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Biotechnology and its Applications
Mechanism of Action of Bt Toxin
2 questions from 2 papers, each with its answer.
- questions
- 2
- papers
- 2
- years asked, 2017–2026
- 1 of 10
- of Biotechnology and its Applications
- 2.33%
Concepts tested
- Activation of Bt protoxin in the insect gut
- Mechanism of action of Bt toxin
All Questions
2024 1 question
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Given below are two statements: Statement I: Bt toxins are insect group specific and coded by a gene $cry$ IAc. Statement II: Bt toxin exists as inactive protoxin in $B.\ thuringiensis$. However, after ingestion by the insect the inactive protoxin gets converted into active form due to acidic pH of the insect gut. In the light of the above statements, choose the correct answer from the options given below:Statement I: Bt toxins are insect-group specific and are coded by $cry$ genes, e.g. $cry$IAc – true. Statement II: Bt toxin exists as an inactive protoxin in $B.\ thuringiensis$; after ingestion, it is converted into the active form due to the alkaline pH of the insect gut, not acidic – false. So Statement I is true but Statement II is false.
2024 Re-NEET 1 question
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Following are the steps involved in action of toxin in Bt. Cotton. A. The inactive toxin converted into active form due to alkaline pH of gut of insect. B. Bacillus thuringiensis produce crystals with toxic insecticidal proteins. C. The alkaline pH solubilises the crystals. D. The activated toxin binds to the surface of midgut cells, creates pores and causes death of the insect. E. The toxin proteins exist as inactive protoxins in bacteria. Choose the correct sequence of steps from the options given below:Correct sequence: Bacillus thuringiensis produces crystals with toxic insecticidal proteins (B) → these toxin proteins exist as inactive protoxins in the bacteria (E) → the alkaline pH of the insect gut solubilises the crystals (C) → the inactive toxin is converted into active form due to the alkaline pH (A) → the activated toxin binds to midgut cells, creates pores, and kills the insect (D). So the order is B → E → C → A → D.