Number of oxygen molecules that can be carried by a molecule of haemoglobin are

Options

A. 2
B. 4
C. 6
D. 8

Answer

To solve the question regarding the number of oxygen molecules that can be carried by a molecule of hemoglobin, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Hemoglobin Structure**:
- Hemoglobin is a protein found in red blood cells (RBCs) that is responsible for transporting oxygen from the lungs to the tissues and carbon dioxide from the tissues back to the lungs.

2. **Oxygen Binding Sites**:
- Each hemoglobin molecule has four binding sites for oxygen. This means that one hemoglobin molecule can bind to four oxygen molecules.

3. **Formation of Oxyhemoglobin**:
- When hemoglobin binds with oxygen, it forms a complex known as oxyhemoglobin. The process of binding is influenced by several factors, including pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), and temperature.

4. **Conclusion**:
- Since one molecule of hemoglobin can bind to four oxygen molecules, the answer to the question is that a single molecule of hemoglobin can carry **4 oxygen molecules**.

### Final Answer:
The number of oxygen molecules that can be carried by a molecule of hemoglobin is **4**. Therefore, the correct option is **B**.

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