Question

Plasmids are the suitable vectors for genetic cloning as

• A. They are indispensable.
• B. They are self replicating units.
• C. They are essential for bacterial reproduction.
• D. None of the above.

Answer 1

The correct option is B They are self replicating units.

A plasmid is a small circular DNA molecule, within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small, circular, double-stranded DNA molecules. Plasmids are considered replicons, a unit of DNA capable of replicating autonomously within a suitable host. Plasmids are the most commonly used bacterial cloning vectors. These cloning vectors contains a site that allows DNA fragments to be inserted, e.g., a multiple cloning site or polylinker which has several commonly-used restriction sites to which DNA fragments may be ligated. A plasmid cloning vector is used to clone DNA fragments of up to 15 kbp.
So, the correct answer is option B.