Assertion : At the tissue level, 70 percent of `CO_(2)` formed from contabolism is trapped as bicarbonate in the RBCs.
Reason : At tissue level, carbonic anhydrase in RBCs facilites the formation of `CO_(2)` and `H_(2)O` from bicarbonate.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true and reason is not the correct explanation of assertion
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

C

Explanation

RBCs contain a very high concentration of carbonic anhydrase enzyme which facilitates the following reaction in both direactions.
`CO_(2) + H_(2)Ooverset("carbonic anhydrase")hArrH_(2)CO_(3)hArroverset("carbonic anhydrase")hArr HCO_(3)^(-)+H^(+)`
At the tissues site where partial pressur of `CO_(2)` is high due to catabolism, `CO_(2)` diffuses into blood (RBCs and plasma) and forms `HCO_(3)^(-)` and `H^(+)`. At the alveolar site where `PCO_(2)` is low, the reaction proceeds in the oppsite direction leading to the formation of `CO_(2)` and `H_(2)O`.