Oxygen continuously diffuses into plants in animals, it enters the body through the respiratory system. The electron transport chain (Figure 1) is the last component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water. The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH 2 to molecular oxygen. The current of hydrogen ions powers the catalytic action of ATP synthase, which phosphorylates ADP, producing ATP. Therefore, a concentration gradient forms in which hydrogen ions diffuse out of the matrix space by passing through ATP synthase. This causes hydrogen ions to accumulate within the matrix space. Rather, it is derived from a process that begins with moving electrons through a series of electron transporters that undergo redox reactions: the electron transport chain. However, most of the ATP generated during the aerobic catabolism of glucose is not generated directly from these pathways. ![]() You have just read about two pathways in cellular respiration-glycolysis and the citric acid cycle-that generate ATP. In the process, protons are pumped from the mitochondrial matrix to the intermembrane space, and oxygen is reduced to form water.\) ![]() The electron transport chain: The electron transport chain is a series of electron transporters embedded in the inner mitochondrial membrane that shuttles electrons from NADH and FADH 2 to molecular oxygen. The electron transport chain is present in multiple copies in the inner mitochondrial membrane of eukaryotes and the plasma membrane of prokaryotes. The electron transport chain is an aggregation of four of these complexes (labeled I through IV), together with associated mobile electron carriers. This requirement for oxygen in the final stages of the chain can be seen in the overall equation for cellular respiration, which requires both glucose and oxygen.Ī complex is a structure consisting of a central atom, molecule, or protein weakly connected to surrounding atoms, molecules, or proteins. Electrons are passed rapidly from one component to the next to the endpoint of the chain, where the electrons reduce molecular oxygen, producing water. Electron transport is a series of redox reactions that resemble a relay race. ![]() The electron transport chain is the final component of aerobic respiration and is the only part of glucose metabolism that uses atmospheric oxygen. Complex IV reduces oxygen the reduced oxygen then picks up two hydrogen ions from the surrounding medium to make water.Complex III pumps protons through the membrane and passes its electrons to cytochrome c for transport to the fourth complex of proteins and enzymes.Ubiquinone (Q) accepts the electrons from both complex I and complex II and delivers them to complex III.Complex II receives FADH 2, which bypasses complex I, and delivers electrons directly to the electron transport chain.Complex I establishes the hydrogen ion gradient by pumping four hydrogen ions across the membrane from the matrix into the intermembrane space.There are four protein complexes (labeled complex I-IV) in the electron transport chain, which are involved in moving electrons from NADH and FADH 2 to molecular oxygen.Oxidative phosphorylation is the metabolic pathway in which electrons are transferred from electron donors to electron acceptors in redox reactions this series of reactions releases energy which is used to form ATP.
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