Class 12th Biology 2017 Set3 Delhi Board Paper Solution
Question 19
Why do lepidopterans die when they feed on Bt cotton plant? Explain how does it happen.
Answer
Some strains of Bacillus thuringiensis gene called cry gene produce protein that kill certain insects each as Lepidopterons (tobacco budworms, armyworm, bettles and flies). Bacillus thuringiensis forms protein crystal during a particular phase of their growth. These cystals contain a toxin insecticidal protein.The activated toxin binds to the surface of midget epithelial cells and create pores that causes cell swelling and lysis. The toxin is coded by a gene named cry.
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