Biotechnology and Its Applications Question 6
6. In Bt cotton, the Bt toxin present in plant tissue as pro-toxin is converted into active toxin due to:
(a) Acidic $pH$ of the insect gut
(b) Action of gut micro-organisms
(c) Presence of conversion factors in insect gut
(d) Alkaline $pH$ of the insect gut
Show Answer
Answer : d
Hints & Solutions
(d) $B t$ toxin are solubilised in alkaline $pH$ of the insect gut causing death. The Bt toxin protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline $pH$ of the gut which solubilise the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis and eventually cause death of the insect.
