Haemoglobin

• haemoglobin

  is a protein. Has 4 polypeptides, each associated with a haem group. Each can carry an oxygen molecule
• role of haemoglobin

  1.Haemoglobin carries oxygen as it has a high affinity for oxygen and forms oxyhaemoglobin

  2. In red blood cells

  3. Loading happens in lungs

  4. at high partial pressure of oxygen

  5. dissociates to respiring tissues

  6. at low partial pressure of oxygen

  7. Unloading at higher carbon dioxide concentration
• reason for s shaped dissociation curve

  First oxygen binds to haemoglobin causing it to change shape

  Shape change allows more oxygen to bind easier
• oxygen dissociated curve shifted to right


  usually smaller animals with large surface area to volume ratio that lose heat rapidly as respiration is faster

  Haemoglobin has a lower affinity for oxygen

  so dissociates to respiring tissues and becomes

  saturated more readily at higher partial

  pressure of oxygen

  more oxygen to cells for more respiration to generate heat

  would benefit human if it shifted to the right during exercise
• oxygen dissociation curve shifted to left


  animals in environments with less oxygen

  Haemoglobin has a higher affinity for oxygen

  Haemoglobin becomes saturated and dissociates to respiring tissues more readily at lower partial pressure of oxygen
• more respiration means…

  more CO2 so lower pH so reduces affinity for oxygen by changing shape of haemoglobin so shifts curve to right, Bohr effect
• bohr effect is advantageous during excersise


  increases the dissociation of oxygen

  -for aerobic respiration at cells

  -Anaerobic respiration delayed at cells, so less lactate
• people with more red blood cells…


  have more haemoglobin so can load more oxygen

  usually live in places with not very much oxygen