CAIE A Level Biology 9700 · Transport in mammals
A student measured the partial pressures of oxygen and carbon dioxide in the lung alveoli and in a respiring muscle. The results are shown in the table.
| Location | / kPa | Haemoglobin saturation / % | / kPa |
|---|---|---|---|
| Lung alveoli | 13 | 98 | 5 |
| Respiring muscle | 4 | 25 | 10 |
Using the data, describe the relationship between oxygen partial pressure and haemoglobin saturation at the two locations. Explain how the Bohr shift aids oxygen delivery to respiring tissues.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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