Revision: Biotechnology >> Biotechnology - Principles and Processes Biology Science (English Medium) Class 12 CBSE

The technique of bringing about improvements in living organisms by genetic modifications and hybridization, for the welfare of human beings is known as ‘Biotechnology’.

The European Federation of Biotechnology (EFB) defined biotechnology as ‘the integration of natural science and organisms, cells, parts thereof, and molecular analogues for products and services.’

• Biotechnology is the use of biological systems, cells, and organisms to develop useful products and services for human welfare.
• The term biotechnology was coined by Karl Ereky (1919).
• Traditional biotechnology involves small-scale processes like fermentation (e.g., curd, cheese, wine), while modern biotechnology is large-scale and based on genetic engineering.
• Modern biotechnology was advanced by recombinant DNA (rDNA) technology developed by Cohen and Boyer (1973).
• It involves techniques like gene modification, PCR, and tissue culture, and integrates fields like molecular biology and genetics.
• Biotechnology has wide applications in agriculture and medicine, such as the production of antibiotics, vaccines, insulin, and the development of high-yield and disease-resistant crops.

• Two Core Techniques — Modern biotechnology is based on (i) Genetic Engineering and (ii) Chemical Engineering.
• Genetic Engineering — Deals with the alteration of DNA and RNA to achieve desired results in a directed, predetermined way using in vitro processes.
• Chemical Engineering — Maintains a sterile environment for manufacturing useful products like vaccines, antibodies, enzymes, vitamins, and therapeutics.
• What Genetic Engineering Involves — Repairing/replacing defective genes, synthesising new genes, transferring genes, combining genes from two organisms, and altering genotype.
• Other Names for Genetic Engineering — Also called Recombinant DNA (rDNA) Technology or Gene Cloning, as it involves transferring a gene via a suitable vector to a new location or organism.

1. Isolation of DNA:
   Genetic material (DNA) is extracted and purified from the source organism by removing proteins, RNA, lipids, and other impurities.
2. Cutting and Separation of DNA:
   DNA is cut at specific sites using restriction endonucleases, and desired fragments are separated by gel electrophoresis and isolated by elution.
3. Amplification of Gene (PCR):
   The gene of interest is amplified using Polymerase Chain Reaction (PCR) to produce millions of copies for effective cloning.
4. Ligation and Gene Transfer:
   The desired DNA fragment is ligated into a vector and introduced into a host cell by methods such as transformation, electroporation, or gene gun.
5. Expression and Production:
   The host cells expressing the recombinant gene are cultured on a large scale in bioreactors to produce the desired recombinant protein.
6. Downstream Processing:
   The final product is separated, purified, and processed to obtain a market-ready product.

• Biotechnology is based mainly on genetic engineering and bioprocess engineering.
• Genetic engineering involves altering DNA/RNA and introducing desired genes into a host to change its phenotype.
• Bioprocess engineering ensures sterile conditions for large-scale growth of desired microbes or cells to produce products like antibiotics and vaccines.
• Recombinant DNA technology allows transfer of only specific desirable genes, avoiding unwanted genes common in traditional breeding.
• For replication, an alien DNA must be linked to an origin of replication, enabling cloning inside the host.
• Genetic modification involves three steps: identifying the desired gene, introducing it into the host, and maintaining and inheriting it in progeny.

• Cloning vectors are DNA molecules (plasmids or bacteriophages) that can replicate independently inside host cells and help multiply foreign DNA.
• An origin of replication (ori) is essential for replication of the vector and controls the copy number of the inserted DNA.
• Selectable marker genes (e.g., antibiotic resistance genes) help identify and select transformed cells from non-transformants.
• Cloning sites are unique restriction enzyme recognition sites where foreign DNA is inserted into the vector.
• Insertional inactivation of marker genes (e.g., β-galactosidase) helps distinguish recombinants from non-recombinants using colour screening.
• Special vectors like Ti plasmid of Agrobacterium tumifaciens and modified retroviruses are used to transfer genes into plant and animal cells.