The toxic effect of carbon monoxide is due to its greater affinity for haemoglobin as compared to oxygen approximately by

Options

A. `200` times
B. `1000` times
C. `2` times
D. `20` times

Answer

**Step-by-Step Solution:**

1. **Understanding Hemoglobin's Function**: Hemoglobin is a protein in red blood cells responsible for transporting oxygen from the lungs to the rest of the body and returning carbon dioxide from the body back to the lungs.

2. **Binding of Gases**: Hemoglobin can bind to different gases:
- It binds with oxygen to form oxyhemoglobin.
- It binds with carbon dioxide to form carbaminohemoglobin.
- It binds with carbon monoxide to form carboxyhemoglobin.

3. **Comparative Affinity**: The affinity of hemoglobin for these gases varies:
- It has the least affinity for carbon dioxide.
- It has a higher affinity for oxygen compared to carbon dioxide.
- It has the highest affinity for carbon monoxide compared to both oxygen and carbon dioxide.

4. **Quantifying Affinity**: The question asks for the approximate factor by which carbon monoxide's affinity for hemoglobin exceeds that of oxygen. Research indicates that carbon monoxide binds to hemoglobin with an affinity that is approximately 200 times greater than that of oxygen.

5. **Conclusion**: Therefore, the toxic effect of carbon monoxide is primarily due to its significantly higher affinity for hemoglobin compared to oxygen, which is approximately 200 times greater.

**Final Answer**: The toxic effect of carbon monoxide is due to its greater affinity for hemoglobin as compared to oxygen, approximately by 200 times.

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