- The Krebs Cycle
- Occurs in the mitochondrial matrix. Acetyl CoA (2C) combines with oxaloacetate (4C) to form citrate (6C); CoA-SH is released for reuse.
- Citrate is progressively decarboxylated and dehydrogenated (via isocitrate, alpha-ketoglutarate, succinyl CoA, succinate, fumarate, malate) back to oxaloacetate, releasing CO₂ and reducing NAD⁺/FAD⁺ to NADH₂/FADH₂ at several steps; one step produces ATP directly by substrate-level phosphorylation.
- Total yield per glucose (2 turns of the cycle): 2 ATP, 6 NADH₂, 2 FADH₂, 4 CO₂.