Question

The oxygen haemoglobin dissociation curve shifts either to right or left according to various factors. Shift to right indicates dissociation of oxygen from haemoglobin. Which of the following factors will shift the curve to the right?
(i) Decrease in partial pressure of oxygen.
(ii) Increase in partial pressure of $C{O}_2$
(iii) Decrease in hydrogen ion concentration
(iv) Increase in $pH$
(v) Increase in body temperature

• A. (i), (ii) and (v)
• B. (i) and (ii)
• C. (ii) only
• D. (iii) and (iv)

Answer 1

The correct option is A (i), (ii) and (v)

A graph plotted between $O_2$ concentration and percentage saturation of haemoglobin is called Oxygen Dissociation curve.
Shift of curve to left means that there is an increase in affinity between $O_2$ and Hb while Shift to Right means that there is decrease in affinity between $O_2$ and Hb and dissociation of oxyhemoglobin.
In tissue, following conditions are favorable for dissociation of oxygen from oxyhemoglobin:-
(i) Low $P{O}_2$
(ii) High $PC{O}_2$
(iii) High $H^{+}$ concentration
(iv) Low $pH$
(v) Higher temperature

So (i), (ii) and (v) are the factors that will shift the curve to the right.
(iii) and (iv) are the factors that will shift the curve to the left as they are favorable for the formation of oxyhemoglobin.

So, the correct answer is option-c.