Biotechnology and its Applications Class 12 Biology Chapter 10 Notes

Biotechnology and its Applications Class 12 Biology Chapter 10 Notes

Biotechnological Applications in Agriculture

1. Increasing Food Production Options:

• Agro-chemical based agriculture.
• Organic agriculture.
• Genetically engineered crop-based agriculture.

2. The Green Revolution:

• Tripled food supply but insufficient for growing human population.
• Improved crop varieties, better management practices, agrochemicals (fertilizers, pesticides) increased yields.
• Agrochemicals often expensive for developing world farmers.
• Traditional breeding techniques limited.

3. Tissue Culture:

• Regeneration of whole plants from explants (any plant part) in sterile conditions with nutrient media.
• Capacity to generate whole plants from any cell/explant known as totipotency.
• Nutrient medium requires carbon source (e.g., sucrose), inorganic salts, vitamins, amino acids, growth regulators (e.g., auxins, cytokinins).
• Micro-propagation: Producing many plants quickly.
• Somaclones: Genetically identical to parent plant.
• Commercial-scale production of plants like tomato, banana, apple.

4. Recovery of Healthy Plants:

• Meristems (apical and axillary) virus-free.
• Isolation of meristems, in vitro growth yields virus-free plants.
• Successful with banana, sugarcane, potato, etc.

5. Protoplast Isolation:

• Single cell isolation, digestion of cell walls.
• Isolated protoplasts fused to create hybrid protoplasts.
• Somatic hybrids formed via somatic hybridization.
• Example: Pomato (tomato-potato hybrid), not commercially viable.

6. Genetic Modification:

• Genetically Modified Organisms (GMOs) – genes altered by manipulation.
• Genetically Modified plants used to:

1. Tolerate abiotic stresses (cold, drought, salt).
2. Reduce reliance on pesticides (pest-resistant crops).
3. Reduce post-harvest losses.
4. Efficient mineral usage by plants (soil fertility preservation).
5. Enhance nutritional value (e.g., golden rice – Vitamin ‘A’ enriched rice).
6. Supply alternative resources (starches, fuels, pharmaceuticals).

7. Pest Resistance via Genetic Modification:

• Bt toxin from Bacillus thuringiensis (Bt) cloned and expressed in plants.
• Bt Cotton: Toxic protein crystals kill insects (e.g., cotton bollworms) in alkaline gut conditions.
• Specific Bt toxin genes control specific pests (e.g., cryIAc for cotton bollworms).

8. RNA Interference (RNAi) for Pest Resistance:

• Nematode-specific genes introduced into host plant.
• RNAi process silences specific mRNA of nematode.
• Transgenic host plant expressing interfering RNA becomes resistant to nematode infestation.

9. Potential of Biotechnology:

• Alternative path to maximize yield, minimize chemical use, reduce environmental harm.

Biotechnological Applications in Medicine

1. Genetically Engineered Insulin

1. Challenges in Insulin Production:
   • Management of adult-onset diabetes requires regular insulin intake.
   • Shortage of human insulin could lead to the use of insulin from other animals.
   • Questions arise about the effectiveness of animal insulin and potential immune responses.
2. Animal Insulin Limitations:
   • Insulin from animals may not be as effective as human insulin.
   • Animal insulin can trigger immune responses in humans.
3. Bacterial Solution:
   • Imagine using bacteria capable of producing human insulin.
   • This simplifies the process, allowing large-scale insulin production.
4. Oral Administration of Insulin:
   • Consider whether insulin can be administered orally to diabetic individuals.
   • Discuss the challenges and reasons behind the current methods of insulin delivery.
5. Historical Use of Animal Insulin:
   • Previously, insulin was extracted from cattle and pig pancreases.
   • Some patients developed allergies or reactions due to foreign protein.
   • Insulin consists of two polypeptide chains (chain A and chain B) linked by disulfide bridges.
6. Insulin Synthesis in Mammals:
   • In mammals, including humans, insulin is initially synthesized as a pro-hormone.
   • The pro-hormone contains an additional stretch called the C peptide.
   • The C peptide is absent in mature insulin and is removed during maturation.
7. rDNA Techniques for Insulin Production:
   • The main challenge in insulin production using recombinant DNA techniques was achieving the assembly of insulin into a mature form.
   • In 1983, Eli Lilly, an American company, created DNA sequences corresponding to the A and B chains of human insulin.
   • These DNA sequences were introduced into plasmids of E. coli bacteria to produce insulin chains.
   • Chains A and B were produced separately, then extracted and combined by forming disulfide bonds to create human insulin.

