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प्रश्न
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because ______.
विकल्प
bacteria are resistant to the toxin
toxin is immature
toxin is inactive
bacteria encloses toxin in a special sac
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उत्तर
Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because toxin is inactive.
Explanation:
Bacillus thuringiensis produces protein crystals during a particular phase of its growth. These crystals have a deadly insecticidal protein. The Bt toxin protein exists as inactive protoxins; however, when an insect consumes the inactive toxin, it is transformed into an active form due to the alkaline pH of the insect’s stomach, which solubilises the crystals. The active toxin adheres to the surface of midgut epithelial cells, causing cell swelling and lysis, eventually leading to the insect’s death, although it does not harm Bacillus.
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Key for lepidopteran insect pest species
 |
Species I |
 |
Species II |
 |
Species III |
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