Paper 1 · People, Development & Environment
UGC NET 25th June 2025 Shift 1
What is the correct sequence, from initial to final, of blue baby disease, methemoglobinemia, in human infants?
- 1. Conversion of nitrate ions to nitrite ions by microorganisms in human body
- 2. Oxidation of ions from Fe(II) to Fe(III) in hemoglobin by nitrite ions.
- 3. Consumption of nitrate polluted water
- 4. Forming of abnormal hemoglobin called methemoglobin
A3, 2, 1, 4
B3, 1, 2, 4 ✓ Correct
C1, 4, 2, 3
D1, 3, 2, 4
Answer: B
Explanation
★The disease begins when nitrate polluted water is consumed, after which microorganisms turn nitrate into nitrite. The nitrite then oxidises iron in haemoglobin from the two plus to the three plus state, and this finally produces the abnormal haemoglobin called methemoglobin. The order is therefore 3, 1, 2, 4.
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