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.
The downstream processing does not include -
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → No clinical trials in case of drugs
After the product is made in the bioreactor, it goes through downstream processing before it can be sold: separation and purification, formulation with preservatives, clinical trials for drugs, and strict quality control testing.
Option (1) Separation and purification — Part of downstream processing. After the product forms in the bioreactor, it is first separated and purified; the book calls these two processes together downstream processing.
Option (2) Product formulation with preservatives — Part of downstream processing. The product is made ready for storage and use.
Option (3) No clinical trials in case of drugs — Not part of downstream processing. A drug must pass thorough clinical trials; leaving them out is not a step. The word ‘No’ turns a real step into a wrong one.
Option (4) Strict quality control testing — Part of downstream processing. Every product must be tested before it is marketed; the book lists strict quality control testing as a required step.
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.
NCERT Extract:
Downstream Processing – “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 processes include separation and purification, which are collectively referred to as downstream processing. The product has to be formulated with suitable preservatives. Such formulation has to undergo thorough clinical trials as in case of drugs. Strict quality control testing for each product is also required.”