Q."Aerobic respiration is more efficient than anaerobic respiration." Comment on the above statement.
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Start your 14-day free trial to unlock the full solution →Aerobic respiration extracts far more ATP from each glucose molecule than anaerobic respiration, because it fully oxidises glucose to CO2 and water instead of stopping at partially-oxidised, still energy-rich end products.
Both aerobic and anaerobic respiration begin with the same first step, glycolysis, which breaks glucose down into pyruvate in the cytoplasm, yielding a net gain of only 2 ATP. What happens next determines the huge difference in efficiency. In aerobic respiration, in the presence of oxygen, the pyruvate is transported into the mitochondria, where it is completely oxidised through the Krebs cycle and the electron transport chain, ultimately being broken all the way down to carbon dioxide and water. This complete oxidation, made possible by oxygen acting as the final electron acceptor, releases the vast majority of the chemical energy stored in the glucose molecule, generating roughly 36 to 38 ATP molecules in total per glucose. In anaerobic respiration, without oxygen, the pathway stops at glycolysis; pyruvate is instead converted into ethanol and CO2, or lactic acid, without any further oxidation. These end products (ethanol, lactic acid) still contain most of the chemical energy that was originally in the glucose molecule, energy that is simply not extracted as ATP. As a result, ana …
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