1. The variety of life continued 3.2.4

4. Why might this be?

6. What causes these different affinities? Different shaped caused by differences in the amino acid sequence.

7. Haemoglobin combining with oxygen is called loading or associating and in humans happens in the lungs.

8. Haemoglobin releasing oxygen is called unloading or dissociating and in humans happens in the tissues.

9. Oxygen dissociation curves.

12. A very small decrease in the partial pressure of oxygen leads to a lot of oxygen becoming dissociated from the haemoglobin

13. Why does the graph tail off at very high concentrations? The haemoglobin is almost saturated .

14. As there are many different types of haemoglobin and respond to different conditions many oxygen dissociation curves exist but they all have the same basic shape.

19. Dissolved carbon dioxide is acidic and this low ph is what causes the haemoglobin to change shape.

21. This is useful as it makes sure each tissue gets the right amount of oxygen. More active tissue produces more carbon dioxide and needs more oxygen.

22. Other organisms

25. Answer green question 1-6 on page 155

27. Because of this the curve is shifted to the right.