Biology · Biotechnology: Principles and Processes · NEET
After the biosynthetic (production) stage in the bioreactor is finished, the product cannot be sold as it is. It is mixed with cells, medium and waste. Downstream processing is the group of steps that separate the product and purify it, and then make it ready for market. NCERT names two core processes: separation and purification. These two together are called downstream processing.
No. Expression means the foreign gene making the protein product. That happens DURING production (the biosynthetic stage), so it is upstream, not downstream. This is a classic NEET trap. Downstream starts only AFTER the product is already made. So if a question lists Separation, Purification, Preservation and Expression, the odd one out (NOT downstream) is Expression.
NCERT says the product is then formulated with suitable preservatives, tested in clinical trials (like drugs) and passed through strict quality control. These finishing steps come after separation and purification. In NEET, the TWO words NCERT directly labels as downstream processing are separation and purification, but formulation, preservatives and quality control are part of the same after-production stage. Read the option list carefully - if 'preservation' and 'expression' are both options, expression is the wrong (non-downstream) one.
Upstream = everything up to and including making the product: preparing the host cell, medium, growing the culture in the bioreactor, and the gene expressing the product. Downstream = everything after the product is made: separation, purification, formulation, quality control. Simple line: upstream MAKES the product, downstream CLEANS and PACKS it.
No. NCERT clearly states that the downstream processing and quality control testing vary from product to product. A vaccine, an enzyme and an antibiotic each need different purification and testing steps. So there is no single fixed downstream method for all products.
Which of the following is not a component of downstream processing?
The process of separation and purification of expressed protein before marketing is called
Stirred-tank bioreactors have been designed for
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Separation and purification. NCERT states these two processes are 'collectively referred to as downstream processing'. After this, the product is formulated with preservatives and passed through clinical trials and quality control.
No. The bioreactor is where the product is MADE (biosynthetic stage). Downstream processing begins only after the product is made, to separate and purify it and prepare it for market.
NEET repeatedly asks the 'odd one out' style question where Expression is falsely included as a downstream step. Knowing that downstream = separation + purification (after production) lets you eliminate expression instantly. It has been asked in 2016 and 2017.
Yes, in the wider sense. NCERT says after separation and purification the product is formulated with preservatives, undergoes clinical trials and strict quality control, and these vary from product to product. The two words NCERT directly labels as downstream processing are separation and purification.
The biosynthetic (production) stage inside the bioreactor, where the host cells grow and express the desired product. Once this is complete, downstream processing takes over.
