Q.124 Botany ⭐ 360° Option Elimination Active

NEET 2024 Botany Question 124 Solution

Topic: Biotechnology and its Applications · Official NTA Booklet Code T1

Question

Given below are two statements: Statement I: Bt toxins are insect group specific and coded by a gene cry IAc. 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:

(1)Statement I is true but Statement II is false
(2)Statement I is false but Statement II is true
(3)Both Statement I and Statement II are true
(4)Both Statement I and Statement II are false

✓

Verified Against NTA Final Answer Key

Option (1) : Statement I is true but Statement II is false

📚 Biotechnology and its Applications Easy

📋 Given Parameters & Problem Setup

Statement I The Bt toxin proteins encoded by cryIAc control cotton bollworms and are insect group specific.

Statement II The inactive protoxin is converted into an active toxin due to the acidic pH of the insect gut.

⚡

The 30-Second Exam Hall Shortcut: ⚡ Gut pH Activation Rule

⏱️ Save ~20 seconds

Bt toxin crystals are inactive protoxins solubilized and activated by ALKALINE pH in the insect midgut (not acidic pH)! Statement II is false; Statement I is true!

1 Statement I: cryIAc and cryIIAb control cotton bollworms, while cryIAb controls corn borer -> True!

2 Statement II: Inactive protoxin is converted into active toxin due to ALKALINE pH of the insect gut which solubilizes the crystals -> Statement II says acidic pH, which is FALSE!

3 Conclusion: Statement I is true but Statement II is false -> Option (1) / A.

🛡️

Why You Can 100% Trust This Shortcut: NCERT Biology · Biotechnology and its Applications (Bt Cotton and Protoxin Activation)

📐

Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Evaluate Statement I (Cry Gene Specificity)

The Bt toxin is coded by a gene named cry. There are a number of them; for example, the proteins encoded by the genes cryIAc and cryIIAb control cotton bollworms, that of cryIAb controls corn borer. Thus, Statement I is true.

Step 2

Evaluate Statement II (Activation Mechanism)

Bt toxin exists as an inactive protoxin in the bacterium. Once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the ALKALINE pH of the insect midgut which solubilizes the crystals. The activated toxin binds to the surface of midgut epithelial cells, creates pores, causes cell swelling and lysis, leading to death. Statement II erroneously claims acidic pH, making it false.

Step 3

Select Matching Option

Statement I is true but Statement II is false, matching Option (1).

⭐

360° Option Elimination Engine Key Feature

Diagnose every choice: Know exactly why the right option works and why distractors fail.

4-Option Deep Scan

1 (1)

✓ 100% Correct

Verdict & Scientific Reason:

Statement I correctly defines cryIAc specificity; Statement II is false because alkaline pH (not acidic) activates the toxin.

💡

Why this is airtight: None.

2 (2)

✗ Incorrect

Verdict & Scientific Reason:

Statement I is true and Statement II is false.

⚠️

Student Fallacy (Why candidates pick this trap): Statement I is true and Statement II is false.

3 (3)

✗ Incorrect

Verdict & Scientific Reason:

Statement II is false regarding the gut pH.

⚠️

Student Fallacy (Why candidates pick this trap): Statement II is false regarding the gut pH.

4 (4)

✗ Incorrect

Verdict & Scientific Reason:

Statement I is factually correct.

⚠️

Student Fallacy (Why candidates pick this trap): Statement I is factually correct.

⚠️

NTA Trap Alert: Acidic vs Alkaline Insect Gut pH

Assuming digestive juices in insects are acidic like vertebrate stomachs.

🛡️ How to avoid the -1 mark: Insect midgut is distinctly ALKALINE, which is essential for dissolving the alkaline-soluble crystal proteins.

📖

Core NEET Syllabus Standard

Biology Core Botany · Biotechnology and its Applications Standard Benchmark

Core Scientific Principle Tested:

"The Bt toxin protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals. The proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms."

Syllabus Focus: Mechanism of Action of Bacillus thuringiensis (Bt) Endotoxin

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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NEET 2024 Botany Question 124 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ Gut pH Activation Rule

Step-by-Step Rigorous Workflow & Mathematical Proof

Evaluate Statement I (Cry Gene Specificity)

Evaluate Statement II (Activation Mechanism)

Select Matching Option

360° Option Elimination Engine Key Feature

NTA Trap Alert: Acidic vs Alkaline Insect Gut pH

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

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