Haemoglobin
1 haemoglobin can carry 4 oxygen molecules. Oxygen combines with haemoglobin to form oxyhaemoglobin
Haemoglobin's affinity
If Hb combines easily with oxygen, we say that it has a high affinity for oxygen. Hb has a higher affinity where there is a higher concentration or partial pressure of oxygen
Confromational shape
As each oxygen molecule binds to haemoglobin, it causes a shape change in the protein meaning that it is easier to bind the next oxygen molecule
Place where oxygen for the foetus comes from
Foetus gains its oxygen from its mother's blood across the placenta
How is foetal haemoglobin adapted to load up easily with oxygen
Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin, so a foetus can absorb oxygen from the mother's blood at all.
Foetal Hb
Has a greater affinity for oxygen, its oxygen dissociation curve is shifted to the left of the mother's curve, mother's Hb releases oxygen and the foetal Hb combines with this oxygen.
Curve to the left
Hb is better at loading oxygen
Curve to the right
Hb is better at releasing oxygen
Myoglobin
Pigment which binds to oxygen, only found in muscle cells and is an oxygen store with a high affinity for oxygen even at low partial pressures.