Oxygen dissociation

• What is the structure of haemoglobin?

  • Quaternary structure, globular protein
• Can you explain the oxyhaemoglobin dissociation curve?

  • Oxygen is loaded in an area of high partial pressure of oxygen (alevoli)
  • Oxygen is unloaded in an area of low partial pressure of oxygen (respiring tissues)
• What is cooperative binding?

  • The first oxygen is difficult to bind
  • Once the first oxygen binds it changes the structure of the haemoglobin so oxygen is easier to bind
• What is the bohr effect?

  • When a high concentration of carbon dioxide causes the oxyhaemoglobin curve to shift to the right
  • This is because carbon dioxide turns into carbonic acid which changes the shape of the haemoglobin, this makes it easier to unload oxygen
  • The affinity for oxygen decreases as the acidic CO2 changes the shape of the haemoglobin
• What is oxygen affinity

  • How easy it is for an organism to load oxygen onto its haemoglobin
• Can you explain the foetal oxyhaemoglobin curve?

  • Fetuses have a higher affinity for oxygen at the same partial pressure
• Can you explain the llama oxygaemoglobin curve?

  • Because llamas live at high altitudes with low partial pressures of oxygen, they have a higher affinity for oxygen
• Can you explain the oxyhaemoglobin curve of a bird?

  • Because birds have a higher metabolism they need to unloaded oxygen easier for respiration
  • Because of this they have a lower affinity for oxygen at the same parital pressure
• Can you explain the oxyhaemoglobin curve of a worm?

  • Underground there is a lower partial pressure of oxygen
  • Because of their they have a higher affinity for oxygen to more readily load the oxygen