7.1 Haemoglobin Flashcards
What carries oxygen in red blood cells?
Haemoglobin
How many haem groups does haemoglobin have?
4
Where does oxygen bind to haemoglobin in the lungs?
Iron in haem groups
What is haemoglobin with bound oxygen called?
Oxyhaemoglobin
How many oxygen molecules can one haemoglobin molecule carry?
4
Where does oxyhaemoglobin transport oxygen?
Respiring body tissues (aerobic)
What happens to oxygen at body cells?
Unloads from haemoglobin
What does haemoglobin saturation depend on?
Oxygen concentration or partial pressure of oxygen (pO2)
What are the units of partial pressure of oxygen?
Kilopascals (kPa)
What happens to haemoglobin at higher pO2?
High affinity for oxygen and binds with it (loading)
What happens to haemoglobin at lower pO2?
Low affinity for oxygen and releases it (unloading)
What is the cooperative nature of oxygen binding?
When haemoglobin binds one oxygen it changes the tertiary structure to bind another easier
What happens when haemoglobin is mostly saturated?
Harder for more oxygen to bind
What type of haemoglobin is found in an unborn fetus?
Fetal haemoglobin
Why does fetal haemoglobin differ from adult haemoglobin?
Fetus needs to obtain oxygen from mother’s blood
What oxygen affinity does fetal haemoglobin have compared to adult haemoglobin?
Higher
What does the higher affinity of fetal haemoglobin allow?
Oxygen to unload from mother’s haemoglobin and bind with fetal haemoglobin
What happens to haemoglobin’s oxygen affinity at higher pCO2?
Lower
What causes haemoglobin to release oxygen at respiring tissues?
Higher pCO2/Lower pO2
What is the decreased affinity for oxygen in haemoglobin when carbon dioxide is present called?
Bohr effect
What happens to oxygen saturation of haemoglobin when pCO2 is higher?
Lower for a given pO2
Why is the Bohr effect needed?
Active tissues producing carbon dioxide require a lot of oxygen (need oxygen to unload)
What does the Bohr effect do to the oxygen dissociation curve?
Shifts it to the right
