And that's because if we have lots of B by increasing or decreasing B, that basically does nothing to the rate. But if we have very little A, then changing A will actually have a drastic effect on the rate of that reaction. And so that's exactly why this case is a pseudo first order. It's actually a second order reaction that behaves as if it was a first order. So in the next lecture we're going to begin our discussion on enzyme kinetics. And the main important point in this lecture was to basically realize how enzymes actually affect the rate law and the rate constant.