Question

Which of the following statement is incorrect for the Bt toxin protein?

• A. They are produced in active form
• B. They interact with specific receptors located on the host cell surface
• C. They are encoded by cry genes
• D. They are used as insecticides

Answer 1

The correct option is A They are produced in active form

The Bt toxin protein encoded by cry gene is obatined from Bacillus thuringiensis.
The Bt toxin protein is produced as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals. The activated toxin binds to the surface of the midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of the insect. So, this Bt toxin protein can be used as insect-specific insecticides.