[aj3537]

Crocodile hemoglobin responds more strongly than human hemoglobin to carbon dioxide, which allows them to stay under water longer. Sketch a curve of percent saturation of hemoglobin versus oxygen pressure for human hemoglobin vs. human hemoglobin + carbon dioxide vs. crocodile hemoglobin + carbon dioxide.

A typical hemoglobin/myoglobin graph has the y axis as percent saturation and the x axis as the oxygen pressure.

If I changed the x axis to carbon dioxide pressure, wouldn't hemoglobin bind to carbon dioxide in the exact same curve as the typical graph? As the carbon dioxide pressure increases, percent saturation of hemoglobin also increases?

If this is the case, I can draw the typical hemoglobin/myoglobin graph and relabel the myoglobin line,  Crocodile hemoglobin, since it has the same higher affinity for carbon dioxide as myoglobin has for oxygen.

[Yggdrasil]

Perhaps the question is referencing the Bohr effect:

http://en.wikipedia.org/wiki/Bohr_effect