Biology Forums - Study Force

what would hypothetically happen to the amount of ATP available to a cell if the entire Cori cycle were to occur and remain within a single cell such as a muscle cell?

It would drop way down, probably lethally pretty quickly. The conversion back consumes more than is liberated (creating the lactate releases 2, moving it back to glucose consumes 6).

That is why it is primarily used in nature just for muscle movement when things have gotten a bit on the anaerobic side - the muscle can get decent ATP without having to use local oxygen and turning the lactic acid over into the Krebs cycle, with the conversion back to glucose usually taking place in the liver.

The Cori cycle (also known as Lactic acid cycle), named after its discoverers, Carl Cori and Gerty Cori, refers to the metabolic pathway in which lactate produced by anaerobic glycolysis in the muscles moves to the liver and is converted to glucose, which then returns to the muscles and is converted back to lactate.

Instead of accumulating inside the muscle cells, lactate produced by anaerobic fermentation is taken up by the liver. This initiates the other half of the Cori cycle. In the liver, gluconeogenesis occurs. From an intuitive perspective, gluconeogenesis reverses both glycolysis and fermentation by converting lactate first into pyruvate, and finally back to glucose. The glucose is then supplied to the muscles through the bloodstream; it is ready to be fed into further glycolysis reactions.

Overall, the glycolysis part of the cycle produces 2 ATP molecules at a cost of 6 ATP molecules consumed in the gluconeogenesis part. Each turn of the cycle must be maintained by a net consumption of 4 ATP molecules. As a result, the cycle cannot be sustained indefinitely. The intensive consumption of ATP molecules indicates that the Cori cycle shifts the metabolic burden from the muscles to the liver