Assertion (A): In the gene gun method, microparticles are typically made of gold or tungsten and coated with the desired DNA.
Reason (R): The gene gun method is only applicable to animal cells and is not used in plant biotechnology.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Assertion (A) is true but Reason (R) is not correct.
Assertion (A): In the gene gun method, microparticles are typically made of gold or tungsten and coated with the desired DNA. — True. In the gene gun (biolistics) method, cells are bombarded with high-velocity micro-particles of gold or tungsten coated with DNA. The particles carry the DNA into the cells.
Reason (R): The gene gun method is only applicable to animal cells and is not used in plant biotechnology. — False. The book describes the gene gun as a method suitable for plants. The method used for animal cells is micro-injection, in which recombinant DNA is injected straight into the nucleus. So R has it the wrong way round.
A is true and R is false.
NCERT Extract:
Competent Host (For Transformation with Recombinant DNA) – “… In a method known as micro-injection, recombinant DNA is directly injected into the nucleus of an animal cell. In another method, suitable for plants, cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA in a method known as biolistics or gene gun.”