Haemoglobin molecule is made of four polypeptide chains, each with a haem group attached to it. Haem is a prosthetic group. In the middle of each haem group there is an iron ion, which can be assoiciated with one oxygen molecule. Since haemoglobin has four haem groups, each haemoglobin molecule can carry four oxygen molecules. As the first haem group combines with an oxygen molecule, the shape of the haemoglobin molecule changes slightly. This exposes the next haem, making it easier for it to pick up more oxygen.
Comments
No comments have yet been made