Oxygen Dissociation Curves
When haemoglobin is exposed to different partial pressure of O = doesn't absorb oxygen evenly.
Low concs of O = 4 polypeptides of haemoglobin molecule = closely united = difficult to absorb first oxygen molecule.
Once loaded oxygen molecule causes polypeptides to load remaining 3 O moleculs very easily.
Graph of this relationship = oxygen dissociation curve.
V small decrease in partial pressure of O leads to lots of O becoming dissociated from haemoglobin.
V high concs of oxygen = graph tails off because haemoglobin is almost saturated with oxygen.
Shape of haemoglobin can change under different conditions = large number of different oxygen dissociation curves - roughly similar shape but position on axes differs:
- Further to the left the curve is = greater affinity of haemoglobin for oxygen (takes up more easily).
- Further to the right = lower affinity of haemoglobin for oxygen…