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4 Cards in this Set
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What are the three main stages of the aerobic system |
Glycolysis Krebs cycle Electron transport chain |
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Glycolysis |
It takes place in the sacroplasm of the muscle cell. Glycolysis is the breakdown of glucose into pyruvic acid. For every molecule of glucose undergoing glycolysis, a net of two molecules of ATP is formed. Before the pyruvic acid produced in glycolysis can enter the next stage, it splits into two acetyl groups and is then carried into the Krebs cycle by coenzyme A |
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Krebs cycle |
Acetyl coenzyme A combines with oxaloacetic acid, forming citric acid. Hydrogen is removed from citric acid and the rearranged form of citric acid undergoes "oxidative carboxylation". The carbon forms carbon dioxide, which is transported to the lungs and breathed out, and the hydrogen is taken to the electron transport chain. The reactions that occur result in the production of two molecules of ATP Fats can also enter the Krebs cycle. Stored fat is broken down into glycerol and free fatty acids for transportation by the blood. These fatty acids then undergo a process called beta oxidation, whereby they are converted into acetyl coenzyme A. From this point on, fat metabolism follows the same path as glycogen metabolism. More ATP can be made from one molecule of fatty acids than one molecule of glucose, which is why in long duration fatty acids will be the predominant energy source. |
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Electron transport chain |
Hydrogen is carried to the electron transport chain by hydrogen carriers. This occurs in the cristae of the mitochondria. The hydrogen splits into hydrogen ions and electrons and they are charged with potential energy, the hydrogen ions are oxidized to form water, while the hydrogen electrons provide the energy to re-synthesise ATP. throughout this process 34 molecules of ATP are formed |
