Question

Which gas from the following will mix with haemoglobin of blood and affect the oxygen supply to various parts of body?

• A. $C{O}_2$
• B. $NO$
• C. $CO$
• D. $S{O}_2$

Answer 1

The correct option is C $CO$

The binding of oxygen is affected by molecules such as carbon monoxide $\left(CO\right)$. $CO$ competes with oxygen at the heme binding site. Haemoglobin binding affinity for $CO$ is 250 times greater than its affinity for oxygen, which means that small amounts of $CO$ dramatically reduce the ability of haemoglobin to transport oxygen. Since $CO$ is a colourless, odourless and tasteless gas, and poses a potentially fatal threat, detectors have become commercially available to warn of dangerous levels in residences. When haemoglobin combines with $CO$, it forms a very bright red compound called carboxyhaemoglobin.