NEETZoologyBiotechnology and Its Applications
When an insect pest ingests the inactive Bt protoxin from a transgenic plant, what physiological trigger activates the toxin, and what is its direct cellular effect?
Options
- AThe acidic pH of the gut solubilises the crystals, and the active toxin acts as a neurotoxin.
- BThe alkaline pH of the gut solubilises the crystals, and the active toxin inhibits protein synthesis in the mi
- CThe alkaline pH of the gut solubilises the crystals, and the active toxin creates pores in the midgut epitheli
- DThe acidic pH of the gut solubilises the crystals, and the active toxin creates pores in the midgut epithelial
Correct answer
C. The alkaline pH of the gut solubilises the crystals, and the active toxin creates pores in the midgut epitheli
Step-by-step solution
The Bt toxin is ingested by the insect in an inactive protoxin form. It is converted into an active form due to the alkaline pH of the insect gut, which solubilises the crystals. The activated toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis, eventually leading to the death of the insect. Acidic pH is incorrect as it does not solubilise the crystals in this context. The toxin does not act by inhibiting protein synthesis or functioning as a neurotoxin. Answer