Question

Bt toxin kills insects by

• A. Inhibiting protein synthesis
• B. Obstructing biosynthetic pathway
• C. Creating pores in midgut epithelial cells leading to cell swelling and lysis
• D. Generating excessive heat

Hint:

Remember that Bt toxin acts as a biopesticide by causing pore formation in insect midgut epithelial cells. This specificity is why it is safe for humans and other non-target organisms.

Answer 1

The Correct Option is C

Bt (Bacillus thuringiensis) toxin is a crystal protein (Cry protein) that targets the midgut epithelial cells of susceptible insects, particularly Lepidopteran larvae. The toxin binds to receptors on the epithelial cells, forms pores, disrupts osmotic balance, causes cell swelling and lysis, ultimately killing the insect. Bt toxin does not inhibit protein synthesis or generate heat; its primary mode is physical disruption of gut cells.