So notice as we go to the right, along the x axis, we increase the concentration. And as we go up along the y axis, we increase the velocity or the rate of activity of that enzyme. Now, this slope, shown in purple basically describes the relationship between the concentration of substrate as well as the velocity or rate of activity of our enzyme. So notice initially we have a relatively linear relationship between the concentration and the velocity. So initially, as we increase the concentration, our rate or velocity also increases pretty much linearly. Now eventually we reach this point here and this point basically represents something known as Km.