Also known as HANS'S KREB cycle or TRICARBOXYLIC CYCLE. Citric Acid Cycle has eight steps: 1. Formation of Citrate: The first reaction of the cycle is the condensation of acetyl-CoA with oxaloacetate to form citrate, catalyzed by citrate synthase. Citrate, a tricarboxylic acid, is the first stable product. 2. Formation of Isocitrate via cis-Aconitate: The enzyme aconitase (more formally, aconitate hydratase) catalyzes the reversible transformation of citrate to isocitrate. 3. Oxidation of Isocitrate to a-Ketoglutarate and CO₂: In the next step, isocitrate dehydrogenase catalyzes oxidative decarboxylation of isocitrate to form a-ketoglutarate. 4. Oxidation of a-Ketoglutarate to Succinyl-CoA and CO₂ 5. Conversion of Succinyl-CoA to Succinate: During the conversion of succinyl-CoA to succinic acid, a molecule of GTP is synthesised. This is a substrate level phosphorylation. 6. Oxidation of Succinate to Fumarate: The succinate formed from succinyl-CoA is oxidized to fumarate by the flavoprotein succinate dehydrogenase. 7. Hydration of Fumarate to Malate: The reversible hydration of fumarate to L-malate is catalyzed by fumarase. 8. Oxidation of Malate to Oxaloacetate: In the last reaction of the citric acid cycle, NAD-linked L-malate dehydrogenase catalyzes the oxidation of L-malate to oxaloacetate.