Question

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

(a) bacteria are resistant to the toxin

(b) toxin is immature

(c) toxin is inactive

(d) bacteria encloses toxin in a special sac

Answer 1

The Bt-toxin is an inactive (protoxin) toxin inside the organism Bacillus thuringiensis. The acidic pH of the insect's gut converts protoxin to the active toxin.