- A CO reacts with plasma proteins to form toxic precipitates in typical laboratory settings
- B CO destroys red blood cells within minutes of exposure as generally observed
- C CO drives an excessive rise in red blood cell production under usual circumstances
- D CO binds hemoglobin far more strongly than oxygen, blocking O2 sites
Correct answer: D. CO binds hemoglobin far more strongly than oxygen, blocking O2 sites
Explanation: Carbon monoxide binds hemoglobin with about 200 times greater affinity than oxygen, forming stable carboxyhemoglobin and effectively blocking the sites needed for oxygen transport.
Concept context
The mechanics of breathing, lung volumes, gas transport in blood, the Bohr effect, and respiratory regulation.