Question

Which of these gases are mostly transported by binding to hemoglobin?

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

Answer 1

The correct option is D Oxygen

Both oxygen and carbon dioxide are transported by hemoglobin. But, only 20-25$\%$ of carbon dioxide is transported by binding to haemoglobin, about 70$\%$ of it is transported as carbonate ions and around 3$\%$ by simple diffusion. But hemoglobin has a higher affinity for oxygen because of which it can exchange the gases at the alveoli. So, all of it is transported by haemoglobin. Nitrogen and carbon monoxide are not normally transported by the blood.