Question

I really need help on my biochemistry homework, please show solutions. Thank you sooo much.

Fetal and maternal blood has very different 02 saturation curves when studied under the same conditions. Fetal erythrocytes contain a structural variant of hemoglobin, HbF, consisting of two α and two γ subunits whereas the maternal erythrocytes contain HbA with two α and two β subunits. 4. 10 a) which hemoglobin has a higher affinity for O, under normal conditions? Explain. EA ig

Answer 1

4 a)

From the graph, we see HbF is left shifted compared to HbA. The more the left shift, more is the O₂ affinity. Thus HbF has more O₂ affinity than HbA. By O₂ affinity, we mean the tendency to bind to O₂.

b) The higher the O₂ affnity, the more saturated will be the Hb with O₂. Thus HbF carries more O₂ than HbA at the same O₂ partial pressures.

c) BPG (Bisphosphoglyceric acid) binds with HbA and HbF, decreasing its O₂ affinity, thus releasing O₂ for near by tissues.

When BPG is removed, O₂ affinity increases. The O₂ affinity of HbA increases more than that of HBF on removing BPG.

Thus the strong binding of BPG to HbA than to HbF results in low O₂ affinity of HbA compared to HbF.