And so so let's begin with step number two. Now, the entire point of step number two is basically to take the citrate molecule and to prepare it for oxidative decarboxylation that will take place in step three and step four of the citric acid cycle. So in these two steps, we're basically going to produce carbon dioxide molecules, and we're going to abstract those high energy electrons that we're going to use on the electron transport chain. But before steps three and four take place, we have to prepare the citrate molecule. And the way that we prepare that citrate molecule is by actually changing the position of this hydroxyl group. So citrate and isocytrate are actually isomers.