If the partial pressure of oxygen (pO2) in a man's blood plasma decreased below that in his red blood cells (RBCs), what would be the result?
a. Oxygen would diffuse out of his red blood cells, and less oxygen would be transported throughout his body.
b. More oxygen would diffuse into his red blood cells and be transported throughout his body.
c. The concentration of oxygen would be the same in red blood cells and blood plasma.

A.

Explanation:

Hemoglobin does not have an extremely tight hold on oxygen.  Thus, when the partial pressure around hemoglobin drops, such as in the plasma, oxygen will attempt to reach equilibrium by escaping the hemoglobin, which is on the red blood cells, and entering the plasma.  However, the plasma cannot transport oxygen as well as red blood cells.

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partially rotating elbow joints

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