CAIE A Level Biology 9700 · Transport in mammals
The table below shows the partial pressure of oxygen (PO₂) and the corresponding percentage saturation of haemoglobin at two locations in the human body.
| Location | PO₂ / kPa | Percentage saturation of haemoglobin |
|---|---|---|
| Alveoli | 13 | 97 |
| Respiring tissues | 5 | 60 |
Describe the significance of the oxygen dissociation curve and the Bohr shift in ensuring efficient 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.
Written by Markquill to follow the Cambridge International syllabus. Markquill is independent and is not affiliated with or endorsed by Cambridge International.