Question

Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because –

(a) bacteria are resistant to the toxin.

(b) the toxin is immature.

(c) the toxin is inactive.

(d) bacteria enclose toxins in a special sac.

Answer 1

The correct answer is (c) the toxin is inactive.

Bt toxin is produced by some bacteria as an inactive pro-protein crystal. When insects consume the Bt toxin, it is activated in their gut, releasing the active toxin, which binds to specific receptors in the gut wall, creating holes and ultimately causing the insect to die. The bacteria producing the Bt toxin remain unharmed because they do not have the specific receptors that the toxin binds to.