Key Points

Biotechnology uses genetically modified microbes, fungi, plants, and animals for industrial-scale production of biopharmaceuticals, GM crops, diagnostics, and therapeutics to improve human life.

Micropropagation is a tissue culture technique for producing thousands of genetically identical plants (somaclones) in a short time. This process is based on the principle of totipotency, where any plant cell can regenerate into a whole plant.

Virus-free plants can be recovered from diseased ones by culturing the meristem (apical and axillary). The meristem is typically free of viruses, and this technique has been successful for plants like banana, sugarcane, and potato.

GM crops are plants whose genes have been altered for beneficial traits. These include tolerance to abiotic stresses (cold, drought), reduced reliance on chemical pesticides, and enhanced nutritional value, like Vitamin 'A' enriched 'golden rice'.

Bt toxin is an insecticidal protein produced by the bacterium Bacillus thuringiensis (Bt). The gene for this toxin is introduced into crop plants like cotton and corn, making them resistant to pests like bollworms and corn borers.

The Bt toxin is an inactive protoxin that becomes active in the alkaline pH of an insect's gut. The active toxin binds to the midgut epithelial cells, creating pores that cause cell swelling and lysis, eventually killing the insect.

The genes encoding Bt toxin proteins are named 'cry'. Different cry genes are specific to different pests; for example, genes cryIAc and cryIIAb control cotton bollworms, while cryIAb controls corn borer.

RNAi is a natural cellular defense mechanism in all eukaryotes. It involves silencing a specific mRNA by a complementary double-stranded RNA (dsRNA) molecule, which binds to the mRNA and prevents its translation.

To protect tobacco plants from the nematode Meloidegyne incognitia, nematode-specific genes are introduced into the plant to produce dsRNA. This initiates RNAi, silencing the nematode's vital mRNA and preventing infestation.

Human insulin for diabetes is produced using recombinant DNA technology. In 1983, Eli Lilly synthesized the A and B chains of human insulin separately in E. coli and then combined them by creating disulfide bonds.

In humans, insulin is synthesized as a pro-hormone containing an extra C peptide. This C peptide is removed during maturation. Recombinant insulin production bypasses this step by producing the A and B chains directly.

Gene therapy is a collection of methods that allows for the correction of a gene defect in a child or embryo. It involves inserting a normal gene into cells to compensate for a non-functional gene and treat a disease.

The first clinical gene therapy was for adenosine deaminase (ADA) deficiency. It involved introducing a functional ADA cDNA into the patient's lymphocytes using a retroviral vector to restore immune function.

Early disease diagnosis is possible using techniques like PCR and ELISA. PCR (Polymerase Chain Reaction) amplifies nucleic acids to detect pathogens like HIV, while ELISA (Enzyme-Linked Immunosorbent Assay) works on the principle of antigen-antibody interaction.

Animals with manipulated DNA to express a foreign gene are called transgenic animals. They are used to study diseases, test vaccine safety, and produce biological products, such as the cow 'Rosie' which produced human protein-enriched milk.

Genetic modification raises ethical questions regarding its impact on ecosystems and morality. In India, the Genetic Engineering Approval Committee (GEAC) makes decisions on the validity and safety of GM research and products.

Biopiracy is the term for the use of bio-resources by organizations without proper authorization or payment to the concerned countries or communities. This includes patenting products based on traditional knowledge, such as Basmati rice and neem.