NEET Biology Class 12 Biotechnology And Its Applications Notes

Biotechnology And Its Applications

Biotechnology has a wide range applications such as biopharmaceuticals, therapeutics, diagnostics, genetically modified crops for agriculture, processed food, bioremediation, waste treatment, and energy production.

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Biotechnology has 3 critical research areas:

1. Providing the best catalyst in the form of an improved organism usually a microbe or pure enzyme.
2. Creating optimal conditions through engineering for a catalyst to act.
3. Downstream processing technologies to purify the protein/organic compound

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Applications In Agriculture

Applications In Agriculture

Options for increasing food production:

1. Agro-chemical based agriculture.
2. Organic agriculture.
3. Genetically engineered crop-based agriculture.

Genetically Modified Organisms (GMO) or transgenic organisms are the plants, bacteria, fungi and animals whose genes are altered by manipulation.

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Advantages of genetic modification in plants:

• It makes crops more tolerant to abiotic stresses (cold, drought, salt, heat, etc.).
• Pest-resistant crops reduce the use of chemical pesticides.
• It helps to reduce post-harvest losses.
• It increases the efficiency of mineral usage by plants (it prevents early exhaustion of fertility of soil).
• It enhances the nutritional value of food. example, Vitamin A-enriched rice.
• To create tailor-made plants to supply alternative resources (starches, fuels, pharmaceuticals, etc.) to industries.

Pest Resistant Plants:

• They act as bio-pesticides.
• It reduces the need for insecticides.
• For example, Bt cotton, Bt corn, rice, tomato, potato, soybean, etc.

Bt Cotton:

Some strains of Bacillus thuringiensis have proteins that kill insects like coleopterans (beetles) lepidopterans (tobacco budworm, armyworm), and dipterans (flies, mosquitoes).

• B. thuringiensis forms a toxic insecticidal protein (Bt toxin) crystal during a particular phase of their growth. It does not kill the Bacillus as it exists as inactive protoxins.
• When an insect ingests the toxin, it becomes active due to the alkaline pH of the gut which solubilizes the crystals.
• The toxin binds to the surface of mid-gut epithelial cells and creates pores. It causes cell swelling lysis and death of the insect.
• Bt toxin genes were isolated from B. thuringiensis and incorporated into crop plants such as cotton.
• Most Bt toxins are insect-group-specific. The toxin is
• Coded by a gene named cry. for example, proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms of cryIAb control corn borer.

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Nematode resistance in tobacco plants:

• A nematode Meloidogyne incognitia infects the roots of tobacco plants causing a reduction in yield.
• It can be prevented by RNA interference (RNAi) strategy.
• RNAi is a method of cellular defense in all eukaryotic organisms. It prevents the translation of a specific mRNA (silencing) due to a complementary dsRNA molecule.
• The source of this complementary RNA is from infection by RNA viruses or mobile genetic elements (transposons) that replicate via an RNA intermediate.
• Using Agrobacterium vectors, nematode-specific genes (DNA) are introduced into the host plant. It produces both sense and anti-sense RNA in host cells.
• These RNAs are complementary. So they form double-stranded (ds) RNA.
• It initiates RNAi and silences the specific mRNA of the nematode. Thus the parasite cannot survive in a transgenic host expressing specific interfering RNA.

Applications In Medicine

Medicine:

• The recombinant DNA technology helps for the mass production of safe and more effective therapeutic drugs.
• The products from non-human sources induce unwanted immunological responses. However recombinant therapeutics do not have such problems.
• At present, about 30 recombinant therapeutics have been approved. Of these, 12 are being marketed in India.

1. Genetically Engineered Insulin:

• Insulin is used to manage adult-onset diabetes.
• Insulin from the pancreas of animals (cattle and pigs) causes allergies or other types of reactions to the foreign protein.
• Now, it is possible to produce human insulin using bacteria.
• Insulin consists of two short polypeptide chains (chain A and chain B) that are linked by disulfide bridges.
• In mammals, insulin is synthesized as a pro-hormone (pro-insulin). It needs processing to become a mature and functional hormone.
• The pro-hormone contains an extra stretch called the C peptide. This is removed during maturation into insulin.
• In 1983, Eli Lilly (an American company) prepared two
• DNA sequences corresponding to A and B chains of human insulin and introduced in plasmids of E. coli to produce insulin chains.
• Chains A and B were combined by creating disulfide bonds to form human insulin

2. Gene Therapy:

• It is a method to correct a gene defect in a child/embryo.
• Here, genes are inserted into a person’s cells and tissues to treat a hereditary disease. It compensates for the nonfunctional gene.
• The first clinical gene therapy (1990) was given to a 4-year-old girl with adenosine deaminase (ADA) deficiency.
• This disorder is caused due to the deletion of the gene for adenosine deaminase (an enzyme crucial for the immune system to function).
• This can be cured by bone marrow transplantation or by enzyme replacement therapy (injection of ADA). But these are not completely curative.
• In gene therapy, lymphocytes from the patient’s blood are grown in a culture.
• Then, a functional ADA cDNA (using a retroviral vector) is introduced into lymphocytes.
• Then, they are returned to the patient. This should be periodically repeated as these cells are not immortal.
• If the ADA gene (from marrow cells) is introduced into cells at early embryonic stages, it could be a permanent cure.

