Bohr Effect on Hemoglobin-Oxygen Affinity

Steps:

• Hemoglobin's ability to bind and release oxygen depends on CO2 levels through the Bohr effect.
• Increasing PCO2 lowers blood pH, reducing hemoglobin's oxygen affinity and shifting the dissociation curve right for easier release in tissues.
• Decreasing PCO2 raises pH, increasing affinity and shifting the curve left.
• Left shift promotes oxygen binding at lung PO2 levels but hinders unloading at tissue PO2 levels.

Why B is correct:

• Decreasing PCO2 boosts hemoglobin's oxygen affinity (left curve shift), enhancing uptake in lungs while impairing release in tissues, per the Bohr effect definition.

Why the others are wrong:

• A: Decreasing PCO2 increases, not decreases, efficiency for both uptake and release.
• C: It improves uptake but reduces, not improves, release efficiency.
• D: It enhances uptake, not reduces it, while impairing release.

Final answer: B