Question

Each haemoglobin molecule can carry

• A. two molecules of $O_2$
• B. three molecules of $O_2$
• C. four molecules of $O_2$
• D. one molecule of $O_2$

Answer 1

Answer: (C)

Each haemoglobin (Hb) molecule can carry a maximum of four molecules of $O_2$.
$H{b}_4+4O_2\to H{b}_4{O}_8$
Haemoglobin is a red coloured iron containing pigment in the RBCs. Oxygen can bind with haemoglobin in a reversible manner to form oxyhaemoglobin $\left(Hb{O}_2\right)$.