Describe briefly the following :
(a) Origin of replication
(b) Bioreactors
(c) Downstream processing .

Explanation

The downstream processing is an essential step where after completion of the biosynthetic stage of a drug, 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 called downstream processing. The product has to be formulated with suitable preservatives. Such formulation has to undergo thorough clinical trials as in case of durgs. Strict quality control testing for each product is also required.