Question

Bacillus thuringiensis forms protein crystals which contain insecticidal protein. The incorrect statement about this protein is that it

• A. Does not kill the carrier bacterium which is itself resistant to the toxin
• B. Binds with epithelial cells of midgut of the insect pest ultimately killing it
• C. Is cooked by several genes including the gene cry
• D. Is activated by acid pH of the foregut of the insect pest

Answer 1

The correct option is D Is activated by acid pH of the foregut of the insect pest

The Bacillus thuringiensis protein exists as an inactive toxin and is converted into its active form by alkaline pH of the gut of insect which in turn dissolves the protein crystals. The activated toxin then binds to epithelial cells of the midgut, paralyzes the digestive tract which ultimately causes lysis of the cells, finally leading to the death of the insect.

So, option B is the correct answer.