Physiology & Biochemistry · single question
How is the majority of CO2 transported from tissues back to the lungs in blood?
Show answer and explanation
Correct answer: C. As bicarbonate (via carbonic anhydrase)
- A. Incorrect – CO is a toxic gas, not a CO2 transport form.
- B. Incorrect – only ~7–10% travels dissolved.
- C. Correct – ~70% of CO2 is carried as HCO3− after carbonic anhydrase in RBCs converts CO2 + H2O → H2CO3 → HCO3−.
- D. Incorrect – carbaminohemoglobin carries ~20–23%, not the majority.
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