But now, instead of using NADH, we're using NAD plus because we basically want to oxidize the malade back into oxyloacetate, producing that reduced version of the NAD molecule. So let's take a look at step two. Now, remember, in step one, the entire goal was to use the highly exergonic process of the hydrolysis of ATP to basically drive the endergonic process of the attachment of the CO2 molecule onto that Pyruvate. So we saw that the carboxylation process is actually an endergonic process. Now, that implies if carboxylation requires energy, that means decarboxylation actually releases energy. And that's important in this step because what happens in this step is this oxalo acetate is transformed into phosphorinopyruvate.