Final answer:
Oxaloacetate formed from citrate through ATP-citrate lyase is reused in the citric acid cycle to form citrate, allowing the cycle to continue. It results in the production of energy intermediates and is also involved in lipogenesis, where it eventually becomes pyruvate to facilitate fatty acid synthesis.
Step-by-step explanation:
When oxaloacetate is generated by the cleavage of citrate by ATP-citrate lyase, it plays a vital role in the citric acid cycle and lipogenesis. In the citric acid cycle, oxaloacetate reacts with an incoming acetyl group from acetyl CoA, yielding citrate. This citrate then goes through a series of reactions that transform it back into oxaloacetate, allowing the cycle to run continuously as long as reactants are available.
This transformation releases two carbon dioxide molecules and produces one ATP (or GTP), one FADH2, and three NADH, which enter the oxidative phosphorylation system. During lipogenesis, oxaloacetate in the cytoplasm is converted into malate, and then back into pyruvate to cross the mitochondrial membrane, while the accompanying acetyl CoA is used for fatty acid synthesis through the formation of malonyl CoA.