Q. Bicarbonate ions are generated in
NTA AbhyasNTA Abhyas 2020
Solution:
70% of all CO2 is transported through production of HCO3– ions in the red blood cell. CO2 diffuses into the red blood cells and is converted to H+ and HCO3– by an enzyme called carbonic anhydrase. This enzyme is typically found in the RBCs. This HCO3– is transported back into the blood via a chloride-bicarbonate exchanger. This movement of chloride ions is called Chloride shift or Hamburger phenomenon. The bicarbonate can now act as a buffer against any hydrogen in the blood plasma.
The protons created by the carbonic anhydrase reaction in the red blood cell binds to haemoglobin to produce deoxyhaemoglobin. This contributes to the Bohr effect as O2 released from haemoglobin is promoted in active tissues where H+ concentration is higher. It also prevents hydrogen entering the blood to lower pH, stabilising the pH.
When the red blood cells reach the lungs, oxygen binds to the haemoglobin and promotes the R state, allowing the release of H+ ions. These hydrogen ions become free to react with bicarbonate ions to produce CO2 and H2O, where the CO2 is exhaled. Thus, the high O2 concentration reduces the CO2-carrying capacity of blood, in accordance with the Haldane effect.
The protons created by the carbonic anhydrase reaction in the red blood cell binds to haemoglobin to produce deoxyhaemoglobin. This contributes to the Bohr effect as O2 released from haemoglobin is promoted in active tissues where H+ concentration is higher. It also prevents hydrogen entering the blood to lower pH, stabilising the pH.
When the red blood cells reach the lungs, oxygen binds to the haemoglobin and promotes the R state, allowing the release of H+ ions. These hydrogen ions become free to react with bicarbonate ions to produce CO2 and H2O, where the CO2 is exhaled. Thus, the high O2 concentration reduces the CO2-carrying capacity of blood, in accordance with the Haldane effect.