In biolistic method, the cells are bombarded with high velocity microparticles of:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Gold or tungsten coated with DNA
Option (1) DNA coated with gold or tungsten — Incorrect. The DNA coats the metal particles, not the other way round.
Option (2) Gold or tungsten coated with DNA — Correct. In the biolistic (gene gun) method, cells are bombarded with high-velocity microparticles of gold or tungsten coated with DNA. The particles carry the DNA into the cells.
Option (3) Platinum or copper coated with DNA — Incorrect. NCERT names only gold or tungsten as the micro-particles used in biolistics. Platinum and copper are not used, so this option is wrong.
Option (4) Copper or iron coated with DNA — Incorrect. Copper and iron are not the metals used. The micro-particles are of gold or tungsten, coated with the DNA to be put into plant cells.
NCERT Extract:
Cloning Vectors – “… Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 420C (heat shock), and then putting them back on ice. This enables the bacteria to take up the recombinant DNA. This is not the only way to introduce alien DNA into host cells. 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.”