Question

Which of the following factors raise the $P_{50}$ and shifts the $Hb{O}_2$ dissociation curve to right and vice versa?
a. Rise in $Pc{o}_2$
b. Fall in temperature
c. Rise in $H^{+}$ (=fall in pH)
d. Fall in diphosphoglyceric acid

• A. a and b are correct
• B. b and d are correct
• C. a and c are correct
• D. a, b and c are correct

Answer 1

The correct option is C a and c are correct

The important conditions affecting the oxygen-haemoglobin dissociation curve are the pH, the temperature and the concentration of 2,3 diphosphoglycerate.
i. A rise in temperature or fall in pH shifts the curve to the right. When the curve is shifted in this direction, a higher $P{O}_2$ is required for haemoglobin to bind a given amount of oxygen.
ii. A fall in temperature or rise in pH shifts the curve to the left and a lower$P{O}_2$ is required for haemoglobin to bind a given amount of oxygen.
iii. An increase in the concentration of 2,3 diphosphoglycerate shifts the curve to the right, causing more oxygen to be liberated and vice-versa.
The pH of blood falls as its carbon dioxide content increases so that, when the $PC{O}_2$ rises, the oxygen-haemoglobin dissociation curve shifts to the right side and the $P_{50}$ rises.