- A Dissolved CO2 in plasma, accounting for the majority of transported gas
- B Carbaminohemoglobin formed by binding to globin chains exclusively
- C Bicarbonate ions (HCO3-) in plasma (~70%)
- D Carbonic acid accumulating freely in plasma without further dissociation
Correct answer: C. Bicarbonate ions (HCO3-) in plasma (~70%)
Explanation: About 70% of CO2 is transported as bicarbonate (HCO3-) in plasma. About 20% bound to Hb (as carbaminoHb). 10% dissolved.
Concept context
The mechanics of breathing, lung volumes, gas transport in blood, the Bohr effect, and respiratory regulation.