Bohr effect: hemoglobin in exercising muscle
During intense exercise, muscle tissue becomes more acidic and its CO2 level rises. How does this affect hemoglobin there?
Answer B: explanation for every choice
A
A left shift is caused by lower CO2, H⁺, temperature, or 2,3-BPG, or by fetal hemoglobin or carbon monoxide.
B
Correct. H⁺ and CO2 stabilize the low-affinity T state, so hemoglobin unloads more O2 where it is needed.
C
The Bohr effect is a real, physiologically important change in affinity.
D
Binding remains cooperative. The whole curve shifts.
TakeawayIncreased CO2, H⁺, temperature, or 2,3-BPG → right shift → more O2 unloading.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb28.