chloride shift act as a buffer.Explain

Bicarbonate in the red blood cell (RBC) exchanging with chloride from plasma.

The underlying properties creating the chloride shift are the presence of carbonic anhydrase within the RBCs but not the plasma, and the permeability of the RBC membrane to carbon dioxide and bicarbonate ion but not to hydrogen ion. Exchange of bicarbonate for chloride ions across the RBC membrane maintains the macroscopic electroneutrality of the cell. The net direction of bicarbonate-chloride exchange (bicarbonate out of RBCs in the systemic capillaries, bicarbonate into RBCs at pulmonary capillaries) proceeds in the direction that decreases the sum of the electrochemical potentials for the chloride and bicarbonate ions being transported.

The reaction:

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