UPSC Prelims 2010·GS1·science-and-technology·science and technology

Excessive release of the pollutant carbon monoxide (CO) into the air may produce a condition in which oxygen supply in the human body decreases. What causes this condition?

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Last updated 23 May 2026, 3:31 pm IST
  1. AWhen inhaled into the human body, CO is converted into CO₂
  2. BThe inhaled CO has much higher affinity for haemoglobin as compared to oxygenCorrect
  3. CThe inhaled CO destroys the chemical structure of haemoglobin
  4. DThe inhaled CO adversely affects the respiratory centre in the brain

Explanation

The correct answer is B because carbon monoxide has a much stronger binding affinity for haemoglobin than oxygen does. In fact, its affinity is about 200 to 250 times higher than that of oxygen. When inhaled, carbon monoxide binds with haemoglobin to form a stable compound called carboxyhaemoglobin. This prevents haemoglobin from picking up and transporting oxygen to the body tissues, leading to a decrease in oxygen supply. Unlike option C, it does not destroy the structure of haemoglobin but rather competes for the same binding site, effectively displacing oxygen.
science-and-technology: Excessive release of the pollutant carbon monoxide (CO) into the air may produce a condition in which oxygen supply in t

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