Answer:
Oxygen binds with Heme though cooperate binding.This means that as the oxygen molecule binds to the first of the 4 heme groups,it weakened the intermolecular forces, holding the heme group,causing structural change in the Hb molecule.
This increases the affinity of Hb for more oxygen.Therefore facilitating easy binding of the second oxygen atoms.The 3rd will be faster,while the the binding of the 4th Oxygen atom is the fastest.This is cooperative binding.
The oxygen binding to the heme group in the lungs at high partial pressure of oxygen (with low partial pressure of CO2)shifts the dissociation curve for oxygen to the left, so that the heme group hold oxygen molecule tight and transport this to be released in the tissues. The high partial pressure and concentration of CO2 at the tissues enable the unloading of Oxygen.This is called Bohr's effects.Here ( tissues) the curves shifts to the right for Hb to unload O2.
When CO2 dissolve in water in the blood,it dissolves in water in the presence of an enzyme carbonic anhydrase to form H2CO3. This is unstable and dissociate into H+ and HC03-
The H+ increases the acidity of the blood, and the blood capillaries.Thus it increases the acidity of the capillaries.However, this is mopped by Hb to form heamoglobinic acid.(HHB).Thus it acts as a buffer.
With the presence of Oxygen, Hb releases oxygen it was carrying to the cells. Bohr' effects
The HCO3- from above diffuses from the blood into the blood plasma, to be carried in solution to the lungs, to release oxygen.CI- from the plasma diffuses back into the blood to balance the electronegativity.This is chloride shift.
Explanation:
