Question

Crystals of Bt toxin produced by some bacteria do not kill the bacteria producing them because:

• A. Bacteria are resistant to the toxin
• B. Toxin is immature
• C. Toxin is inactive
• D. Bacteria encloses ‘toxin’ in a special capsule

Hint:

Bt toxin becomes active only in alkaline pH, which is found in insect guts, not inside bacteria.

Answer 1

The Correct Option is C

Step 1: Bacillus thuringiensis} produces a crystalline protein toxin called Bt toxin.
Step 2: The toxin is produced in an inactive form called protoxin.
Step 3: It becomes active only in the alkaline pH of the insect gut.
Step 4: Since the bacteria’s own cytoplasm doesn't activate the toxin, it is not harmed.
\[ \Rightarrow \boxed{\text{Correct answer: (C) Toxin is inactive}} \]