If a developing fetus made beta hemoglobin subunits instead of gamma hemoglobin subunits, what would be MOST likely to occur?
a. The fetus would extract O2 from its mother’s blood more effectively.
b. The fetal hemoglobin would no longer demonstrate cooperativity.
c. The fetal hemoglobin would become saturated with CO.
d. The fetus would be less susceptible to sickle cell anemia.
e. The fetus would not be able to extract O2 from its mother’s blood as effectively.
The correct answer and explanation is:
The correct answer is e. The fetus would not be able to extract O2 from its mother’s blood as effectively.
Fetal hemoglobin (HbF) is different from adult hemoglobin (HbA) in its structure, primarily due to the substitution of gamma hemoglobin subunits in place of the beta subunits in adults. This difference in structure allows fetal hemoglobin to have a higher affinity for oxygen, which is critical for extracting oxygen from the mother’s blood in the placenta. The higher oxygen affinity ensures that oxygen can be transferred from the maternal blood, which has a lower affinity for oxygen, to the fetal blood.
If a developing fetus were to produce beta hemoglobin subunits instead of gamma subunits, the hemoglobin produced would be more similar to adult hemoglobin (HbA) than fetal hemoglobin. Adult hemoglobin has a lower affinity for oxygen compared to fetal hemoglobin. This lower affinity would make it more difficult for the fetus to extract oxygen from the mother’s blood, leading to less efficient oxygen transfer. The fetus would not be able to take in oxygen as effectively, which could result in hypoxia or other complications due to insufficient oxygen supply.
This change would hinder the essential function of fetal hemoglobin, which is to facilitate oxygen transfer in a low-oxygen environment like the placenta. Therefore, the fetus would not be able to extract oxygen from its mother’s blood as efficiently if it produced beta hemoglobin subunits instead of gamma subunits.