haemoglobin

• How many litres of blood in an adult human?

  5
• How many red blood cells per microliter of blood?

  5 million
• How many molecules of haemoglobin per red blood cell?

  270 million molecules
• label the diagram

  A) primary structure

  B) secondary structure

  C) tertiary structure

  D) quaternary structure

  
• How O2 is transported in humans

  haemoglobin
• How O2 is transported in spiders, crustaceans, etc.

  haemocyanin
• How O2 is transported in worms, leeches

  chlorocruorin
• How O2 is transported in marine worms

  haemorythrin
• Haemoglobin and oxygen affinity

  • Four O2 molecules can bind to each haemoglobin molecule
  • 4O2 + Hb (deoxyhaemoglobin) ⇄ HbO8 (oxyhamoglobin)
  • Haemoglobin has a high affinity for oxygen
• Dissociation curves

  • The shape of haemoglobin changes as oxygen molecules associate with it
  • An oxygen dissociation curve visually represents the relationship between the partial pressure of oxygen in the blood (pO2) and the saturation of haemoglobin with oxygen, essentially showing how much oxygen is bound to haemoglobin at different oxygen levels
• Partial pressure

  • The concentration of oxygen in the body is referred tocas its partial pressure for oxygen (pO2); measured in kPa
  • Haemoglobin has a higher affinity for oxygen where the pO2 is high,
  • There is a high pO2 in the lungs
  • So more oxygen associates with haemoglobin
  • The pO2 is low in respiring tissues
  • Oxygen dissociates from haemoglobin and diffuses to the respiring cells
• effect of carbon dioxide

  CO2 can bind to haemoglobin and change the shape of the molecule so it has a lower affinity for oxygen
• effect of carbond dioxide

  • In respiring tissue:
  • More CO2 produced
  • Hb has lower affinity for oxygen
  • More oxygen dissociation
  • In the lungs:
  • Less CO2 present
  • Hb has higher affinity for oxygen
  • More oxygen binding