CO is harmful because

Options

A. It forms stable compound with hemoglobin
B. It blocks mitosis
C. It is mutagenic
D. It causes defoliation

Answer

### Step-by-Step Solution:

1. **Understanding Carbon Monoxide (CO)**:
- Carbon monoxide is a colorless, odorless gas that can be harmful when inhaled.

2. **Role of Hemoglobin**:
- Hemoglobin is a respiratory pigment found in red blood cells (RBCs) that binds to oxygen in the lungs and transports it to tissues throughout the body.

3. **Mechanism of CO Harmfulness**:
- When carbon monoxide is inhaled, it competes with oxygen for binding sites on hemoglobin.
- CO binds to hemoglobin much more strongly than oxygen does.

4. **Formation of Carboxyhemoglobin**:
- The binding of CO to hemoglobin results in the formation of a stable compound known as carboxyhemoglobin.
- This compound prevents hemoglobin from carrying oxygen.

5. **Consequences of CO Binding**:
- With hemoglobin occupied by carbon monoxide, there is less hemoglobin available to transport oxygen.
- This leads to oxygen deficiency in tissues, which is referred to as carbon monoxide poisoning.

6. **Health Effects**:
- Symptoms of carbon monoxide poisoning can include headaches, dizziness, confusion, and in severe cases, unconsciousness or death.

7. **Conclusion**:
- Therefore, carbon monoxide is harmful primarily because it forms a stable compound with hemoglobin, inhibiting the transport of oxygen in the body.