Answer: A rise in blood pH, since less carbonic acid is formed.
- A A rise in blood pH, since less carbonic acid is formed
- B Increased binding of CO<sub>2</sub> to haemoglobin as carbaminohaemoglobin
- C No change in pH, since CO<sub>2</sub> does not affect blood acidity
- D A fall in blood pH, due to excess bicarbonate accumulation
Correct answer: A. A rise in blood pH, since less carbonic acid is formed
Explanation: Excessive removal of CO<sub>2</sub> during hyperventilation reduces carbonic acid formation in blood, raising blood pH (respiratory alkalosis).
The S-shaped (sigmoid) curve reflects cooperative binding between Hb's four O₂ sites; the Bohr effect shifts the whole curve to the right under conditions found in actively respiring tissue (more CO₂, more acid, more heat), making haemoglobin release oxygen more readily exactly where it's needed.
Concept context
The mechanics of breathing, lung volumes, gas transport in blood, the Bohr effect, and respiratory regulation.