Question

Which of the following binds with hemoglobin irreversibly?

• A. Carbon dioxide
• B. Carbon monoxide
• C. Ethane
• D. Nitrogen

Answer 1

Answer: (B)

Carbon monoxide

The red blood cells contain hemoglobin and each red blood cell contains nearly 280 million hemoglobin molecules. The hemoglobin molecules transport oxygen from the lungs to the tissues and also transports CO${}_2$ from the tissues to the lungs. However, the affinity displayed by hemoglobin molecules for carbon monoxide is many times greater than oxygen. The presence of even very low levels of carbon monoxide has a profound effect on oxygen transport of the blood. Moreover, the binding of carbon monoxide to hemoglobin is irreversible.