Haemoglobin

• Structure of Haemoglobin


  Large protein with a quaternary structure

  Each chain has a haem group which contains an iron ion giving it a red colour

  High affinity for oxygen - Each molecule can carry four oxygen molecules

  Haemoglobin + oxygen = oxyhaemoglobin
• The greater the concentration of dissolved oxygen in cells, higher partial pressure
• Oxyhemoglobin unloads when there is a lower partial pressure of oxygen
• Alveoli have a high partial pressure of oxygen so the oxygen loads onto it
• When cells respire they decrease the partial pressure of oxygen
• Dissociation curve graph explanation

  pO2 is high haemoglobin has a high affinity for oxygen, is has a high saturation

  pO2 low haemoglobin has a low affinity for oxygen, so has a low saturation