In gluconeogenesis, the first step in that process is to transform the Pyruvate molecule into oxyloacetate and the enzyme that catalyzes this step is Pyruvate carboxylase. So Pyruvate carboxylase essentially attaches a carbon dioxide molecule onto that Pyruvate to form oxyloacetate. In the process we essentially break down an ATP to drive this process in this direction. So we see that by attaching a carbon dioxide onto the Pyruvate, we are able to form the oxalo acetate. And that allows us to keep to maintain a specific minimal level concentration of the oxalo acetate within the citric acid cycle, which in turn allows us to maintain a specific level of the other intermediates and that allows all these important processes to continue taking place inside our cells. So for the citric acid cycle to keep up with the energy demands of the cell and the demands of producing all these different types of biological building blocks, the concentrations of the intermediate molecules within the TCA cycle must be regulated.