Question

Identify the incorrect statement about Bt-toxin.

• A. It kills the insects belonging to the orders lepidoptera, coleoptera, and diptera
• B. It is activated by alkaline environment of insect midgut and by activity of protease
• C. It binds to receptors on the epithelial cells of the midgut
• D. It can affect humans too because it can bind to the epithelial cells of their duodenum

Answer 1

The correct option is D It can affect humans too because it can bind to the epithelial cells of their duodenum

Bt-toxin is produced by the bacterium Bacillus thuringiensis. It kills insects of certain orders such as lepidoptera, coleoptera, and diptera by binding to their midgut epithelium cell surface and creating pores causing the death of the insects. It is an inactive protoxin that requires an alkaline medium to solubilize and proteases for activation.

It does not adversly affect humans because the acidic pH of the stomach and the proteolytic enzymes digest it before it passes into the duodenum. Hence, option d is incorrect about the toxin.