Question

About 30% of $C{O}_2$ is transported as

• A. Carbamino compounds
• B. Bicarbonates of Na and K
• C. Carboxyhaemoglobin
• D. Oxyhaemoglobin

Answer 1

Answer: (A)

In blood CO${}_2$ is transported in three ways.

1. Dissolved carbon dioxide - Carbon dioxide dissolves in the intracellular fluid of red blood cells. This accounts for about 5% of the total carbon dioxide released at the lungs.

2. Carbamino-Hb -The compound formed when the carbon dioxide combines with hemoglobin. This reaction releases oxygen, which becomes available for tissue metabolism. This accounts for about 21% of the carbon dioxide carried from the tissues.

3. Bicarbonate - About 63% of the carbon dioxide is transported to tissue cells in the form of bicarbonate (HCO3-).

Thus, option A is correct.