We essentially take an amino group from another molecule, namely the glutamate. We place it onto oxyloacetate, and that's how we form the aspartate. So in step four, shown here, the oxyloacetate cannot move across the inner mitochondrial membrane. And so a transamination reaction converts it into aspartate. Now, in step five, once we form the aspartate, the aspartate can now flow out of the inner membrane of the mitochondria via an exchange transport system, an antiported system, in exchange for glutamates. So the aspartate flows out and the glutamate actually flows in.