Which of the following methods of introducing recombinant DNA into host cells is suitable for plants?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Biolistics (gene gun)
Alien DNA can be put into host cells in several ways, and each suits a different kind of cell. Bacteria are made competent and given a heat shock, animal cells receive DNA by micro-injection, and plant cells are bombarded with DNA-coated micro-particles of gold or tungsten, the biolistics or gene gun method.
Option (1) Biolistics (gene gun) — Correct. The book describes the gene gun method as the one suitable for plants.
Option (2) Micro-injection — Incorrect. Micro-injection puts recombinant DNA directly into the nucleus of an animal cell.
Option (3) Disarmed retrovirus vectors — Incorrect. Disarmed retroviruses are used to deliver desirable genes into animal cells, not plant cells.
Option (4) Heat shock of cells kept on ice — Incorrect. Keeping cells on ice and giving them a brief heat shock is used for competent bacterial cells taking up recombinant DNA.
NCERT Extract:
Competent Host (For Transformation with Recombinant DNA) – “… Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice, followed by placing them briefly at 42°C (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.”