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Some of the characteristics of Bt-cotton are :A. long fibre and resistance to aphidsB. medium yield, long fibre and resistance to beetie pestsC. high yield and production of toxin protein crystals which kill dipteran pestsD. High yield and resistance to bollworms |
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Answer» Correct Answer - C Bacullus Thurringiensis forms crystals containing a toxic insecticidal protein. Bt toxin protein exists as inactive protein but once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut, which solubulise the crystals. The activated toxin binds to the surface of midgur epithelial cells and creates pores that cause cells swelling and lysis and eventually cause death of the insect. specific Bt toxin genes were isolated from B. thuringiensis and incorporated into the sevaral plants suchh as cotton. The toxin is coded by a gene named cryi. there are a number of them, e.g. the proteins encoded by the genes cry I Ac and cry II Ab control the cotton bolloworms, that of cry I Ab control corn borers. |
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