transgenic crops

Question

Bt cotton resists insect pests due to expression of:

RankGuru · Accepted Answer

1. **Source**: *Bacillus thuringiensis* ($Bt$) is a soil bacterium that produces certain proteins during a specific phase of their growth.
2. **The Toxin**: These proteins form crystalline inclusions and are called **Cry proteins** (pro-toxins).
3. **Activation**: When an insect (like cotton bollworm) ingests the toxin, it is converted into an active form due to the **alkaline pH** of the insect's midgut.
4. **Damage**: The active toxin binds to the surface of midgut epithelial cells, creates pores, and causes cell swelling and lysis, eventually killing the insect.
5. **Engineering**: The *cry* genes are isolated and incorporated into the cotton genome to create pest-resistant Bt cotton.

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transgenic crops

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