So the chloride shift takes place to maintain a balance of electrical charge between the inside of the red blood cell, the cytoplasm portion, and the outside environment, the blood plasma. So about 90% of the carbon dioxide exists in its bicarbonate ion state inside the blood plasma. About 5% exist dissolved inside our blood plasma at CO2. And the rest of it is actually bound to hemoglobin. So hemoglobin doesn't only bind oxygen. It can also bind a tiny bit of carbon dioxide.