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Question #126628
The Question
Read the following statements regarding fetal-maternal gas exchange and the properties of Fetal Hemoglobin (HbF). Which of the following statements is INCORRECT?
Options
- A.
HbF exhibits a left-shifted oxygen dissociation curve compared to maternal HbA due to the presence of gamma chains instead of beta chains.
- B.
The reduced affinity of HbF for 2,3-BPG allows it to load oxygen efficiently even at the relatively low pO2 of the placental environment.
- C.
The diffusion of CO2 from fetal to maternal blood induces a Bohr effect in maternal circulation, increasing maternal hemoglobin's affinity for oxygen.
- D.
The Haldane effect in the fetal circulation facilitates the unloading of CO2 as HbF binds to the oxygen transferred from the mother.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Haldane_Effect|Oxyhemoglobin_Dissociation_Curve|Nucleic_Acid_Structural_Stability
Why This Question Is Tricky
Examiner Levers
Negative Thinking
Uses "NOT", "EXCEPT", or "INCORRECT" to flip the logic gate.
Difficulty Boost : +2Logical Assertion
Tests the causal relationship between two true statements.
Difficulty Boost : +4Common Mistakes
Conceptual Pivot: Students often memorize that the 'Bohr effect facilitates oxygen transfer' but fail to apply the directional vector.
The trap exploits this by stating the Bohr effect 'increases' maternal O2 affinity.
For O2 to move from mother to fetus, maternal Hb must LOSE its affinity for O2 (right shift/release) while fetal Hb maintains a HIGH affinity (left shift/loading).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Breathing and Exchange of Gases - Class 11 |
| Concept | Haldane Effect vs. Bohr Effect |
| Difficulty | 8 |
| Cognitive Load | 6 |
| Target Solve Time | 140 sec |
| Access | Free |