The haemoglobin of a human foetus
(1) Has a higher affinity for oxygen than that of an adult
(2) Has a lower affinity for oxygen than that of the adult
(3) Its affinity for oxygen is the same as that of an adult
(4) Has only 2 protein subunits instead of 4
Sol. Answer (1)
The haemoglobin of human foetus (HbF) has 4 Heme group and 1 globin. In HbF the
globin protein is made up of 2 and 2 polypeptide chains. Each has 141 amino acids
and each -has 146 amino acids but 37 amino acids in each are different from that of
HbA. It has higher affinity for O2 even at low PO2 and the oxygen -Hb dissociation curve
remains towards the left of normal.