haemoglobin Flashcards
where is haemoglobin found
Red blood cells(erythrocytes)
structure of haemoglobin
It is a quaternary structured protein as it is made of 4 polypeptide chains . Each polypeptide chain contains a haem group containing iron ion which combines to oxygen.
How does haemoglobin load and unload oxygen
Haemoglobin can carry 4 oxygen molecules one at each haem group. In the lungs , at a high partial pressure haemoglobin has a high affinity for oxygen and as a result it readily associates with haemoglobin. At respiring tissues at a low partial pressure oxygen dissociates from haemoglobin. When haemoglobin is unloaded it diffuses into the respiring cell down the concentration gradient as these cells have less concentration of oxygen.
Bohr effect
As concentration of CO2 is high the rate of unloading is faster. This is advantageous as it provides more oxygen for respiring tissue that are undergoing aerobic respiration
Importance of diffusion
Oxygen diffuses from the haemoglobin into respiring tissue and this diffusion of oxygen is crucial for cells to carry out their functions. For example the coronary arteries transport oxygen to cardiac muscle as energy from oxidative phosphorylation to form ATP releases energy for the cardiac muscle to continually contract and relax. This allows blood to flow to other respiring cells so that oxygen can diffuse into the cells. Without haemoglobin the red blood cells wouldn’t be able to transport blood properly and this means oxygen from blood would not be able to diffuse to different cells that require oxygen.
