Evolution of Cellular Respiration

Evolution of Cellular Respiration - ATP can be made in...

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Evolution of Cellular Respiration Early cells probably fermented organic molecules in the oceans. Today, nearly all organisms show some form of fermentation which indicates that it evolved early in evolutionary history. Evolution typically operates by building upon or adding to what is already there. Aerobic respiration appears to have been added to fermentation. Summary Glycolysis Two ATP molecules are used to phosphorylate and activate glucose . Two hydrogen atoms are removed by NAD + forming 2 NADH. Four ATP molecules are produced by substrate-level phosphorylation . The net yield of ATP is two; two are used and four are produced. Fermentation Fermentation is needed to regenerate NAD + from NADH so that at least some
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Unformatted text preview: ATP can be made in glycolysis. Electrons from NADH are added to pyruvate ( reduction ) to produce alcohol (plants, yeast) or lactate (animals, bacteria) Aerobic Respiration Aerobic respiration occurs when oxygen is available. pyruvate → CO 2 + H 2 O It occurs in the mitochondrion . NAD + and FAD carry electrons to the electron transport system. In the electron transport system, NADH and FADH 2 are used to produce ATP as electrons are passed from one carrier to another. Eventually the electrons combine with hydrogen ions and oxygen ( reduction ) to form water . Click the icon (left) to see an enlarged, color version of the diagram above....
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Evolution of Cellular Respiration - ATP can be made in...

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