Q.183 Zoology ⭐ 360° Option Elimination Active

NEET 2024 Zoology Question 183 Solution

Topic: Biotechnology: Principles and Processes · Official NTA Booklet Code T1

Question

The following diagram shows restriction sites in E. coli cloning vector pBR322. Find the role of 'X' and 'Y' genes:

✓

Verified Against NTA Final Answer Key

Option (4) : The gene ‘X’ is responsible for controlling the copy number of the linked DNA and ‘Y’ for protein involved in the replication of Plasmid.

📚 Biotechnology: Principles and Processes Medium

📋 Given Parameters & Problem Setup

Vector E. coli cloning vector pBR322

Gene X ori (origin of replication)

Gene Y rop (repressor of primer)

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The 30-Second Exam Hall Shortcut: ⚡ pBR322 Functional Map Identification

⏱️ Save ~30 seconds

In pBR322: X = ori (origin of replication, controls copy number); Y = rop (codes for proteins involved in the replication of the plasmid)! Direct NCERT definition!

1 Identify labels X and Y on standard pBR322 plasmid map:

2 - X is located at the replication origin = ori.

3 - Role of ori: initiates replication and controls copy number of linked DNA.

4 - Y is located near Pvu II = rop.

5 - Role of rop: codes for the proteins involved in the replication of plasmid.

6 Option (4) states: X controls copy number of linked DNA, and Y codes for protein involved in plasmid replication.

7 Select Option (4) / D.

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Why You Can 100% Trust This Shortcut: NCERT Biology · Biotechnology: Principles and Processes (Cloning Vector pBR322 Architecture)

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Step-by-Step Rigorous Workflow & Mathematical Proof

Step 1

Locate Genes on Plasmid pBR322

In the standard genetic map of E. coli cloning vector pBR322 illustrated in NCERT Figure 11.4: - Position X marks the 'ori' (Origin of replication). - Position Y marks the 'rop' (Repressor of primer) gene located between the tetracycline resistance cassette and the Pvu II site.

Step 2

Define Function of Origin of Replication (ori / Gene X)

This is a sequence from where replication starts and any piece of DNA when linked to this sequence can be made to replicate within the host cells. This sequence is also responsible for controlling the copy number of the linked DNA.

Step 3

Define Function of rop (Gene Y)

The rop codes for the proteins involved in the replication of the plasmid (acting as a regulator to modulate copy number).

Step 4

Select Matching Choice

Option (4) provides the precise verbatim NCERT functional definitions.

⭐

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)

✗ Incorrect

Verdict & Scientific Reason:

Inverts and confuses ori with rop; antibiotic resistance genes are ampR and tetR.

⚠️

Student Fallacy (Why candidates pick this trap): Inverts and confuses ori with rop; antibiotic resistance genes are ampR and tetR.

2 (2)

✗ Incorrect

Verdict & Scientific Reason:

Neither X nor Y is an antibiotic resistance gene.

⚠️

Student Fallacy (Why candidates pick this trap): Neither X nor Y is an antibiotic resistance gene.

3 (3)

✗ Incorrect

Verdict & Scientific Reason:

Gene X is ori, not an antibiotic resistance gene.

⚠️

Student Fallacy (Why candidates pick this trap): Gene X is ori, not an antibiotic resistance gene.

4 (4)

✓ 100% Correct

Verdict & Scientific Reason:

Accurately identifies X as ori (controlling copy number) and Y as rop (coding for replication proteins).

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Why this is airtight: None.

⚠️

NTA Trap Alert: ori Copy Number Function Oversight

Remembering that ori starts replication but forgetting that it also controls the copy number of linked foreign DNA.

🛡️ How to avoid the -1 mark: NCERT emphasizes: "This sequence is also responsible for controlling the copy number of the linked DNA."

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Core NEET Syllabus Standard

Biology Core Zoology · Biotechnology: Principles and Processes Standard Benchmark

Core Scientific Principle Tested:

"Origin of replication (ori): This sequence is also responsible for controlling the copy number of the linked DNA... The rop codes for the proteins involved in the replication of the plasmid."

Syllabus Focus: pBR322 Cloning Vector: Roles of ‘ori’ (X) and ‘rop’ (Y) Genes

✓ Core NEET UG Syllabus Anchor Syllabus & Academic Standards ↗

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Vector Anatomy & Features (Ori, Selectable Marker, Cloning Site, Transformation)

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NEET 2024 Zoology Question 183 Solution

Question

The 30-Second Exam Hall Shortcut: ⚡ pBR322 Functional Map Identification

Step-by-Step Rigorous Workflow & Mathematical Proof

Locate Genes on Plasmid pBR322

Define Function of Origin of Replication (ori / Gene X)

Define Function of rop (Gene Y)

Select Matching Choice

360° Option Elimination Engine Key Feature

NTA Trap Alert: ori Copy Number Function Oversight

Core NEET Syllabus Standard

Ready to attempt under real exam pressure?

🔗 Related Questions — Biotechnology: Principles and Processes

Polymerase Chain Reaction (PCR) Steps & Primer Annealing

Plasmids: Nature and Function as Cloning Vectors

Differential Enzymatic Cell Wall Lysis (Lysozyme vs. Cellulase)

Vector Anatomy & Features (Ori, Selectable Marker, Cloning Site, Transformation)

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