In the above represented plasmid an alien piece of DNA is inserted at EcoRI site. Which of the following strategies will be chosen to select the recombinant colonies? 1. Using ampicillin & tetracyclin containing medium plate. 2. Blue color colonies will be selected. 3. White color colonies will be selected. 4. Blue color colonies grown on ampicillin plates can be selected.

Topic: Tools: restriction enzymes, vectors, host· Biotechnology and Its Applications

In the above represented plasmid an alien piece of DNA is inserted at EcoRI site. Which of the following strategies will be chosen to select the recombinant colonies?

Plasmid map with BamHI, Tet R, Ori, EcoRI, beta-Galactosidase, amp

1. Using ampicillin & tetracyclin containing medium plate.

2. Blue color colonies will be selected.

3. White color colonies will be selected.

4. Blue color colonies grown on ampicillin plates can be selected.

Doubtly Asked 30 Oct 2026 NEET UG 2025 Practice test neet Save WhatsApp Report

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Answer: 3. White color colonies will be selected.

Key idea: The figure shows the EcoRI site inside the gene for \(\beta\)-galactosidase.

Inserting alien DNA there inactivates the enzyme (insertional inactivation). With a chromogenic substrate, recombinant colonies stay white, while non-recombinants give blue colonies. So white colonies are selected.

Ampicillin and tetracycline would not distinguish them because the insert is not in the Tet gene. Blue colonies are non-recombinants.

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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In the above represented plasmid an alien piece of DNA is inserted at EcoRI site. Which of the following strategies will be chosen to select the recombinant colonies?

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