Haemaglobin

• How is foetal haemoglobin adapted to increase aerobic respiration and prevent anaerobic respiration?

  It has a high affinity for O2 meaning it can obtain oxygen via the placenta allowing aerobic respiration and preventing anaerobic respiration causing a shift to the left.
• How is myoglobin adapted to increase aerobic respiration and prevent anaerobic respiration?

  Myoglobin is a store of oxygen so it only dissociates from O2 in very low PO2s therefore it maintains aerobic respiration and prevents anaerobic respiration causing a shift to the left.
• How do small mammals adapt to survive?

  They have a relatively large surface area to volume ratio so loose thermal energy quickly meaning they have to aerobically respire at a higher rate meaning the haemoglobin dissociates with O2 more often causing a Bohr shift.
• How do animals with high activity levels adapt to survive?

  Their tissues require plenty of oxygen to maintain aerobic respiration so Haemoglobin has to be able to easily dissociate. This causes the Bohr shift which is an advantage as the small decrease of PO2 will cause a large dissociation of O2 therefore can maintain a high rate of aerobic respiration and prevent anaerobic respiration.
• How do organisms adapt to environments with low oxygen?

  Haemoglobin has to be good at loading oxygen in lower PO2s (the curve would move to the left). The advantage of this position is that haemoglobin is fully saturated even in lower PO2s therefore allowing aerobic respiration and preventing anaerobic respiration.
• Model answer for all 3 graphs

  By creating a lower Hb % saturation of O2 there will be a lower affinity between Hb and O2 so it is more likely to dissociate to maintain aerobic respiration and prevent anaerobic respiration
• What is the effect of Pco2 increasing on the % saturation of Hb?

  The Bohr shift would occur
• What is the effect of increasing temperature on the % saturation of Hb?

  The Bohr shift would occur
• What is the effect of decreasing PH on the % saturation of Hb?

  The Bohr shift would occur
• What is a Bhor shift?

  where a graph moves to the right
• What happens when the 4O2 leaves the red blood cell?

  It releases oxygen as it dissociates from haemoglobin where it moves into respiring cells as there is a lower PO2 for aerobic respiration to occur and to prevent anaerobic respiration.
• What happens to the H(plus) ion in the red blood cell?

  Oxyhemoglobin's Hb binds to the H to create HHb and the O2 leaves the red blood cell via diffusion.
• What happens to the carbonic acid in the red blood cell?

  It diffuses out of the cell into the plasma
• What is HCO3(minus)?

  Carbonic acid
• What happens to the CO2 in the red blood cell?

  It undergoes chemical reactions to produce H(plus) + carbonic acid (which lowers the PH).
• By what method of transport does CO2 in plasma move into the red blood cell?

  Simple diffusion
• What waste product of aerobic respiration moves into the red blood cell during loading of CO2?

  CO2 in plasma
• Section C model answer of the haemoglobin sigmoid curve

  When PO2 starts to increase from very low PO2 the first O2 that associates with haemoglobin causes a change in the quaternary structure. This exposes all 3 haem groups making it easier for O2 to associate. This leads to rapid increase in percentage saturation.
• Explain the Haemoglobin writing frame

  1. What is happening to the PO2 - (There is a high PO2 in the lungs)2. How is there affinity to O2 - (therefore haemoglobin has a high affinity for O2)3.Does O2 associate or dissociate - (therefore haemoglobin is more likely to associate with O2)4.Finish the scenario - (allowing haemoglobin to become fully saturated with O2)
• What is the symbol for partial pressure of oxygen?

  PO2
• What does the % saturation of haemoglobin mean?

  How many of the Hb are fully saturated/ have turned into HbO8
• What do you call an s shaped curve?

  Sigmoidal curve
• Define affinity


  How likely something is to occur
• Haemoglobin is a protein containing what haem group?

  fe2+
• What is the symbol for oxyhemoglobin?

  HbO8
• What is the symbol for haemoglobin?

  Hb
• What is haemoglobin + oxygen

  Oxyhemoglobin
• How does having a biconcave shape help red blood cells to carry out their function?

  It gives them a large surface area which increases the rate of diffusion of O2
• How does having 250 million molecules of haemoglobin per red blood cell help them to carry out their function?

  More haemoglobin can associate with the O2
• Why does having no nucleus help red blood cells to carry out their function?

  There is more space to load oxygen.
• How does a 2 phospholipid thick membrane help the red blood cell to carry out its function?

  It creates a short diffusion pathway allowing oxygen to diffuse straight into the cell.
• What are the functions of red blood cells?

  To carry oxygen from the lungs to respiring tissues.
• What 4 adaptations do red blood cells have?

  2 phospholipid thick membrane, no nucleus, 250 million molecules of haemoglobin per red blood cell, biconcave shape.