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Biotechnology and its Applications — BIOLOGY STD 12 Science — Question

Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYBiotechnology and its Applications3 Marks
Question
What are 'cry-proteins'? Explain with the help of a suitable example how it works as a biopesticide.
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Answer

The toxic insecticidal protein produced by Bacillus thuringiensis at a special stage of growth is called cry protein. The gene encoding this protein is called 'Cry'. This protein is in the form of inactive poison and as soon as the insect eats this inactive poison, the particles of this protein become soluble due to alkaline pH in the intestine of the insect and get converted into active form and stick to the lining of the middle intestine. Create holes due to which the cells swell and burst and the insect dies. This property of BT has been used in many crop plants like cotton, maize, paddy etc. in which BT toxin genes get cloned from bacteria and create resistance against insects/pests in these plants. For example :
(i) CryI AC controls cotton bollworm. (ii) CryI ab controls corn borer.

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