Read the Passage carefully and answer the questions.
The DNA 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 separated DNA fragments can be visualised only after staining the DNA with a compound known as ethidium bromide followed by exposure to UV radiation. The repeated amplification of DNA is achieved by the use of a thermostable DNA polymerase (isolated from a bacterium, Thermus aquaticus). After completion of the biosynthetic stage, the product has to be subjected through a series of processes before it is ready for marketing as a finished product. The downstream processing and quality control testing vary from product to product. The convention for naming restriction enzymes is the first letter of the name comes from the genus and the second two letters come from the species of the prokaryotic cell from which they were isolated.
In agarose gel electrophoresis, DNA fragments move towards _____ under an electric field through a medium.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Anode
DNA fragments are negatively charged because of their phosphate groups. In an electric field they move towards the positive electrode, the anode, through the agarose gel; smaller fragments move farther.
Option (1) Cathode — Incorrect. The cathode is the negative electrode, which repels negatively charged DNA.
Option (2) Anode — Correct. DNA is negatively charged, so in an electric field the fragments move towards the anode (positive electrode) through the agarose gel. Smaller fragments move farther.
Option (3) Matrix — Incorrect. The matrix (agarose gel) is the medium the DNA moves through, not where it moves to.
Option (4) Buffer — Incorrect. The buffer carries the current and keeps the pH steady.
Note 1: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. 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 19-05-2026 (Slot 1).