HAEMOGLOBIN
● haemoglobin is a water-soluble globular protein
● it has two alpha and two beta polypeptide chains, each with a
prosthetic haem group
● oxygen binds to the haem group which contains Fe2+ and each
haemoglobin molecule can carry 4 oxygen molecules
BINDING OF OXYGEN
● Affinity= chemical attraction
● Affinity of oxygen for haemoglobin depends on partial pressure of
oxygen- A measure of oxygen concentration, based on the
contribution of oxygen to the total pressure of a mixture
● As the partial pressure of oxygen increases, affinity increases so
oxygen binds tightly eg. in the lungs, oxygen binds by a process
called loading
● when the partial pressure of oxygen decreases at respiring tissues,
affinity decreases so oxygen is released/ unloaded
DISSOCIATION CURVES
Dissociation curves illustrate the change in haemoglobin saturation as the
partial pressure of oxygen changes. When the partial pressure of oxygen is
high, affinity is high and therefore saturation is high.
● haemoglobin is a water-soluble globular protein
● it has two alpha and two beta polypeptide chains, each with a
prosthetic haem group
● oxygen binds to the haem group which contains Fe2+ and each
haemoglobin molecule can carry 4 oxygen molecules
BINDING OF OXYGEN
● Affinity= chemical attraction
● Affinity of oxygen for haemoglobin depends on partial pressure of
oxygen- A measure of oxygen concentration, based on the
contribution of oxygen to the total pressure of a mixture
● As the partial pressure of oxygen increases, affinity increases so
oxygen binds tightly eg. in the lungs, oxygen binds by a process
called loading
● when the partial pressure of oxygen decreases at respiring tissues,
affinity decreases so oxygen is released/ unloaded
DISSOCIATION CURVES
Dissociation curves illustrate the change in haemoglobin saturation as the
partial pressure of oxygen changes. When the partial pressure of oxygen is
high, affinity is high and therefore saturation is high.
