Multiple Choice Questions About Respiratory System Related

Review Multiple Choice Questions About Respiratory System related questions and content

When CO2 diffuses into blood in systemic capillaries most of it:

  • A. Remains in solution as CO2
  • B. Converts to carbamino compounds
  • C. Converts to bicarbonate ions in RBC
  • D. Combines with Hb directly
Correct Answer: C

Rationale: The correct answer is C because the majority of CO2 diffusing into blood combines with water inside red blood cells (RBC) to form carbonic acid, which then dissociates into bicarbonate ions and hydrogen ions. This reaction is facilitated by the enzyme carbonic anhydrase. This process allows for efficient transport of CO2 in the bloodstream. Choices A and B are incorrect as CO2 primarily undergoes conversion to bicarbonate ions, not remaining in solution as CO2 or forming carbamino compounds. Option D is incorrect as CO2 does not directly combine with hemoglobin.