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3. Molecular Diagnosis:

• Early diagnosis of diseases is not possible using conventional methods (serum and urine analysis).
• It is possible by techniques such as Recombinant DNA technology,

PCR & ELISA. PCR (Polymerase Chain Reaction):

• The presence of a pathogen is normally suspected only based on symptoms.
• By this time, the concentration of pathogens is already very high in the body.
• However, very low concentrations of bacteria or viruses can be detected by amplification of their nucleic acid by PCR.

Uses of PCR:

• To detect HIV in suspected AIDS patients.
• To detect gene mutations in suspected cancer patients.
• To identify many other genetic disorders.
• A single-stranded DNA or RNA, tagged with a radioactive molecule (probe) is hybridized to its complementary DNA in a clone of cells followed by detection using autoradiography.
• The clone having a mutated gene will not appear on the photographic film, because the probe will not have complementarity with the mutated gene.

ELISA (Enzyme-Linked Immuno-Sorbent Assay):

• It is based on the principle of antigen-antibody interaction.
• Infection by pathogens can be detected by the presence of antigens (proteins, glycoproteins, etc.) or by detecting the antibodies synthesized against the pathogen.

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Transgenic Animals

These are the animals whose genome has been altered by the introduction of an extra (foreign) gene by manipulation.

• Examples are transgenic rats, rabbits, pigs, sheep, cows, and fish.
• Over 95% of the transgenic animals are mice.

Benefits of transgenic animals:

To study the regulation of genes and their action on normal Physiology & development:

• For example, Study of complex factors such as insulin-like growth factor. Genes (from other species) that alter the formation of this factor are introduced and the biological effects are studied.
• This gives information about the biological role of the factor in the body.

To Study the contribution of genes in the development of a disease and thereby new treatments:

For example, transgenic models for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis & Alzheimer’s.

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Biological products:

• Some medicines contain expensive biological products. Transgenic animals are used to produce useful biological products by introducing genes that code for a particular product.
• For example, human protein (α-1-antitrypsin) is used to treat emphysema, products for the treatment of phenylketonuria (PKU) and cystic fibrosis, etc.
• In 1997, Rosie (the first transgenic cow) produced human protein-enriched milk (2.4 gm per liter).
• It contains the human α-lactalbumin and is a nutritionally more balanced product for human babies than natural cow milk.

Vaccine safety testing:

• Transgenic mice are used to test the safety of the polio vaccine.
• If it is reliable, they can replace the use of monkeys to test the safety of vaccines.

Chemical safety testing (toxicity testing):

• Some transgenic animals carry genes that make them more sensitive to toxic substances than non-transgenic animals.
• They are exposed to the toxic substances and the effects studied. It gives immediate results.
• The problem of unpredictable results: Genetic modification may cause unpredictable results.

Ethical Issues

The problem of unpredictable results: Genetic modification may cause unpredictable results.

• Indian Government has set up organizations like GEAC (Genetic
• Engineering Approval Committee) to make decisions about the validity of GM research and the safety of GM organisms for public services.

Problems of patent:

• Certain companies have patents for products and technologies that make use of genetic materials, plants, etc.
• That has been identified, developed, and used by farmers and indigenous people of a country. Examples, are Basmati rice, and herbal medicines (turmeric, neem, etc).

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Basmati rice:

• Basmati rice has a unique aroma & flavor. India has 27 varieties of Basmati.
• In 1997, an American company got patent rights on Basmati rice through the US Patent and
• Trademark Office. This allowed the company to sell a ‘new’ variety of Basmati. This was derived from
• Indian farmer’s varieties. Indian Basmati was crossed with semi-dwarf varieties and claimed as a novelty.
• Other people selling Basmati rice could be restricted by patent.

Biopiracy:

It is the use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned.

• Most of the industrialized nations are poor in biodiversity and traditional knowledge.
• The developing and underdeveloped world has rich biodiversity and traditional knowledge related to bio-resources.
• It has to develop laws to prevent unauthorized exploitation of bio-resources and traditional knowledge.
• Indian Parliament has cleared the second amendment of the
• Indian Patents Bill that has considered patent terms emergency provisions and research and development initiatives.