What is the purpose of genetic engineering in biotechnology?

The correct answer is Option (3) → To introduce desirable genes into host organisms

Genetic engineering is a set of techniques that change the genetic material (DNA and RNA) and put it into a host organism, so that the host shows a new trait. Older methods such as hybridisation also bring in many unwanted genes along with the wanted ones. Genetic engineering avoids this: it lets us pick one or a few desirable genes and introduce only them into the target organism.

Option (1) To alter the chemistry of proteins — Incorrect. Genetic engineering alters the chemistry of the genetic material (DNA and RNA), not of proteins directly. Proteins change only as a result of the new gene.

Option (2) To enable asexual reproduction in organisms — Incorrect. Genetic engineering does not aim at asexual reproduction. Its purpose is to move chosen genes into an organism. Asexual reproduction would only make copies with the same genes.

Option (3) To introduce desirable genes into host organisms — Correct. The main use of genetic engineering is to isolate and introduce only the desirable genes into a host, without the undesirable genes that come along in hybridisation.

NCERT Extract:
Principles of Biotechnology – “… Traditional hybridisation procedures used in plant and animal breeding, very often lead to inclusion and multiplication of undesirable genes along with the desired genes. The techniques of genetic engineering which include creation of recombinant DNA, use of gene cloning and gene transfer, overcome this limitation and allows us to isolate and introduce only one or a set of desirable genes without introducing undesirable genes into the target organism.”