrion is present in almost all eukaryotes, with the exception of anaerobic protozoa such as Trichomonas vaginalis that instead reduce protons to hydrogen in a remnant mitochondrion called a hydrogenosome .
There are two distinct phases in the pathway. The first is the oxidative phase, in which NADPH is generated, and the second is the non-oxidative synthesis of five-carbon sugars. For most organisms, the pentose phosphate pathway takes place in the cytosol; in plants, most steps take place in plastids. [4]
One such pathway is oxidative phosphorylation (OXPHOS) within the electron transport chain (ETC). Various inhibitors can downregulate the electrochemical reactions that take place at Complex I, II, III, and IV, thereby preventing the formation of an electrochemical gradient and downregulating the movement of electrons through the ETC.
is, in essence, the same as the electron transport chain in chloroplasts. The mobile water-soluble electron carrier is cytochrome c 6 in cyanobacteria, having been replaced by plastocyanin in plants. [8] Cyanobacteria can also synthesize ATP by oxidative phosphorylation, in the manner of other bacteria. The electron transport chain is
Cellular respiration is a vital process that occurs in the cells of all [[plants and some bacteria ]]. [2] [better source needed] Respiration can be either aerobic, requiring oxygen, or anaerobic; some organisms can switch between aerobic and anaerobic respiration. [3] [better source needed]
This process lowers the efficiency of photosynthesis, potentially lowering photosynthetic output by 25% in C 3 plants. [1] Photorespiration involves a complex network of enzyme reactions that exchange metabolites between chloroplasts , leaf peroxisomes and mitochondria .
The overall process of creating energy in this fashion is termed oxidative phosphorylation. The same process takes place in the mitochondria, where ATP synthase is located in the inner mitochondrial membrane and the F 1-part projects into the mitochondrial matrix. By pumping proton cations into the matrix, the ATP-synthase converts ADP into ATP.
Coupling with oxidative phosphorylation is a key step for ATP production. However, in specific cases, uncoupling the two processes may be biologically useful. The uncoupling protein, thermogenin —present in the inner mitochondrial membrane of brown adipose tissue —provides for an alternative flow of protons back to the inner mitochondrial ...