Question

Assertion :$C{O}_2$ is carried in the plasma mainly as $HC{O}_3^{-}$ ions. Reason: Zinc-containing enzyme carbonic anhydrase of RBCs catalyses the formation of $HC{O}_3$ ions that enter plasma.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

About 7% of carbon dioxide is transported, dissolved in plasma and rest by RBC and 70% in the form of bicarbonates in plasma. It is more soluble in blood than oxygen. It combines with haemoglobin to form carbaminohemoglobin which dissociate to release carbon dioxide when it reaches the lungs. Carbon dioxide combines with water and forms carbonic acid in presence of carbonic anhydrase in RBC. Zinc-containing enzyme carbonic anhydrase of RBC's catalyses the formation of bicarbonate ions that enter plasma. The carbonic acid dissociates to form bicarbonate ions which are exchanged with chloride ions in the plasma.

So, the correct answer is option A.