Cellular Respiration Essay

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Introduction Aerobic cellular respiration is the basis of energy for most living organisms. Adenosine triphosphate (ATP) is the fuel utilized for life. ATP is manufactured in a series of reactions that begin in the cytoplasm of the cell where glucose by the process of glycolysis is converted to pyruvate molecules. Pyruvates are then converted through an oxidative process to create acetyl-CoA. Acetyl-CoA is transported within the cell to the mitochondrion, a specialized organelle where acetyl-CoA converts into ATP. Aerobic cellular respiration is a more efficient process producing 38 molecules of ATP compared to the anaerobic process that produces 2 ATP molecules. This sequence of reactions also creates the by-products of water and carbon dioxide (CO2). The by-product carbon dioxide was the compound measured for this experiment. As carbon dioxide is released into the water through the respiration of the crayfish it is converted into carbonic acid shown below. CO2 + H20  H2CO3 As more carbon dioxide was released into the water surrounding the crayfish the water became more acidic. We could then measure the amount of CO2, by measuring the amount of a basic solution, in this case sodium hydroxide (NaOH) to neutralize the acid. We used the pH indicator phenolphthalein, which is colorless in acidic solutions and turns red in basic solutions. The more carbon dioxide in the water the more sodium hydroxide was needed to neutralize the solution. This experiment focused on the effects of size in relation to respiration. The results were compiled according to the size of the crayfish. As a general trend larger organisms create more carbon dioxide although they use less per gram of tissue (Davidson, 1956). It has been observed that smaller organisms have higher metabolic rates than larger organisms of the same species. This is not well understood,
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