#DNA cloning

ZOOLOGY

Which enzyme is used to produce sticky ends in a DNA fragment?

Restriction endonucleases cut DNA at specific sequences, generating sticky ends for recombination. This follows from latest NCERT 2026-27 principle explaining the concept clearly for NEET students in simple steps as per rationalized syllabus.

Ref: NCERT Biology Textbook - Latest Edition for Academic Session 2026-27 (Zoology section, Rationalized Textbook for Class XI and XII), Chapter: Biology - Zoology portion (Latest NCERT Textbooks for Academic Session 2026-27 - Rationalized Edition for Class XI and XII), Topic: Structural organization, physiology, human health and related concepts as per latest syllabus.

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Polymerase Chain Reaction - PCR and Applications

Which of the following is an advantage of PCR over traditional cloning methods?

PCR is a rapid method that can amplify DNA sequences within hours, unlike traditional cloning, which takes days or weeks.

Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Polymerase Chain Reaction - PCR and Applications

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Polymerase Chain Reaction - PCR and Applications

Which of the following is a key advantage of PCR over traditional cloning methods?

PCR is a rapid method for amplifying DNA sequences within hours, unlike traditional cloning, which takes days or weeks.

Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Polymerase Chain Reaction - PCR and Applications

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Competent Host and Gene Transfer Methods

Which process is used to transfer recombinant DNA into bacterial cells?

Transformation is the process by which recombinant DNA is introduced into bacterial cells.

Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Competent Host and Gene Transfer Methods

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Tools - Restriction Enzymes - Molecular Scissors

Which enzyme is used to produce sticky ends in a DNA fragment?

Restriction endonucleases cut DNA at specific sequences, generating sticky ends for recombination.

Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Tools - Restriction Enzymes - Molecular Scissors

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Principles of Biotechnology - Genetic Engineering

Which of the following statements about plasmids is correct?

Plasmids are extra-chromosomal, circular DNA molecules that replicate independently and are commonly used as vectors.

Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Principles of Biotechnology - Genetic Engineering

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Principles of Biotechnology - Genetic Engineering

Which feature allows plasmids to be used as vectors in genetic engineering?

Plasmids are widely used as vectors because they replicate independently of the host chromosome, allowing gene cloning.

Ref: NCERT Class 12 Biology Chapter 9: Biotechnology: Principles and Processes Principles of Biotechnology - Genetic Engineering

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Restriction Enzyme and Vector

Which vector is best for cloning 200 kb DNA?

Cloning capacity is determined by vector structure and host tolerance for large inserts. Plasmids handle up to 10 kb, lambda phage 20 kb, cosmid around 45 kb, BAC 100-300 kb, YAC 100-2000 kb and mammalian artificial chromosome exceeds 2000 kb. For 200 kb genomic fragments, YAC is optimal among common options because it includes centromere, telomeres and ARS enabling segregation of very large linear eukaryotic DNA in yeast. BAC can accommodate up to 300 kb but 200 kb near upper limit with lower stability. YAC accommodates megabase inserts essential for genome mapping projects.

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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Restriction Digestion & Mapping

Which orientation mapping type shows same size bands in both cuts?

Orientation mapping checks whether insert integrated in forward or reverse direction relative to vector using asymmetric internal restriction site within insert. However when insertion occurs without orientation-specific asymmetry, or when insert lacks internal asymmetry, some digests may produce fragments of identical size irrespective of orientation. Specific patterns where same-size bands appear in both possible orientations indicate that enzyme combination does not distinguish direction, often due to centrally located site or symmetrical arrangement. Such scenario is described as right or correct orientation yielding same size bands.

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

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