text: can someone explain the steps of the kreb cycle?   the krebs cycle occurs in the mitochondrial matrix. pyruvate produced in the glycolysis is first decarboxylated to yield acetyl-coa. the acetyl-coa combines with oxaloacetate to yield citrate. citrate is then converted to isocitrate. isocitrate is then converted to a-ketoglutarate (first co2 is lost and the first nadh is produced). a-keto is converted to succinyl-coa (co2 produced). at this point the rest of the cycle is to regenerate oxaloacetate. the succinyl-coa is converted to succinate (producing gtp) which is converted to fumarate (produces fadh2). fumarate is converted to malate and finally to oxaloacetate (nadh produced). krebs cycle produces a total of 1 gtp, 1 fadh2 and 3 nadh. the fadh2 and nadh enter the electron transport chain. for each molecule of glucose there will be 2 turns of the cycle.