Question

Statement I: Bt toxins are insect group specific and coded by a gene cry IAс.

Statement II: Bt toxin exists as inactive protoxin in B. thuringiensis. However, after ingestion by the insect the inactive protoxin gets converted into active form due to acidic pH of the insect gut.

In the light of the above statements, choose the correct answer from the options given below:

Options

• Statement I is true but Statement II is false.

• Statement I is false but Statement II is true.

• Statement I is false but Statement II is true.

• Both Statement I and Statement II are false.

Answer 1

Statement I is true but Statement II is false.

Explanation:

Bt poisons are encoded by several cry genes, including cry IAc, and are in fact specific to insect groups. Bacillus thuringiensis (Bt) bacteria produce Bt toxins as dormant protoxins. When these protoxins are consumed by vulnerable insects, their active forms, which are poisonous to the insect, are activated by the alkaline pH of the insect’s stomach.