CO combine with haemoglobin and forms

Options

A. oxyhaemoglobin
B. methaemoglobin
C. carbaminohaemoglobin
D. carboxyhaemoglobin

Answer

To solve the question, "CO combines with hemoglobin and forms," we will analyze the options provided and understand the interactions of carbon monoxide (CO) with hemoglobin.

### Step-by-step Solution:

1. **Understanding Hemoglobin**: 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. **Identifying the Options**:
- **Option 1: Oxyhemoglobin**: This is formed when hemoglobin binds with oxygen (O2).
- **Option 2: Methemoglobin**: This occurs when the iron in hemoglobin is oxidized from Fe²⁺ to Fe³⁺, impairing its ability to carry oxygen.
- **Option 3: Carbaminohemoglobin**: This is formed when hemoglobin binds with carbon dioxide (CO2).
- **Option 4: Carboxyhemoglobin**: This is formed when hemoglobin binds with carbon monoxide (CO).

3. **Analyzing the Interaction of CO with Hemoglobin**:
- Carbon monoxide (CO) has a much higher affinity for hemoglobin than oxygen does. When CO binds to hemoglobin, it forms a stable compound known as carboxyhemoglobin.

4. **Conclusion**: Based on the analysis, when CO combines with hemoglobin, it forms **Carboxyhemoglobin**.

5. **Final Answer**: Therefore, the correct answer to the question is **Option 4: Carboxyhemoglobin**.