Types of haemoglobin
- Haemoglobin is found in many different animal species.
- Different forms are also found within a species.
- The haem group has the same structure in all.
- The globin components differ.
- This affects the shape of the molecule.
- This affects:
- Their ability to combine with oxygen.
- The conditions in which they take up and release oxygen.
- Organisms who inhabit habitats with low oxygen concentration require haemoglobin that combines readily with oxygen:
- They have an oxygen dissociation curves with a very steep gradient.
- Eg lug worm
- Eg llama
- Organisms with high metabolic rates require haemoglobin that releases oxygen readily:
- Eg mice have a high SA:vol.
- They lose heat easily.
- They need a high metabolic rate.
- Eg birds have a higher metabolic rate due to flight.
- Their oxygen dissociation curve is further to the right.
- They release oxygen more easily at the tissues.
- When it comes to IBDP Biology, the maternal haemoglobin releases its oxygen at the placenta .
- Oxygen concentration is relatively low.
- It diffuses across the placenta into the foetal blood.
- The foetal haemoglobin can pick up oxygen at these low concentrations.
- Curve is displaced to the left of adult curve.
- Foetal haemoglobin has higher affinity for oxygen than adult haemoglobin at any given partial pressure.
- After birth, the baby starts to make normal haemoglobin.
When it comes to IBDP Biology, myoglobin is
- Found in vertebrate muscles, particularly large mammals.
- Only one haem unit.
- Dissociation curve is displaced to the left.
- Myoglobin has greater affinity for oxygen than haemoglobin.
- Enable myoglobin to retain oxygen at low partial pressures.
- Acts as a store of oxygen.
- Oxygen released when at very low concentrations.
- I.E. during exercise.
This is the end of this topic