And the way that this takes place is we have a special ion exchange protein found within our membrane of the red blood cells. And what happens is a single bicarbonate ion leaves the cell and enters the blood plasma because it can easily dissolve inside the blood plasma because unlike CO2, bicarbonate has a full negative charge, it is polar. But at the same time that our bicarbonate ion leaves the cell, in order to maintain an electrically neutral state, in order to not build any charge, we need to transport another particle, another atom that contains a negative charge into the cell. Because if one negative charge exits the cell, we have to basically take a negatively charged atom and make it go into the cell to maintain an electrically neutral state, because we do not actually want to affect the electrochemical gradient that exists between the inside of the red blood cell and the outside the blood plasma. So we essentially exchange a single bicarbonate ion for a single chloride ion. And this is what we call the chloride shift.