Mini test Haemoglobin dissociation curves

Question 1

Describe the role of haemoglobin in carrying oxygen

Answer 1

• Haemoglobin made from 4 polypeptide chains
• each chain contains a haem group
• each haem group can carry an oxygen molecule
• Haemoglobin forms with oxygen to form Oxyhaemoglobin

Question 2

Describe the role of haemoglobin in carrying Co2

Answer 2

• Co2 diffuses into RBC
• Carbon dioxide reacts with water to form carbonic acid
• This^ is Catalysed by carbonic anhydrase
• carbonic acid dissociates to form hydrogen ions and hydrogen carbonate ions
• The hydrogen carbonate ions diffuse out of the RBC and carried in the plasma

Question 3

Explain why the feotal haemoglobin curve is to the left of the adult dissociation curve

Answer 3

• Feotal haemoglobin has a higher affinity for oxygen

- Foetal Hb will absorb more oxygen than adult Hb at the same PO2

Question 4

explain how feotal hb can absorb oxygen from adult haemoglobin

Answer 4

• when mother’s blood has reached placenta, it’s saturation level has decreased
• the foetal Hb can absorb oxygen from adult Hb
• as it has a higher affinity for oxygen

Question 5

-State what happens to the haemoglobin dissociation curve as the concentration of C02 increases, name this effect

Answer 5

• it shifts to the right

- The Bohr effect

Question 6

Explain why this shift in the haemoglobin dissociation curve is important (Bohr)

Answer 6

• if there is a high conc. of Co2 there is a high rate of respiration
• More carbonic acid is formed inside the RBC
• More hydrogen ions are formed when the carbonic acid dissociates
• The hydrogen ions cause the OXYHAEMOGLOBIN to dissociate
• Therefore more oxygen is released to the respiring tissue