Answer:
enhances O2 release in respiring tissues
Explanation:
Two factors determine the binding of oxygen with haemoglobin(Hb) in the lungs;
the high partial pressure of oxygen in the lungs , low partial pressure at the respiring tissues
and
the high partial pressure of carbon dioxide in the blood
Hb binds with oxygen in the lungs and transports this in the blood to the cells. In the respiring cells C02 diffuses from the respired cells to the blood plasma.It combines with the plasma to form cabonic acid (H2C03), This reversible reaction is catalysed by the enzyme carbonic anhydrase.
C02 + H20 ⇄ H2C03.
carbonic anhydrase,
the H2C03, breaks down to hydrogen ion and hydrogen carbonate ion in the blood .
H2C03 ⇄ H+ + H2C03-
The above reaction produces two effects;
1.The hydrgen ion lowers the blood pH,and increases its acidity. Hb mops up the hydrogen ions by combining with it to form haemoglobinic acid(HHb). Thus acting as buffers to lower the blood pH.
2.Most importantly the high partial pressure of C02 in the blood made Hb to release its oxygen molecules to the blood to reach the tissues(Bohr effect) while the hydrogen ion it bonded with in HHb, combines with hydrogen carbonate ion in the blood , to be transported in the blood to the lungs.
H + HC03- ⇄ H2C03 the carbonic acid breaks down to release C02 in the lungs.
Therefore the high partial pressure of C02 in the blood enabled the release of Oxygen by haemoglobin to the respiring tissues from the blood. This is Borh effect, discovered by Christain Borh in 1904.
A dissociation curve will show high bonding of Hb with oxygen at high partial pressure of C02 with Hb, making the curve to move far right of the normal curve.
