Class NEET 2026 ALL Q #2054
COMPETENCY BASED
APPLY
4 Marks 2026 NTA-RE-NEET-2026 MCQ SINGLE
The inactive form of Bt toxin is converted to the active form in the insect gut
(A) by nucleases
(B) due to alkaline pH
(C) due to acidic pH
(D) by proteases
Prev Next
Correct Answer: B

AI Tutor Explanation

Powered by Gemini

Detailed Solution

Step 1: Understanding Bt Toxin

The Bacillus thuringiensis (Bt) bacterium produces insecticidal crystal proteins known as Cry proteins. These proteins exist in an inactive protoxin form within the bacterium.

Step 2: Mechanism of Activation

When an insect ingests the inactive Bt toxin, it enters the midgut of the insect. The midgut environment of the target insect is characterized by a high alkaline pH.

Step 3: Conversion Process

The alkaline pH of the gut solubilizes the crystals, allowing the inactive protoxin to be converted into its active toxic form. This active toxin then binds to the epithelial cells of the midgut, causing cell lysis and eventually the death of the insect.

Final Answer: due to alkaline pH

AI generated content. Review strictly for academic accuracy.

Pedagogical Audit
Bloom's Analysis: This is an APPLY question because it requires the student to recall specific biological mechanisms and apply that knowledge to explain the activation process of a toxin in a specific physiological environment.
Knowledge Dimension: CONCEPTUAL
Justification: The question tests the understanding of the relationship between environmental conditions (pH) and biochemical activation, which is a core concept in Biotechnology.
Syllabus Audit: In the context of NEET, this is classified as COMPETENCY. This question is a standard NCERT-based inquiry frequently appearing in competitive biology exams to test conceptual clarity on Biotechnology applications.

More from this Chapter

MCQ_SINGLE
Consider the following nuclear reaction ${}^{238}U\longrightarrow{}^{234}Th+{}^{4}He$. Take masses of ${}^{238}U$, ${}^{234}Th$ and ${}^{4}He$ as 238.050 u, 234.043 u and 4.003 u, respectively. The Q value for the reaction, in keV, is: [Given: $1~u=931.5~MeV~c^{-2}$]
MCQ_SINGLE
The number of vertebrae in a human is
MCQ_SINGLE
Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Generally, 3d transition metals have high melting points. Reason R: Involvement of 3d-electrons in addition to 3s-electrons in the interatomic metallic bonding. In light of the above statements, choose the most appropriate answer from the options given below:
MCQ_SINGLE
A cylindrical cork of uniform density floats in a liquid of density $\rho_{1}$. If the cork is depressed slightly and released, it oscillates harmonically with time period T. If the same cork floats in another liquid of density $\rho_{2}$, then the similar oscillation has time period 2T. The value of $\rho_{2}/\rho_{1}$ is:
MCQ_SINGLE
Arrange the following elements in descending order of their contribution percentage weight of the human body. (a) Oxygen (b) Carbon (c) Hydrogen (d) Nitrogen Choose the correct answer from the options given below:
View All Questions