Question

Questions about pH

a) What is the pH of blood in the tissue and in the lungs?

b) Why does that difference in pH help hemoglobin do its job of delivering oxygen?

Answer 1

Ans a) The pH near the lungs is high or it increases due to the decrease in the concentration of the carbon dioxide and hence the pH near the lungs. Since the lungs is responsible for elimination of C02, the blood pH tends to be on alkaline side and is majorly higher than 7.45. Normally in the normal condition the blood pH is neutral but when it comes to tissues, the pH tends to be acidic as the tissues have the tendency to absorb C02 and it leads to increase formation of carbonic acid.

Ans 2) The pH difference in blood helps hemoglobin to deliver oxygen and this is due to the Bohr Effect. With the rise in the pH, the hemoglobin tends to lose hydrogen ions and hence there is some conformational changes that take place. With the change in the conformation, it increases the ability of the hemoglobin to bind more oxygen and hence it is able to deliver more oxygen. However, when the pH falls, the hemoglobin’s affinity towards oxygen decrease as its affinity towards hydrogen ion increases.