Q1. What are genetically modified organisms?
Ans: Genetically modified organisms (GMOs) are plants, bacteria, fungi and animals whose genes have been altered by manipulation.
Q2. What is biopiracy? Explain it with reference to Basmati rice.
Ans: Biopiracy is defined as the use of bioresources by multinational companies and other organisations, without proper authorisation from the countries and concerned people, without compensatory payment.
Basmati rice is an indigenous crop of India but it was patented by an American company RiceTech Inc in 1997. This is an example of biopiracy.
Q3. Write a note on gene therapy?
Gene therapy is a collection of methods that allows correction of gene defects, diagnosed in a child or embryo.
By insertion of normal genes, the defective mutant allele of the genes are replaced and non-functional gene is compensated.
For the first time in 1990, M. Blease and W. F. Andresco of National Institute of Health, attempted gene therapy on a 4-year-old girl with adenosine deaminase (ADA) deficiency.
Lymphocytes are isolated from the blood or bone marrow of the patient and grown in a culture outside the body.
A normal ADA gene is isolated from normal cells.
This normal functional ADA gene is then introduced into the cultured lymphocytes, which are subsequently returned to the patient.
These cells have a limited life, so the patient requires repeated infusion of such genetically engineered lymphocytes.
Gene therapy is used to prevent cystic fibrosis diseases.
Q4. What are transgenic animals? List their benefits.
Animals whose DNA is manipulated to possess and express an extra (foreign) gene are known as transgenic animals.
Benefits of transgenic animals:
Study of normal physiology and development.
Study of diseases like a cancer cystic fibrosis, rheumatoid arthritis and Alzheimer's disease.
To obtain biologically improved products e.g., Alpha-1-antitrypsin used to treat emphysema, Rosie, the first transgenic cow to produce protein enrich milk.
To ensure vaccine safety.
For chemical safety testing - mice are the most commonly used organisms for transgenic experiments.
Q5. List out the uses of genetically modified plants.
Increased tolerance against abiotic stresses (cold, drought, salt, heat).
Reduced reliance on chemical pesticides (pest-resistant crops).
Helped to reduce post-harvest losses.
Increased efficiency of minerals used by plants (this prevents early exhaustion of fertility of soil).
Enhanced nutritional value of food, e.g., vitamin 'A' enriched rice (golden rice).
Creation of tailor-made plants to supply alternative resources such as starches, fuels and pharmaceuticals to industries.
Q6. One of the applications of biotechnology is to get pest resistant plants. Justify the statement with reference to Bt. Cotton.
Some strains of Bacillus thuringiensis produce proteins that kill some insects like lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).
B. thuringiensis forms protein crystals which contain a toxic insecticidal protein.
Bt toxins are initially inactive protoxins but after ingestion by the insect their inactive toxin becomes active due to the alkaline pH of the gut, which solublises the crystals.
The activated toxin binds to the surface of midgut epithelial cells thus creating pores which causes cell swelling and lysis, further leading to death of the insects.
Specific Bt toxin genes obtained from Bacillus thuringiensis are used in several crop plants like cotton.
The toxin is coded by a gene called cry which is of various types. For example, proteins encoded by the genes cryIAc and cryIIAb control the cotton bollworms and that of cryIAb control corn borer.