Bt-crops are not affected by Bt-toxin because (a) Toxin...

Bt-crops are not affected by Bt-toxin because
(a) Toxin exist as inactive protoxin.
(b) It has special antibodies against toxin.
(c) Its intracellular medium is alkaline so toxin remains inactive.
(d) All the above

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Key Concepts

Host Specificity

The specificity of biological toxins relies on differences between target and non-target organisms. Factors such as the presence of specific receptors, the pH of the environment, and the activity of digestive enzymes determine whether a protoxin will be activated and exert its toxic effect. In this way, Bt toxin selectively affects insect pests while leaving non-target organisms like Bt-crops unharmed.

Protoxin Activation

Many biological toxins, including those from Bacillus thuringiensis (Bt), are initially produced in an inactive form known as a protoxin. This protoxin must be processed by enzymes to become active, a conversion that typically occurs under specific conditions such as those found in the digestive systems of target insects.

pH-dependent Activation

The conversion of protoxins into their active toxin forms is often dependent on pH levels. In the case of Bt toxin, the alkaline environment of an insect’s gut is crucial for triggering the proteolytic activation of the protoxin, while other environments, such as the intracellular medium of plants, do not provide the necessary pH for this conversion.

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