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Saturday, September 26, 2009

krebs cycle

AKA the Tricarboxylic Acid (TCA) Cycle or the. Krebs CycleThe Citric Acid Cycle is one of 3 stages of cellular respiration. The others are glycolysis and electron transport/oxidative phosphorylation. The big picture: Glycolysis breaks 1 glucose into 2 pyruvate, producing 6 ATP. Pyruvate is used to make acetyl-CoA, the starting product for the citric acid cycle. Each turn of the cycle oxidizes 1 pyruvate, so it takes 2 turns to completely oxidize 1 glucose. Two turns produce 8 NADH, 2 FADH2, and 2 ATP. NADH and FADH2 are then oxidatively phosphorylated, resulting in 28 more ATP. The 3 stages together produce 30 to 38 ATP. The net reaction for the 8 proper steps of the cycle:Acetyl-CoA + 3 NAD+ + FAD + GDP + Pi + 2H20 <==> CoASH + 3 NADH + FADH2 + GTP + 2CO2 + 3H+ DG؛' = -49 kJ/mol DG ~ -115 kJ/mol

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