A pregnant woman is able to transfer oxygen to her fetus because fetal hemoglobin has a greater affinity for oxygen than does adult hemoglobin. Why is the affinity of fetal hemoglobin for oxygen higher
High-Yield Explanation
In adult hemoglobin 2,3-BPG binds to ionized residues in the interface between the two b-chains, thus decreasing the oxygen affinity. The g-chains of fetal hemoglobin have fewer ionized residues in the corresponding interface and bind 2,3-BPG with less affinity, which allows for a greater binding affinity for oxygen. Ref:- Lippincott textbook of Biochemistry