2. Gene Therapy

1. Correction of Hereditary Diseases:
   • Gene therapy aims to correct hereditary diseases present from birth.
   • It involves methods to address diagnosed gene defects in children or embryos.
   • Genes are inserted into a person’s cells and tissues to treat the disease.
2. Correction Process:
   • Correction involves delivering a normal gene to replace the non-functional or defective gene.
3. Historical Milestone:
   • The first clinical gene therapy was administered in 1990 to a 4-year-old girl with adenosine deaminase (ADA) deficiency.
   • ADA is crucial for the immune system.
   • The deficiency is caused by the deletion of the ADA gene.
4. Existing Treatments for ADA Deficiency:
   • Some children with ADA deficiency can be treated with bone marrow transplantation.
   • Enzyme replacement therapy involves injecting functional ADA into patients.
   • However, both approaches have limitations and may not provide a complete cure.
5. Gene Therapy for ADA Deficiency:
   • In gene therapy for ADA deficiency, lymphocytes from the patient’s blood are cultured outside the body.
   • A functional ADA cDNA is introduced into these lymphocytes using a retroviral vector.
   • The genetically engineered lymphocytes are then returned to the patient.
   • However, these cells are not immortal, and the patient requires periodic infusion.
6. Potential Permanent Cure:
   • To achieve a permanent cure, the ADA-producing gene isolated from marrow cells can be introduced into cells during early embryonic stages.

Gene therapy offers hope for treating hereditary diseases by addressing the root genetic causes, but it also poses challenges related to the long-term effectiveness and safety of these treatments.

3. Molecular Diagnosis

1. Importance of Early Diagnosis:
   • Early diagnosis and understanding the pathophysiology of a disease are crucial for effective treatment.
   • Conventional diagnostic methods (serum and urine analysis) often lack the ability for early detection.
2. Molecular Techniques for Early Diagnosis:
   • Recombinant DNA technology, Polymerase Chain Reaction (PCR), and Enzyme-Linked Immuno-sorbent Assay (ELISA) enable early diagnosis.
3. PCR for Detecting Low DNA Amounts:
   • PCR can detect very low concentrations of bacteria or viruses before disease symptoms appear.
   • PCR amplifies nucleic acids (DNA or RNA) of the pathogen, making it detectable.
   • It is used to detect diseases like HIV in suspected AIDS patients and mutations in genes in cancer patients.
   • PCR is valuable for identifying various genetic disorders.
4. DNA Hybridization and Autoradiography:
   • Single-stranded DNA or RNA, labeled with a radioactive probe, hybridizes with complementary DNA in cell clones.
   • Detection is done using autoradiography.
   • Mutated genes will not appear on the photographic film because the probe won’t complement the mutated gene.
5. ELISA – Antigen-Antibody Interaction:
   • Enzyme-Linked Immuno-sorbent Assay (ELISA) relies on antigen-antibody interactions.
   • Infection by a pathogen can be detected by:
     • Detecting antigens (proteins, glycoproteins, etc.) associated with the pathogen.
     • Detecting antibodies produced against the pathogen.

Molecular diagnostic techniques like PCR and ELISA are powerful tools for detecting diseases, pathogens, genetic mutations, and other medical conditions at early stages when conventional methods may fail to do so. These techniques have revolutionized healthcare by enabling timely and accurate diagnosis.

