Haemoglobin

• What is haemoglobin?

  A group of proteins found in different organisms that are responsible for the transport of oxygen around the body.
• What type of structure does haemoglobin have?

  Quaternary structure
• What is the affinity of haemoglobin for oxygen?

  The ability of haemoglobin to bind to oxygen.
• What is the saturation of haemoglobin with oxygen?

  When haemoglobin is holding the maximum amount of oxygen it can bind to.
• What is the association of oxygen with haemoglobin?

  The binding of oxygen to haemoglobin.
• What is the dissociation of oxygen from haemoglobin?

  When oxygen unbinds from haemoglobin.
• Where is oxygen loaded?

  In regions of high partial pressure of oxygen, such as the alveoli.
• Where is oxygen unloaded?

  In regions with a low partial pressure of oxygen, such as respiring tissues.
• Oxyhaemoglobin Dissociation Curve

  A) Percentage saturation of haemoglobin with oxygen (%)

  B) Partial pressure of oxygen (kPa)

  
• Explain the cooperative binding ox oxygen molecules.

  Haemoglobin changes shape when the first oxygen molecule binds. This makes it easier for further oxygen molecules to bind.
• What is the Bohr effect?

  • A high carbon dioxide concentration causes the oxyhaemoglobin curve to shift to the right.
  • The affinity for oxygen is decreased because acidic carbon dioxide changes the shape of haemoglobin slightly.
• What happens to haemoglobin in the alveoli?

  • There is a low partial pressure of carbon dioxide.
  • The curve shifts to the left.
  • Affinity for oxygen is increased.
  • Haemoglobin associates with oxygen more easily.
• What happens to haemoglobin at respiring tissues?

  • There is a high partial pressure of carbon dioxide.
  • The curve shifts right.
  • Decreased affinity for oxygen.
  • Haemoglobin dissociates from oxygen more easily.
• Why do animals have different types of haemoglobin?

  Different haemoglobins have different affinities for oxygen. This allows animals to adapt to their environments.
• Explain the difference of foetal haemoglobin.

  • The curve is shifted to the left.
  • At the same partial pressure of oxygen, foetal haemoglobin has a higher affinity for oxygen so is more saturated.
  • This is important because foetuses receive oxygen from the mother's blood, so must have a higher affinity in order to access this oxygen.
• Explain llamas' haemoglobin.

  • Llamas live at high altitudes where there is a lower partial pressure of oxygen.
  • The curve is shifted to the left.
  • Their haemoglobin has a higher affinity for oxygen.
• Explain doves' haemoglobin.

  • The curve is shifted to the right; their haemoglobin has a lower affinity for oxygen.
  • Doves have a faster metabolism so need more oxygen for respiration, to produce energy for contracting muscles.
• Explain earthworms' haemoglobin.

  • Earthworms live underground where there is a lower partial pressure of oxygen.
  • The curve is shifted to the left: their haemoglobin has a higher affinity for oxygen.