Biotechnology and its Applications Class 12 Notes Biology Chapter 12


  • The use of biology to develop technologies and products for the welfare of human beings is known as biotechnology.
  • The applications of biotechnology include therapeutics, diagnostics, genetically modified crops for agriculture, processed food, bioremediation, waste treatment and energy production.


  • The use of biotechnology in agriculture is known as green biotechnology. The organisms formed after manipulation of genes is known as Genetically Modified Organisms such as crops, animals, plants, fungi, bacteria etc.
  • Genetic modifications which have been introduced has :
    • made crops more tolerant to abiotic stresses [cold, drought, salt and heat].
    • reduced reliance on chemical pesticide (pest-resistant crop).
    • helped to reduce post harvest losses.
    • increased efficiency of mineral usage by plant to prevent early exhaustion of fertility of soil.
    • enhanced nutritional value of food, e.g., vitamin A enriched golden rice.
  • Genetically modified crops or transgenic crops are prepared by transferring genes from one plant to other. The plant in which foreign genes are introduced are known as transgenic crops. These manipulations are done to introduce traits such as pest resistance, insect resistance, weed resistance etc.
  • Bt cotton is the first genetically modified crop of the country. It is a pest resistant plant which resist attack of Lepidopterans insects. The plant Bt toxin gene cause death of insect larvae by causing cell lysis and swelling of epithelium of midgut.
  • Bt toxin is biologically produced by bacterium called Bacillus thuringiensis (Bt).
  • Bt toxin is coded by gene called CRY genes. These Bt toxin genes are isolated from bacteria and incorporated into several crop plants like cotton which has these lepidopteran insects as pests.
  • B. thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein.
  • The proteins encoded by the genes crylAc and cryIIAb control the cotton bollworms that of crylAb control corn borer.
  • Pest resistant plant is a variety that is less susceptible to pest damage when compared with other crops.
  • Prevention of nematode Meloidegyne incognitia parasitism on roots of tobacco plants is done by (RNAi) RNA interference technology.
  • RNAi is a method of cellular defense in all eukaryotes.
  • RNAi is silencing ofmRNA due to complementary double stranded RNA that prevents translation of mRNA [silencing]. It is used for nematode control in tobacco plant.
  • Using Agrobacterium as a vector, nematode specific DNA is introduced into host plant which produces dsRNA. They initiate RNAi and silence specific mRNA when go inside nematode. Thus, parasite could not survive in transgenic host expressing specific dsRNA acting as RNAi.
  • Tomato plant Flavr savr is genetically modified which produces much less cell wall degrading enzyme, polygalactouronase, responsible for fruit ripening. Therefore, the fruit of these plants have much larger and favourable shelf life.
  • Transgenic/genetically engineering plants can also:
    • produce pharmaceutically important compounds such as human insulin, interferons, hormones, etc.
    • synthesise antibody and vaccines in fruits.
    • bear flowers with new colours and long life for better ornamental purposes.
  • Insulin was extracted from pancreas of cattle, pigs in limited quantity. Genetically engineered insulin helps in the management of diabetes after regular time intervals.
  • Gene therapy is alteration of specific genes to modify the patient’s genotype for the treatment of hereditary diseases like SCID, haemophilia and phenylketonuria.
  • A gene cannot be directly inserted into a persons cell. It must be delivered to the cell using a carrier or vector. The vectors most commonly used in gene therapy are viruses.
  • The first clinical gene therapy was given to 4 years old in 1990 with ADA deficiency.
  • Severely combined immunodeficiency disease (SCID) patient has a defective gene for enzyme adenosine deaminase (ADA). Patient do not have T lymphocyte and don’t mount immune response against pathogens. So to correct SCID with the help of gene therapy:
    • A WBC is extracted from bone marrow of sufferer and a good copy of human gene encoding ADA is introduced by retrovirus as vector.
    • This leads to WBC with a good copy of gene, in addition to existing faulty copy.
    • The treated cells are reinjected to patient’s bone marrow and cells play normal role in immune system.
  • Genetics as well as infectious diseases can be diagnosed using probe consisting of short segment of dsDNA attached to fluorescent marker. These are used for identification of food poisoning (Salmonella), pus forming (Staphylococcus), hepatitis virus, HIV of AIDS using ELISA.
  • ELISA is a laboratory test, which can quickly determine antigen or antibody levels in blood or other fluids.
  • A single stranded DNA/RNA attached with radioactive molecule is called molecular probe. Molecular probes are used for detection of gene by complementary hybridising in cloned cell, followed by autoradiography.
  • Hirudin is a protein that stops blood clotting. The gene encoding hirudin was chemically synthesised and then transferred into Brassica napus, where hirudin accumulates in seeds. The hirudin is purified and used as medicine.


  • Animals that have their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic animals. For example: rats, rabbits, pigs, sheep etc.
  • Transgenic sheep produce clotting factor for haemophilics.
  • Transgenic goat produce protein to dissolve clot, cure for coronary thrombosis.
  • Transgenic cattle, sheep and fish grow most quickly and produce more meat.
  • Ethical issues refer to the situation in which we need to select the best amongst the various alternatives. Same is the case with biotechnology as well.
  • For reduction of ethical issues Indian government has set up organisation GEAC [Genetic engineering approval committees], that make decision regarding validity of GM research and safety of introducing GMO in ecosystem.
  • Biopiracy is unethical and illegal use of biodiversity resource of person concerned without any compensation.
  • Biopiracy of African super-sweet berries: Pentadiplandra brazzein is a plant found in the west of South Africa. It is a vital source of protein known as brazzein.
  • Patent laws are desirable not only to solve ethical issues related to GMO and introduction of new variety but also to prevent and flourish biodiversity and rich bioresource heritage of lndia.

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