Carbon dioxide and membrane transport question

[eagles]

Carbon dioxide engages in passive transport from body cells to red blood cells.
It is transported predominantly in the form of HCO₃^-.
Carbon dioxide produced in cells moves into capillaries and then into the red blood cells, where it is acted on by the enzyme carbonic anhydrase for a conversion to HCO₃^-.
The HCO₃^- ions produced in the red blood cells move back into the plasma.

How does the conversion of CO₂ to HCO₃- ions in red blood cells assist the removal of CO₂ from the body?

I'm unsure how to answer this question and would really like your help! Cheers x)

[eagles]

Well, wasn't that a tough question? 

I have since found the answer:

Carbon dioxide can continually be diffused into red blood cells from the plasma when the carbon dioxide is readily converted to bicarbonate ions (since if carbon dioxide remains in the pure form in red blood cells, heaps of carbon dioxide will eventually be needed to create a concentration gradient; also note that active transport is too laborious for the transport of carbon dioxide gas).