Question

Plasmids are vectors for gene cloning because they

• A. Replicate freely outside bacterial cells
• B. Can be multiplied in culture
• C. Self replicate in bacterial cells
• D. Can be multiplied in laboratories using enzymes

Answer 1

The correct option is C Self replicate in bacterial cells

Gene cloning
Gene cloning is a method of molecular biology used to make multiple copies of a particular gene of interest.

The gene of interest is inserted into a self replicating vector DNA via genetic engineering to form a recombinant DNA (rDNA). The rDNA is then inserted into a host organism to make clones of the gene of interest.

Vector
Vectors are the DNA molecules which can carry the foreign DNA fragment into the host cells for cloning. Examples include
plasmids.

Plasmids
Plasmids are extranuclear, circular double stranded DNA that can self replicate. As a result they are used as vectors to carry the desired gene into the host cell. Plasmids cannot replicate outside a cell as they require host cell machinery to replicate. Therefore they cannot be cultured in a nutrient medium in labs unless present inside a host cell.

Final answer:
a. Self replicate in bacterial cells