Question

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

Answer 1

The term biotechnology can be conceptised to the use of living organisms or their products to modify human health and the human environment. But today with the advancement , it is used in a restricted way to refer only to processes which use genetically modified organisms to achieve the same on a larger scale.

Complete answer:
The ligation of alien DNA is made possible at a restriction site present in one of the two antibiotic resistance genes. For example, you can ligate a DNA which is unknown that is foreign DNA at the BamHI site of tetracycline resistance gene in the vector PBR322. The recombinant plasmids that are now developed will now be free from tetracycline resistance due to insertion of foreign DNA but can now also be selected out from non-recombinant ones by plating the transformant on ampicillin-containing medium.

Now let us know about each term given in questions:
(a) Origin of replication : It is a particular sequence of DNA bases, which initiates replication.A prokaryotic DNA has normally a single origin of replication, while eukaryotic DNA may additionally have greater than one. This sequence controls the copy wide variety of linked DNA. An alien DNA for replication should be linked to the origin of replication

(b) Bioreactors : Bio reactor utilized in biotechnology is generally 100-1000 litre cylindrical metal. container with a curved base to facilitate mixing of contents. The way of life medium containing all nutrients, salts, vitamins, hormones etc. is brought along with an inoculum of changed cells with recombinant DNA. A stirrer helps in mixing and most excellent availability of vitamins to culture cells. Supply of oxygen is maintained if the cells characteristic better beneath aerobic conditions.

(c) Downstream processing : 1) Downstream processing refers to the purification and the healing of biosynthetic products, from natural sources such as animal or plant tissue, fermentation broth, including the recycling and the cure and disposal of waste normally carried out in pharmaceutical industries.

2. The processing starts off evolving with the formation of the authentic product. The product then goes via some tactics earlier than a remaining finished product is equipped for advertising and marketing. The collective of all these tactics comes beneath downstream processing. The methods are following:-

a) The product goes through separation and purification first, then,

b) The product is kept in appropriate preservatives. If tablets are to be manufactured such formulation has to endure medical trials.
c) Finally, a perfect best manipulation testing for each product is additionally needed. It is an essential step in the manufacture of prescribed drugs such as antibiotics,hormones, antibodies and vaccines.

Note: The normal E.coli cells do not carry resistance against any of the antibiotics. Also, the gene lac Z coding for B-galactosidase enzyme may also be used as a selection basis. This enzyme utilises its substrate to produce a blue-coloured product. Therefore, the substrate for B-galactosidase is chromogenic (colour producing).