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 the nomenclature of restriction enzymes -
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → The first letter of the name from the genus and the second two letters from the species of the prokaryotic cell
Restriction enzymes are named after the bacterium they come from. In EcoRI, for example, ‘E’ comes from the genus Escherichia and ‘co’ from the species coli; ‘R’ is the strain RY 13, and the Roman number shows the order in which enzymes were isolated from that strain.
Option (1) The first letter of the name from the species and the second two letters from the different species of the prokaryotic cell — Incorrect. The name comes from one bacterium, not two species.
Option (2) The first two letter of the name from the genus and the third letter from the species of the prokaryotic cell — Incorrect. It gives the genus two letters; the genus gives only one.
Option (3) The first letter of the name from the species and the second two letters from the genus of the prokaryotic cell — Incorrect. The order is reversed: genus first, then species.
Option (4) The first letter of the name from the genus and the second two letters from the species of the prokaryotic cell — Correct. A restriction enzyme’s name has the first letter from the genus and the next two letters from the species of the prokaryote it was isolated from. EcoRI comes from Escherichia coli RY 13: E from the genus, co from the species.
Note: 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.