Well, by the action of an enzyme known as nucleotide diphosphokinase. This enzyme actually catalyzes the transfer of a phosphoryl group from the GTP onto an ADP to form the ATP and this GDP. So in this process we utilize the GTP form in step five of the citric acid cycle to generate ATP molecules that can be used by a variety of processes inside our body. So once again, we see that the unstable and high in energy thio esther bond in sucaved to release the coenzyme A and also release free energy. And that free energy is then used to power the endergonic process of attaching of a sporal group onto the GDP to form the GTP. And this is catalyzed by succinct coenzyme asynthetase.