In the world of biotechnology and genetic engineering, what is a vector? a) a vector is a type of enzyme made by viruses, used to cut and splice dna fragments. b) a vector is a plasmid or virus used to move foreign genes into desired host cells. c) a vector is a type of gel used to move and separate dna fragments for dna fingerprints. d) a vector is a plasmid or virus used to perform the polymerase chain reaction and make copies of dna.

Ans. Option (B).

In genetic engineering, a vector molecule can be defined as a molecule of DNA, which is used as a vehicle to artificially transport foreign gene or DNA material into another organism (host) or cell, where it can be copied or/and expressed.

To make a recombinant cell or organism, the target DNA is first isolated and then integrated with the vector molecule. The recombinant DNA (having target DNA) is then inserted to host organism where it makes its copies.

A well known example of vector molecule is plasmid DNA, found in many bacterial and some eukaryotic cells.

Thus, the correct answer is option (B).