Read the passage and answer the following question :
The cutting of DNA by restriction endonucleases results in the fragments of DNA. These fragments can be separated by a technique known as gel electrophoresis. Since DNA fragments are negatively charged molecules, they can be separated by forcing them to move towards the anode under an electric field through a medium/matrix. The commonly used matrix is agarose which is a natural polymer extracted from sea weeds. The DNA fragments separate according to their size through sieving effect provided by the agarose gel. Hence, the smaller fragments move farther in the agarose gel. The separated DNA fragments can be visualised only after staining the DNA with ethidium bromide followed by exposure to UV radiation. Bright orange coloured bands of DNA can be observed. The separated bands of DNA are cut out from the agarose gel and extracted from the gel piece. This step is known as elution. The DNA fragments purified in this way are used in constructing recombinant DNA by joining them with cloning vectors.
The DNA fragments formed by treatment with endonuclease are separated by ______________.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Gel Electrophoresis
Option (1) PCR — Incorrect. PCR (polymerase chain reaction) amplifies DNA into many copies; it does not separate fragments.
Option (2) Gel Electrophoresis — Correct. The fragments are forced through agarose gel by an electric field and separate by size.
Option (3) Cloning — Incorrect. Cloning makes many copies of a DNA by putting it into a vector and host.
Option (4) Restriction digestion — Incorrect. Restriction digestion is the step that makes the fragments, before they are separated.
Note 1: This passage is taken from NCERT as it is. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.
Note 2: A similar question was also asked in CUET (UG) 2026 on 29-05-2026 (Slot 2).