Biotechnology Principles and Processes Class 12 Notes- Super Guide

Biotechnology Principles and Processes Class 12 Notes

Biotechnology, according to the European Federation of Biotechnology (EFB), is the application of natural science and organisms, cells, parts thereof, and molecular analogs to create products and services. Karl Ereky created the word “biotechnology” in 1919.

Biotechnology principles are founded on the concepts of the following techniques:
(i) Genetic engineering is the process of changing the chemistry of genetic material (DNA/ RNA) and introducing it into other species to modify the phenotypic of the host organism.
(ii) Adequate sterile condition maintenance to support large-scale development of just the necessary microbes/eukaryotic cells for the production of biotechnological products such as antibiotics & enzymes and vaccines, etc.

The techniques involved in Genetic engineering approaches include the following steps:
(i) Making recombinant DNA by fusing desired genes that are obtained from fragmented DNA from the donor.
ii) Genetic transfer into the vector DNA. Victor DNA carries the information to be passed from the donor to the recipient’s DNA.
(iii) DNA maintenance in the host and gene cloning.

The fundamental processes in genetic engineering are as follows:
(i) Finding DNA that has good genes.
(ii) Instilling the recognized DNA into the host.
(iii) Preservation of the inserted DNA in the host and Transmission of the DNA to its progeny

Development of the First Artificial Recombinant DNA
(i) It was accomplished by fusing an antibiotic resistance gene with a natural Salmonella typhimurium plasmid (autonomously replicating circular extrachromosomal DNA).
(ii) This was done in 1972 by Stanley Cohen and Herbert Boyer.
(iii) They extracted the antibiotic resistance gene by removing a portion of DNA.

What is Recombinant DNA technology that is mentioned in Biotechnology principles and processes class 12 notes?

Genetic engineering

It is another term for recombinant DNA technology. It is the process of connecting two separate species’ DNA molecules. This is referred to as recombinant DNA.

The following steps are included in the Recombinant DNA technology processes: (i) DNA isolation
(ii)The use of restriction endonucleases to fragment DNA
(iii)The requested DNA segment is ligated into the vector.
(iv)Transferring recombinant DNA into the host Culture of transformed cells in a nutritional medium
(v) The desired product is extracted.

Tools to perform genetic engineering Recombinant DNA are (i) Restriction enzymes (ii) Polymerase enzymes
(iii) Ligases (iv) Vectors (v) a healthy host organism

Recombinant DNA Processes

biotechnology principles and processes class 12 notes

Stanley Cohen and Herbert Boyer extracted the antibiotic resistance gene in 1972 by removing a fragment of DNA from a Salmonella typhimurium plasmid (autonomously reproducing circular extra-chromosomal DNA). The discovery of so-called molecular scissors–restriction enzymes–made it feasible to cut DNA at specified spots. The plasmid DNA was then joined to the snipped fragment of DNA. This plasmid DNA serve as vectors for the DNA connected to them.

A plasmid can be used as a vector to introduce foreign DNA into the host organism. The enzyme ligase, which acts on cut DNA molecules and connects their ends, makes it feasible to attach antibiotic-resistant genes to plasmid vectors. This results in a novel combination of Recombinant DNA is self-replicating DNA that was created in vitro.

Restriction Enzymes

Restriction enzymes are members of the nuclease enzyme family.
There are two kinds of nucleases:
Exonucleases:- They take nucleotides out of the ends.
Endonucleases are enzymes that cleave DNA at precise locations.

(a) Each restriction endonuclease recognizes a different palindromic nucleotide sequence in DNA.
(b) A palindrome in DNA is a sequence of base pairs that reads the same on both strands when the reading orientation is maintained constant. For example, 5′, GAATTC — 3′, CTTAAG — 5′

Isolation Process

DNA Fragment Separation and Isolation is a very tricky business and needs to be done with precision.
(i)The cutting of DNA by restriction endonucleases produces DNA fragments.
(ii) Gel electrophoresis is a method for separating DNA fragments based on their size.
DNA fragments are negatively-charged molecules

(iii) They can be separated by causing them to travel towards the anode through a medium/matrix under an electric field.
(iv) Agarose, a natural polymer produced from seaweeds, is the most often utilized medium.
(v) The agarose gel’s sieving function separates (resolves) the DNA fragments based on their size. The smaller the fragment size, the greater the distance travelled.

