So we know where pyruvate comes from. That comes from the breakdown of glucose. So when we don't have enough glucose in our body, we can actually take that pyruvate and essentially reverse the steps of glycolysis. Now, that's not exactly true, and we'll talk more about that in just a moment, but basically, gluconeogenesis is actually the process by which we take the pyruvate and turn it back into glucose. Now, what about lactate? Well, we know if we're exercising vigorously, our skeleton muscles will begin to produce ATP to actually contract our skeletal muscle.