Question

Go through the following statements

(i) The oxygen-haemoglobin dissociation curve is a sigmoid curve.
(ii) About $4.5$ ml of $C{O}_2$ can combine with Hb in $100$ ml of blood in the form of carbamino- haemoglobin.
(iii) High $p{O}_2$ tends to displace $C{O}_2$ from haemoglobin and this is called the Haldane effect.
(iv) The movement of chloride ions from plasma into RBCs at the time of $C{O}_2$ transport is called Hamburger’s phenomenon.

Which of these are correct?

• A. All are correct.
• B. (i), (ii) and (iii)
• C. (ii), (iii) and (iv)
• D. (i), (iii) and (iv)

Answer 1

The correct option is D (i), (iii) and (iv)

Statement (ii): The oxygen-haemoglobin dissociation curve is a sigmoid curve.
Elaboration: The oxygen-haemoglobin dissociation curve represents the relation between the partial pressure of $O_2$ in the blood and the saturation of haemoglobin with oxygen. The normal oxygen-haemoglobin dissociation curve is sigmoid in shape and the change in external factors moves the curve towards left or right. Hence, the given statement (i) is correct.
Statement (ii): High $p{O}_2$tends to displace $C{O}_2$ from haemoglobin and this is called the Haldane effect.
Elaboration: The Haldane effect states that the increase in the arterial partial pressure of $O_2\left(P{O}_2\right)$ reduces the affinity of $C{O}_2$ with haemoglobin. Hence, the given statement (iii) is correct.
Statement (ii): The movement of chloride ions from plasma into RBCs at the time of $C{O}_2$ transport is called Hamburger’s phenomenon.
Elaboration: The chloride shift or Hamburger’s phenomenon refers to the movement of chloride ions $\left(C{l}^{-}\right)$ in exchange of bicarbonate ions $\left(HCO{3}^{-}\right)$ from the plasma into the RBCs at the time of transportation of $C{O}_2$. Hence, the given statement (iv) is correct.

Hence, option B is correct.