Question

Following are the steps involved in action of toxin in Bt. Cotton
A. The inactive toxin converted into active form due to alkaline pH of gut of insect.
B. Bacillus thuringiensis produce crystals with toxic insecticidal proteins.
C. The alkaline pH solubilises the crystals.
D. The activated toxin binds to the surface of midgut cells, creates pores and causes death of the insect.
E. The toxin proteins exist as inactive protoxins in bacteria.
Choose the correct sequence of steps from the options given below:

• A. E → C → B → A → D
• B. B → C → A → E → D
• C. A → E → B → D → C
• D. B → E → C → A → D

Answer 1

The Correct Option is D

The correct sequence of events:

• Bacillus thuringiensis produces crystals containing inactive protoxins (B).
• These protoxins are initially inactive (E).
• In the alkaline gut of the insect, the crystals dissolve (C).
• The alkaline pH converts the inactive protoxins into their active form (A).
• The active toxin binds to midgut cells, creating pores and causing insect death (D).

Therefore, the correct sequence is:
\[ B\rightarrow E \rightarrow C \rightarrow A \rightarrow D \]