In the case of Bacillus thuringiensis , Bacillus itself is not killed by toxic protein crystals produced by it because

Options

A. Bt toxin protein is not produced in Bacillus
B. Bt toxin protein is produced in very less amount in Bacillus
C. Bt toxin exists as inactive toxin
D. Bt toxin cannot cause any damage to Bacillus

Answer

To answer the question of why Bacillus thuringiensis (Bt) is not killed by the toxic protein crystals it produces, we can break down the explanation into several steps:

### Step-by-Step Solution:

1. **Understanding Bacillus thuringiensis**:
- Bacillus thuringiensis is a bacterium that produces a protein known as the Bt toxin, which is toxic to certain insects.

2. **Production of Bt Toxin**:
- The Bt toxin is produced in the form of crystalline proteins. These crystals are not harmful to Bacillus thuringiensis itself.

3. **Inactive State of the Toxin**:
- The Bt toxin exists in an inactive form within the bacterium. This means that while it is produced, it does not pose a threat to the bacterium itself.

4. **Activation of the Toxin**:
- The Bt toxin becomes active only when it is ingested by an insect. Once the toxin is consumed, it interacts with the gut lining of the insect.

5. **Mechanism of Action**:
- Upon ingestion, the inactive Bt toxin is activated in the alkaline environment of the insect's gut. It binds to specific receptors in the gut lining, leading to cell lysis and ultimately causing the death of the insect.

6. **Conclusion**:
- Therefore, Bacillus thuringiensis is not killed by the toxic protein crystals because the toxin is in an inactive form within the bacterium and only becomes active after ingestion by the target insect.

### Final Answer:
Bacillus thuringiensis is not killed by the toxic protein crystals it produces because the Bt toxin exists in an inactive form within the bacterium and is only activated when ingested by the insect.

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