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Only after staining the DNA with ethidium bromide and then exposing it to light can the separated DNA fragments be seen.


a. The sequence from which replication begins, and any fragment of DNA connected to this sequence, may be forced to replicate within the host cells. This segment is in charge of regulating the copy number of the connected DNA.

b. Selectable markers aid in the identification and elimination of non-transformants while selectively allowing the development of transformants. Transformation is the process of inserting a fragment of DNA into a host bacteria. In general, genes encoding antibiotic resistance, such as ampicillin, chloramphenicol, tetracycline, or kanamycin, are thought to be helpful selection markers for E. coli.

c. Cloning sites– To connect the foreign DNA, the vector must include a single recognition site for the generally employed restriction enzymes, as the presence of more than one undesirable Recognition site inside the vector will yield many fragments, complicating gene cloning. The foreign DNA is ligated at a restriction point found in one of the two antibiotic resistance genes.

So what are the Cloning vectors?

Cloning vectors are nothing but the DNA molecules that can carry a foreign DNA segment into the host cell.
(i) The vectors used in recombinant DNA technology can be: (a) Plasmids Autonomously replicating circular extra-chromosomal DNA.
(b) Bacteriophages Viruses infecting bacteria.
(c) Cosmids Hybrid vectors derived from plasmids which contain cos site of X phage.

(ii) Copy number can be defined as the number of copies of vectors present in a cell.
(iii) Bacteriophages have a high number per cell, so their copy number is also high in the genome.
(iv) Plasmids have only one or two copies per cell.
(v) Copy number can vary from 1-100 or more than 100 copies per cell.
(vi) If an alien piece of DNA is linked with bacteriophage or plasmid DNA, its number can be multiplied equal to the copy number of the plasmid or bacteriophage.
(vii) Features Required to Facilitate Cloning into Vector. (a) Origin of replication (Ori)     (b) Selectable marker
(c) Cloning sites                             (d) Vectors for cloning genes in plants and animals.

Because of the inclusion of foreign DNA, the recombinant plasmids will lose their tetracycline resistance. It may, however, be distinguished from non-recombinant ones by plating the transformants on ampicillin-containing media.
– Transformants grown on ampicillin-containing media are subsequently transferred to the tetracycline-containing medium.
– The recombinants will grow in ampicillin-containing media but not in tetracycline-containing medium.
Non-recombinant bacteria will grow in a medium containing both antibiotics.
In this case, one antibiotic resistance gene aids in the selection of transformants.

Capable Host Ready for Recombination

1) A chemical treatment with calcium ions helps to increase the efficiency of recipient cells to take up the rDNA plasmids (via cell wall pores).
2) rDNA are also transformed into host cells by incubating both on ice, then briefly placing them at 42oC (Heat Shock), and then returning to the ice. This allows the bacteria to consume the recombinant DNA.

3) in the Microinjection method, Using a glass micropipette, rDNA is directly inserted inside the nucleus of cells. 
4) Biolistics / Gene gun method, which is devised to insert rDNA into plant cells primarily through the use of a Gene / Particle gun. In this method, microscopic gold/tungsten particles are coated with the DNA of interest and sprayed onto cells
5) The final method employs “Disarmed Pathogen” Vectors (Agrobacterium tumefaciens), which, once infected, transfer the recombinant DNA into the host.


Biotechnology principles and processes class 12 notes is an interesting as well as an important lesson for the class 12 syllabus. Biotechnology is a subject offered in higher education. So, if any student is willing to take up this subject in the graduation, he or she must adhere to the biotechnology principles and processes class 12 notes.

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