A procedure through which a piece of DNA is introduced into a host bacterium is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Transformation
(1) Transformation — Correct. In transformation a piece of DNA, such as a recombinant plasmid, is introduced into a host bacterium. Bacterial cells are first made ‘competent’ (for example with calcium ions) so that the DNA can enter them.
(2) Isolation — Incorrect. Isolation means getting pure DNA out of cells, free from RNA, proteins and other molecules. It is the first step of recombinant DNA technology, not the step of putting DNA into a host.
(3) Extraction — Incorrect. Extraction means taking something out, such as DNA from cells or a product from the culture. It is the opposite of introducing DNA into a host.
(4) Ligation — Incorrect. Ligation is the joining of two DNA pieces by the enzyme DNA ligase. It is done before the recombinant DNA is put into the host.
NCERT Extract:
Cloning Vectors – “… (ii) Selectable marker : In addition to ‘ori’, the vector requires a selectable marker, which helps in identifying and eliminating nontransformants and selectively permitting the growth of the transformants. Transformation is a procedure through which a piece of DNA is introduced in a host bacterium (you will study the process in subsequent section).”