the haemoglobin of a human foetus

Options

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

Answer

### Step-by-Step Text Solution:

1. **Understanding Hemoglobin Types**:
- There are two types of hemoglobin in humans: adult hemoglobin (HbA) and fetal hemoglobin (HbF).

2. **Structure of Hemoglobin**:
- Adult hemoglobin (HbA) is composed of two alpha (α) chains and two beta (β) chains, making it a tetramer.
- Fetal hemoglobin (HbF), on the other hand, consists of two alpha (α) chains and two gamma (γ) chains, which is a key structural difference.

3. **Production Sites**:
- Adult hemoglobin is primarily produced in the red bone marrow.
- Fetal hemoglobin is mainly produced in the liver and spleen of the fetus.

4. **Oxygen Affinity**:
- Fetal hemoglobin has a higher affinity for oxygen compared to adult hemoglobin. This allows the fetus to extract oxygen from maternal blood more efficiently, which is crucial for its development.

5. **Correct Answer**:
- Based on the differences outlined, the correct statement regarding fetal hemoglobin is that it has a higher affinity for oxygen than adult hemoglobin.