(a(i))[3]
Explain how the structure of a haemoglobin molecule enables efficient oxygen transport.
(a(ii))[2]
Explain how the structure of a haemoglobin molecule makes it soluble in water.
(b(i))[1]
Llamas are mammals adapted to life at high altitude. Fig. 6.1 shows oxygen dissociation curves for haemoglobin from llamas and humans. At $3500\,\text{m}$, the partial pressure of oxygen in the lungs of mammals is $6.4\,\text{kPa}$. Use Fig. 6.1 to state the percentage saturation of haemoglobin in llamas and humans at an oxygen partial pressure of $6.4\,\text{kPa}$.
(b(ii))[2]
With reference to Fig. 6.1, explain the benefit to llamas of having an oxygen dissociation curve shifted to the left of the human curve.