The hemoglobin of a human fetus

Options

A. Has only 2 protein subunits instead of 4
B. Has a higher affinity for oxygen than that of an adult
C. Has a lower affinity for oxygen than that of the adult
D. Its affinity for oxygen is the same as that of an adult

Explanation

**Step-by-Step Solution:**

1. **Understanding Hemoglobin Structure:**
- Hemoglobin is a protein made up of four subunits in adults, typically two alpha and two beta chains. In contrast, fetal hemoglobin (HbF) consists of two alpha and two gamma chains.

2. **Comparing Affinity for Oxygen:**
- Fetal hemoglobin has a higher affinity for oxygen compared to adult hemoglobin (HbA). This means that HbF can bind oxygen more readily than HbA.

3. **Importance of Higher Affinity:**
- The higher affinity of fetal hemoglobin is crucial for the fetus because it allows for effective oxygen uptake from the mother's blood through the placenta. The placenta serves as the interface for oxygen transfer from mother to fetus.

4. **Mechanism of Oxygen Transfer:**
- When maternal blood passes through the placenta, oxygen binds to fetal hemoglobin due to its higher affinity. This ensures that the fetus receives sufficient oxygen for development, even in a relatively low-oxygen environment.

5. **Conclusion:**
- Therefore, the correct statement regarding the hemoglobin of a human fetus is that it has a higher affinity for oxygen than that of an adult.

**Final Answer:**
The hemoglobin of a human fetus has a higher affinity for oxygen than that of an adult.

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