Gel electrophoresis is used for:
- cutting of DNA into fragments
- separation of DNA fragments according to their size
- construction of recombinant DNA by joining with cloning vectors
- isolation of DNA molecule
Answer
(2) separation of DNA fragments according to their size
Solution
As per NCERT, the fragments of DNA are separated by a technique known as gel electrophoresis.
∵ DNA fragments are negatively charged, they move towards the anode through an agarose gel matrix ⇒ they are separated according to their size (sieving effect); smaller fragments move farther.
Cutting is done by restriction endonucleases and joining by DNA ligase.
Answer: (2)