MHT CET Medical202622 April 2026Evening ShiftBiologyBreathing and Exchange of GasesActual
Given below are two statements about transport of O ₂ and CO ₂ . Statement (I): In the alveoli, where ppO ₂ is high and ppCO ₂ is low, the oxygen binds to haemoglobin. Statement (II): In the alveoli under low ppCO ₂ , hydrogen ion and bicarbonate ions recombine under the influence of the enzyme carbonic anhydrase and release CO ₂ . In light of the above statements, choose the most appropriate answer from the options
Options
- ABoth Statement (I) and Statement (II) are correct.
- BBoth Statement (I) and Statement (II) are incorrect.
- CStatement (I) is correct but Statement (II) is incorrect.
- DStatement (I) is incorrect but Statement (II) is correct.
Correct answer
A. Both Statement (I) and Statement (II) are correct.
Step-by-step solution
Statement (I) is correct. In the alveoli, the partial pressure of oxygen ( pO ₂ ) is high and the partial pressure of carbon dioxide ( pCO ₂ ) is low. Along with lesser H ^+ concentration and lower temperature, these factors are highly favourable for the binding of oxygen with haemoglobin to form oxyhaemoglobin. Statement (II) is correct. At the alveolar site where pCO ₂ is low, the reaction catalyzed by the enzyme carbonic anhydrase proceeds in the reverse direction. Bicarbonate ions ( HCO ₃^- ) and hydrogen ions