[Campbell Biology P.1000] Based on the provided graph illustrating O2 saturation of hemoglobi... | Practice Question

Based on the provided graph illustrating O2 saturation of hemoglobin % , which statement accurately describes the difference between fetal and adult hemoglobin dissociation curves and its physiological significance?

  • A: Fetal hemoglobin has a lower affinity for O2 than adult hemoglobin, facilitating O2 release to the fetus.
  • B: Fetal hemoglobin has a higher affinity for O2 than adult hemoglobin, allowing it to extract O2 from the mother's blood.
  • C: Adult hemoglobin has a higher affinity for O2 than fetal hemoglobin, ensuring the mother retains sufficient O2.
  • D: Both hemoglobins have the same O2 affinity, and the difference in O2 transfer is due to a pH gradient.

Explanation

The fetal hemoglobin dissociation curve is shifted to the left compared to the adult curve, indicating that fetal hemoglobin has a higher affinity for oxygen. This higher affinity allows the fetus to effectively extract oxygen from the mother's blood, which has a lower partial pressure of oxygen PO2 after passing through the placenta.