Bt toxin kills the insect by

Options

A. Blocking nerve conduction
B. Damaging the surface of trachea
C. Creating pores in the tracheal system
D. Creating pores in the mid gut

Answer

**Step-by-Step Solution:**

1. **Understanding Bt Toxin**:
- Bt toxin is derived from the bacterium Bacillus thuringiensis. It is a biological pesticide used in agriculture to control insect pests.

2. **Mechanism of Action**:
- When insects consume plants that have been genetically modified to produce Bt toxin (like Bt cotton), the toxin enters their digestive system.

3. **Target Area**:
- The Bt toxin specifically targets the midgut of the insect. The midgut is a crucial part of the insect's digestive system where food is processed.

4. **Formation of Pores**:
- Once the Bt toxin reaches the midgut, it binds to specific receptors on the gut cells. This binding leads to the formation of pores in the midgut lining.

5. **Cell Lysis**:
- The creation of these pores disrupts the integrity of the gut cells, leading to cell lysis (breakdown of the cells). This ultimately causes the insect to stop feeding and leads to its death.

6. **Conclusion**:
- Therefore, the correct answer to the question "Bt toxin kills the insect by" is option D: creating pores in the midgut.