Question

What effect will the spores of Bt have on insect pest?

Hint:

The key to Bt toxin activation is the "alkaline pH" of the insect gut. It remains harmless in the acidic/neutral environment of the human stomach.

Answer 1

Step 1: Understanding the Concept:
The Bt toxin is produced as an inactive protoxin and requires specific conditions to become lethal.
Step 2: Detailed Explanation:
1. The insect pest ingests the Bt spores/crystals.
2. In the alkaline pH of the insect's midgut, the inactive protoxin is solubilized and converted into an active toxin.
3. The activated toxin binds to the surface of midgut epithelial cells.
4. It creates pores in the cell membranes, causing cell swelling and lysis.
5. This ultimately leads to the death of the insect.
Step 3: Final Answer:
The spores release a toxin that causes midgut rupture and death of the insect.