Transgenic Animals

• Animals with manipulated DNA to possess and express an extra (foreign) gene are known as transgenic animals. Mice make up the majority (over 95%) of existing transgenic animals, but transgenic rats, rabbits, pigs, sheep, cows, and fish have also been created.
• Benefits and Reasons for Creating Transgenic Animals:
  1. Understanding Normal Physiology and Development:
     1. Transgenic animals can be designed to study gene regulation and their impact on normal body functions and development.
     2. For example, they help in studying complex factors like insulin-like growth factor by introducing genes from other species that affect its formation, providing insights into its biological role.
  2. Study of Diseases:
     1. Many transgenic animals serve as models for human diseases, contributing to our understanding of how genes influence disease development.
     2. These models enable research on new treatments for diseases like cancer, cystic fibrosis, rheumatoid arthritis, and Alzheimer’s.
  3. Biological Products:
     1. Transgenic animals can produce valuable biological products, reducing the cost of manufacturing medicines.
     2. By introducing specific DNA segments or genes, these animals can produce human proteins such as α-1-antitrypsin used to treat emphysema.
     3. Efforts are ongoing for producing treatments for phenylketonuria (PKU) and cystic fibrosis.
     4. In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk, which was nutritionally better for human babies than natural cow’s milk.
  4. Vaccine Safety:
     1. Transgenic mice are being developed to test vaccine safety before human use.
     2. They are used to assess the safety of vaccines, potentially replacing the need for testing on monkeys.
     3. For example, they are employed in testing the safety of the polio vaccine.
  5. Chemical Safety Testing (Toxicity/Safety Testing):
     1. Transgenic animals are used to study the toxicity and safety of chemicals.
     2. These animals carry genes that make them more sensitive to toxic substances than non-transgenic animals.
     3. Exposure to toxic substances helps researchers study their effects more quickly than traditional methods.

Transgenic animals play a crucial role in advancing our understanding of genetics, diseases, and drug development. They offer unique opportunities for research, especially in the fields of medicine and biotechnology.

Ethical Issues in Genetic Modification and Biopiracy

1. Need for Ethical Standards:

• Human manipulation of living organisms requires ethical regulation.
• Ethical standards are needed to assess the morality of activities affecting living organisms.

2. Biological Significance:

• Genetic modification can have unpredictable consequences when organisms are introduced into ecosystems.
• Concerns about ecological impacts and unforeseen consequences.

3. Government Regulation:

• The Indian Government has established organizations like GEAC (Genetic Engineering Approval Committee) to assess GM research validity and safety.
• These organizations make decisions about introducing GM organisms for public services.

4. Patent Issues:

• Problems arise with patents granted for products and technologies based on living organisms used for public services (e.g., food and medicine sources).
• Growing public anger about companies obtaining patents for genetic materials, plants, and biological resources traditionally used by farmers and indigenous people.

5. Basmati Rice Patent Example:

• Basmati rice, with its unique aroma and flavor, has been grown for centuries in India.
• In 1997, an American company received a patent on Basmati rice through the US Patent and Trademark Office.
• The patent extended to functional equivalents, potentially restricting others from selling Basmati rice.

6. Traditional Herbal Medicines Patents:

• Attempts to patent uses, products, and processes based on Indian traditional herbal medicines like turmeric and neem.
• Urgent vigilance needed to counter such patent applications.

7. Biopiracy:

• Biopiracy refers to the unauthorized use of bio-resources by multinational companies and organizations without proper authorization from the concerned countries and people.
• Typically occurs in regions rich in biodiversity and traditional knowledge.

8. Compensation and Benefit Sharing:

• Inadequate compensation and benefit sharing between developed and developing countries regarding traditional knowledge and bio-resources.
• Growing realization of injustice in these arrangements.

9. Legal Measures:

• Some nations are developing laws to prevent unauthorized exploitation of their bio-resources and traditional knowledge.
• India has recently amended its Patents Bill to address these issues, including patent terms, emergency provisions, and research and development initiatives.

Ethical considerations, along with legal regulations, are essential to address the complex challenges posed by genetic modification, biopiracy, and the exploitation of traditional knowledge and bio-resources. Such efforts aim to ensure fair and just treatment of these valuable resources and their benefits for all.