Now, the other effect that the binding of carbon monoxide has on hemoglobin curve is the following. Notice that the blue curve is found much higher than the red curve. We see that there is a drop in our curve. The question is why? Why does this take place, and what effect does it have on our tissues? Well, basically, once carbon monoxide actually binds onto one of the heme groups of hemoglobin, it decreases the amount of oxygen that the hemoglobin can actually bind.