And so once oxygen is actually bound to the hemoglobin and that space closes in, and the two three BPG shown in purple can no longer actually bind onto our hemoglobin. So, once again, two three BPG only binds to deoxy hemoglobin proteins found within the red blood cells. Now, once the two three BPG actually binds to our deoxy hemoglobin, it makes the protein much less likely to actually bind to other oxygen molecules. And what that means is a high concentration of two three BPG inside the red blood cells shifts the entire oxygen hemoglobin. So, dissociation curve to the right. And to see what we mean by that, let's take a look at the following diagram.