Question

The major bulk of carbon dioxide($C{O}_2$) in our body is present in the blood as

• A. Bicarbonate in blood plasma and RBCs
• B. 70 % Carbamino compounds and 30 % as Bicarbonate
• C. Carbamino- haemoglobin in RBCs
• D. Gaseous form in blood plasma

Answer 1

The correct option is A Bicarbonate in blood plasma and RBCs

The majority of carbon dioxide molecules are carried as part of the bicarbonate buffer system. In this system, carbon dioxide diffuses into the red blood cells. Carbonic anhydrase within the red blood cells quickly converts the carbon dioxide into carbonic acid. Carbonic acid is unstable, that immediately dissociates into bicarbonate ions and hydrogen ions. Since carbon dioxide is quickly converted into bicarbonate ions, this reaction allows for the continued uptake of carbon dioxide into the blood, down its concentration gradient.