Question

Which of the following is not a method of introducing alien DNA into host cells.
(a) Microinjection
(b) Electroporation
(c) Being placed along with the cell into a gene gun
(d) Gel Electrophoresis

Answer 1

Hint: In the above-provided options only one technique of genetic engineering is provided which is used for separating DNA fragments and not for inducing foreign DNA. In this technique electronic current is passed through the gel to charge the fragments of DNA.

Correct answer:
The Gel Electrophoresis technique is not the method of introducing alien DNA into the cells of a host. A technique of separating DNA fragments on the basis of their size is known as gel electrophoresis. In this technique, the DNA samples are loaded into wells. In wells or indentations, one end of DNA samples is connected at one end of a gel, and then an electric current is applied to pull them through the gel. As a result, the DNA fragments get charged negatively and so they start moving towards the positive electrode. The small fragments move through the gel faster than large ones because all DNA fragments have the same amount of charge per mass. Thus the DNA fragments get separated on the basis of their size.

Additional Information:
-Microinjection: This is a technique of introducing alien DNA directly into the host cells with the help of microinjection.
-Electroporation: In the technique of Electroporation pores are created in the cell membrane and in this way the permeability of the cell membrane is increased. This will result in an easy entry of foreign or alien DNA into the cells.
-Gene gun: The technique of gene gun is used to introduce alien DNA into host cells through microprojectile particles.
-The gene gun device is also known as a biolistic particle delivery system. With this gun the gold or tungsten coated DNA particles are bombarded using mechanical force with the host cells and thus the alien DNA enters the host cells.
-Almost any type of cell can be transformed by a gene gun.

So, the correct answer is, 'Gel electrophoresis'.

Note:
-Not only the nucleus of the gene gun device can transform organelles, like plastids and mitochondria also.
-Electroporation technique increases the cell permeability by forming various pores in the cell membrane.
-The gel electrophoresis technique is mainly used to separate DNA fragments on the basis of their sizes for use in genetic engineering.