Carbon dioxide is produced continuously by respiring cells. It passes by diffusion into red blood cells and splits into hydrogen ions ($\text{H}^+$) and hydrogen carbonate ions ($\text{HCO}_3^-$). $\text{HCO}_3^-$ then moves out of the cell in exchange for chloride ions ($\text{Cl}^-$) in the chloride shift. What is the role of the chloride shift?
- AIt helps to maintain a neutral pH in the red blood cell by acting as a buffer.
- BIt maintains a balance of positive and negative charge between the cell and the plasma.
- CIt causes the oxygen dissociation curve to shift to the left, releasing more oxygen.
- DIt prevents carbon dioxide combining with haemoglobin, allowing haemoglobin to combine with oxygen.