NEET2008ZoologyBreathing and Exchange of GasesActual
The haemoglobin of a human foetus
Options
- AHas a higher affinity for oxygen than that of an adult
- BHas a lower affinity for oxygen than that of the adult
- CIts affinity for oxygen is the same as that of an adult
- DHas only 2 protein subunits instead of 4
Correct answer
A. Has a higher affinity for oxygen than that of an adult
Step-by-step solution
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 O ₂ even at low PO ₂ and the oxygen - Hb dissociation curve remains towards the left of normal.