Question

Carbon dioxide dissociates from carbaminohaemoglobin when

• A. Partial pressure of carbon dioxide is high and partial pressure of oxygen is low.
• B. Partial pressure of carbon dioxide is low and partial pressure of oxygen is high.
• C. Partial pressures of both oxygen and carbon dioxide are equal.
• D. None of the above.

Answer 1

The correct option is B

Partial pressure of carbon dioxide is low and partial pressure of oxygen is high.

When partial pressure of carbon dioxide is high and that of oxygen is low as in the tissues, more binding of carbon dioxide occurs, whereas, when the partial pressure of carbon dioxide is low and that of oxygen is high, as in the alveoli, dissociation of carbon dioxide from carbaminohaemoglobin takes place, i.e., carbon dioxide which is bound to haemoglobin from the tissues is delivered at the alveoli.