Haemoglobin

• Biconcave shape that provides a large surface area for absorption of oxygen

  no nucleus or organelles to make room for many haemoglobin molecules in the cytoplasm

  quaternary structure
• to be efficient at transporting oxygen, haemoglobin must…

  • readily associate with oxygen at gas exchange surfaces
  • readily dissociate from oxygen at respiring tissues

  It can do both of these things because it changes its affinity depending for oxygen under different condition

  When in presence of carbon dioxide the affinity will be lower and this reduces the pH and affects the shape of haemoglobin

  need to release oxygen where there is carbon dioxide as this is where respiration is occurring