Energy Capture and Metabolism in Living Organisms

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5. Describe the processes of energy capture and metabolism for living organisms and how they relate to one another. Be sure to address photosynthesis, glycolysis, fermentation, and respiration. Photosynthesis is one process of energy capture for living organisms. The formula for photosynthesis is 3CO2 + 6H2O + light  C3H6O3 + 3O2 + 3H2O. Basically, during this process, light energy is captured and converted into chemical energy, but it goes much deeper than that. First, light is captured by chloroplasts that contain pigments that capture different photons of light and then reflect different colors. The pigments include: chlorophyll, which absorbs blue and red wavelengths but reflect green; phycobilins, which absorbs blue, green, and yellow, …show more content…

This process may also be known as the Kreb’s Cycle, or the Tricarboxylic Acid Cycle (TCA). Coenzyme A and Acetyl CoA feed into the TCA cycle to power it. First, pyruvate is transported into the matrix by Pyruvate Dehydrogenase and precedes the TCA cycle. Coenzyme A forms the high-energy bonds with the organic acids, and acetyl CoA is formed by pyruvate dehydrogenase. The purpose of the TCA cycle is to metabolize Acetyl CoA and conserve energy produced in the forms of other coenzymes such as NADH and FADH2. During the Kreb’s Cycle, many phases occur and during each phase, new products are formed or released. From TCA-1 ot TCA-4, 2 NADH are formed and 2 CO2 are released. During TCA-5, ATP is formed, and during TCA-6, FADH2 is formed. Finally, during TCA-8, NADH is formed and OAA is regenerated. The total numbers of products per acetyl CoA are: 2 CO2, 3 NADH, 1 FADH2, and 1 ATP. The numbers of products per glucose are: 4 CO2, 6 NADH, 2 FADH2, and 2 ATP. Specific enzymes exist for this process as well. First, Acetyl CoA is changed to Citrate by Citrate Synthase, then Citrate is changed to Isocitrate by Aconitase. Isocitrate is changed to α-Ketoglutarate by Isocitrate Dehydrogenase, and α-Ketoglutarate is changed to Succinyl CoA by α-Ketoglutarate Dehydrogenase. Succinyl CoA is changed to Succinate by Succinyl CoA Synthase, and Succinate is changed to Fumarate by Succinate Dehydrogenase. Fumarate is then changed to Malate by Fumarate Hydratase, and finally, Fumarate is changed Oxaloacetate by Malate Dehydrogenase. Although Acetyl CoA and glucose may feed into this process, most energy comes from the coenzymes. Oxidative Phosphorylation takes place after the Kreb’s Cycle. This process occurs within the inner membrane of the mitochondria. Oxidative phosphorylation creates a concentration gradient that requires energy to push all the

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