Question

Affinity of CO for haemoglobin as compared to $O_2$ is

• A. Two times
• B. Twenty times
• C. $100$ times
• D. $200$ times

Answer 1

The correct option is D $200$ times

Carbon monoxide has 200 times higher binding affinity to the iron moiety in the haeme group of the haemoglobin. It destroys the oxygen-binding and oxygen-carrying capacity of the haemoglobin because it binds with it irreversibly to form the compound called the carboxyhemoglobin. This compound binds to the available oxygen as well but does not release it to the tissues. Because of this, the body tissues suffocate in a deficiency of the oxygen. This process is called carbon monoxide poisoning, that results in death.

Hence, the correct answer is '200 times'.