Transport of oxygen in haemoglobin

• What do dissociation curves represent?

  Illustrates change in haemoglobin saturation as partial pressure changed.
• How is saturation of haemoglobin affected by its oxygen affinity?

  If partial pressure is high, oxygen affinity is high, meaning haemoglobin is highly saturated
• How does saturation affect oxygen affinity?

  After binding to first oxygen molecule, oxygen affinity for haemoglobin increases due to changed shaped so easier to bind
• Why does fetal haemoglobin have a different affinity to adult haemoglobin?

  As it needs to be better at absorbing oxygen as by the time oxygen reaches the placenta, oxygen saturation of blood decreases so must have a higher affinity for foetus to survive low partial pressure
• How is oxygen affinity of haemoglobin affected by partial pressure of carbon dioxide?

  presence of carbon dioxide, oxygen affinity decreases causing O2 to be released = Bohr effect
• How does carbon dioxide create a lower affinity?

  Creates slightly acidic conditions and changes shape of the haemoglobin protein so oxygen easier to be released