Question

Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes?
A.Lambda phage
B.Retrovirus
C.pBR322
D.Ti plasmid

Answer 1

Hint: We know that we use certain methods to transfer a DNA fragment into the desired cell with the help of vectors. These act as vehicles to carry the genetic information coded in the DNA and deliver them to the cell. Some of them have the ability to multiply within the cell and are called cloning vectors.

Complete answer:
We use several methods to transfer an alien piece of DNA to the host cell.
The plasmid is the double-stranded circular DNA in bacteria. They are modified into a cloning vector and are used to deliver genes to the desired cell.
Bacteriophages are the viruses that infect bacteria. Know that we use several phage vectors for transferring DNA into animal cells. The DNA of retrovirus is used as a vector as it has the ability to induce cancer. It is introduced to the host after the virus is disarmed and cannot cause cancer in the host cell. So, we deliver a piece of DNA into human lymphocytes with the help of retrovirus that acts as phage vectors.
Cosmid vectors are artificially prepared vectors by inserting a DNA sequence into a plasmid from T phage. Keep in mind that T phage is a type of bacteriophage.
There are vectors that are able to replicate both in bacteria and yeast. They are called shuttle vectors.
Transposons are types of DNA that get transferred from one location to another. These are also used as vectors. Keep in mind that transposons are also called jumping genes.

Hence, the correct option is B.

Note: We know that Ti plasmid which is able to induce tumour is present in organisms called Agrobacterium tumefaciens. They are pathogens that infect plants. These pathogens induce this tumour inducing genes and induces tumours in the plant body. These tumour inducing plasmids are modified into cloning vectors that can deliver genes into plant cells.