HideShow resource information

<!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } -->

Haemoglobin (Hb) is the PROTEIN that carries oxygen around the body - it is a large protein, it has a quaternary structure and is made up of 4 polypeptide chains

  • each of these polypeptide chains has a HAEM group. This contains IRON which gives haemoglobin its red colour

  • It varies from species to species, depending on their habitat

  • Haemoglobin is the pigment found in Red Blood Cells


The above process, of OXYGEN JOINING TO HAEMOGLOBIN occurs in the lungs. This is a reversible reaction as when the oxygen leaves the the oxyhaemoglobin (dissociation in the body cells) it turns back to haemoglobin.

As we can see, the haemoglobin can carry 4 oxygen molecules (4O2) we say that HAEMOGLOBIN HAS A HIGH AFFINITY FOR OXYGEN.

The PARTIAL PRESSURE of oxygen (pO2) is a measure of the OXYGEN CONCENTRATION. ie. The greater the concentration, the higher the partial pressure.

Red Blood Cells PICK UP OXYGEN IN THE LUNGS, here the partial pressure of oxygen is HIGH. The oxygen becomes SATURATED with the haemoglobin.

Once the oxygen is loaded onto the haemoglobin, forming oxyhaemoglobin, then it is carried by the cells to the RESPIRING TISSUES. The partial pressure of oxygen in the respiring tissues is LOW as it is constantly being used up in respiration.

When the partial pressure is at these conditions, low, then the oxyhaemoglobin GIVES UP its oxygen to these respiring tissues, this is called DISSOCIATION.

The Haemoglobin then returns to the lungs to…


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Biological molecules, organic chemistry and biochemistry resources »