Biotechnology and its Applications

Transcription

1 Chapter 12 Biotechnology and its Applications IMPORTANT TERMS 1. Biotechnology: It is a branch of science that deals with industrial scale production of biopharmaceuticals and biological using genetically modified microbes and animals. 2. Genetically Modified Organisms GMOs: Plants,bacteria, fungi and animals whose genes have been altered by manipulation are called genetically modified organisms (GMOs). 3. RNA interference: A novel strategy adopted to prevent infestation of nematode Meloidegyne incognitia in roots of tobacco plants by a process called RNA interference. 4. Gene therapy: It is a collection of methods that allows correction of a genetic defect that has been diagnosed in a child/embryo. 5. ADA: Adenosine Deaminase is a enzyme which is crucial for the immune system to function. 6. Transgenic animals: Animals that have had their DNA manipulated to possess and express an extra gene are known as transgenic animals. 7. Biopiracy: It is a term use to refer to the use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned without compensatory payment. 8. Bt: Bacillus thuringiensis. 9. GEAC: Genetic Engineering Approval Committee 10. PCR: Polymerase Chain Reaction 11. ELISA: Enzyme Linked Immuno Sorbent Assay IDENTICAL TERMS: cryiac/ cryiiab cryiac/ cryiab

2 POINTS TO REMEMBER 1. Biotechnology The application of biotechnology include (i) Therapeutics (iii) Genetically modified crops for agriculture (ii) Diagnostics (iv) Processed food (v) Waste treatment The three critical research areas of biotechnology are : (i) Providing the best catalyst in the form of improved organism, usually in the form of a microbe or pure enzyme. (ii) Creating optimal conditions through engineering for a catalyst to function and (iii) Downstream processing technologies to purify the protein/organic compound. 2. Application of biotechnology in Agriculture The three options fro increased food production are : i. Agrochemical based agriculture. ii. Organic agriculture and iii. Genetically engineered crop-based agriculture. The Green Revolution succeeded in increasing the yield of crops mainly due to iv. Use of improved varieties of crops and ii. Use of agrochemicals (fertilizers and pesticides). Further increases in the yield with the existing varieties of crops are not possible using conevtional methods of breeding. Agrochemicals cause pollution of soil and water and too expensive for the framers. The use of genetically modified plants has been useful in the following ways: (i) Genetic modification has made the crops more tolerant to abiotic stresses like cold, heat, drought, salinity, etc. (ii) It has reduced the dependence of crops on chemical pesticides as they are made pest-resistant. (iii) Post harvest losses are much reduced. (iv) As the plants increased efficiency of mineral usage plants, the early exhaustion of fertility of soil is prevented. (v) (vi) Food produced from GM (Genetically Modified) crops has enhanced nutritional value. Genetic modification has been used to create tailor-made plants to supply resources to industries such as starch, fuel, pharmaceuticals, etc. 3. Production of Pest Resistant Plants (a) Bt Cotton. - The soil bacterium Bacillus thuringiensis produces crystal proteins called Cry proteins, that are toxic to larvae of insects like Tobacco budworm, armyworm, beetles and mosquitoes.

3 - The Cry proteins exist as inactive protoxins and get converted into active toxin when ingested by the insect, as the alkaline ph of gut solubilises the crystals. - The activated toxin binds to the surface of epithelial cells of midgut and creates pores. - This causes swelling and lysis of cells leading to the death of the insect (Larva). - The genes (cry genes) encoding this protein are isolated from the bacterium and incorporated into several crop plants like cotton, tomato, corn, rice, soybean, etc. - The proteins encoded by the following cry genes control the pest given against them. = cry I Ac and cry II Ab control cotton bollworms. = cry I Ab controls corn borer. = cry III Ab controls colarado potato beetle. = cry III Bb controls corn rootworm. (b) Protection against Nematodes. - A nematode Meloidogyne incognita infects tobacco plants and reduces their yield. - The specific genes ( in the form of c DNA) from the parasite are introduced into the plant using Agrobacterium as the vector. - The genes are introduced in such a way that both sense/coding RNA and antisense RNA (Complimentary to the sense/ coding RNA) are produced. - Since these two RNAs are complementary, they from a double stranded RNA (ds RNA) - This neutralizes the specific RNA of the nematode, by a process called RNA interference. As result the parasite cannot line in the transgenic host and the transgenic plant protected from the pest. 4. Application of biotechnology in medicine The rdna technology has been used in the production of safe and more effective therapeutic drugs. The recombinant therapeutics do not induced unwanted immunological response, that are commonly observed with similar products isolated from non human resources. At present about thirty recombinant therapeutics have been approved fro human use, of which twelve are being marketed in India also.

4 (i) Genetically engineered insulin (himulin). - Human insulin consists of two short polypeptide chains : chain a and chain B, linked by disulphide bridges. - Insulin is secreted as prohormone which has to be processed before it becomes a mature and functional hormone. - the prohormone contains another polypeptide called C- peptide, which is removed during maturation. - In 1983, Eli lilly, an American company, prepared two DNA sequences coding for chains A and B of human insulin and introduced them into plasmids of Escherichia coli to produce insulin. - The two chains produced were extracted and combined by creating disulfide bridges. (ii) Gene therapy - In this method, genes are inserted into cells and tissues of an individual to correct certain hereditary diseases. - It involves the delivery of a normal gene into the individual or embryo to replace the defective mutant allele of the gene. - Viruses which attack the host and introduce their genetic material into host are all used as vectors. - The first clinical gene therapy was given in 1990 to a four year old girl with adenosine deaminase (ADA) deficiency. - ADA deficiency can be cured by bone marrow transplantation in some children but it is not completely curative. - For gene therapy, lymphocytes were grown in a cultural and functional ADA. cdna is then introduced into these lymphocytes. - These lymphocytes are then transferred into the body of the patient ; the patient requires periodically infusion of such genetically engineered lymphocytes. - If a functional gene is introduced into the bone marrow cells at early embryonic stage, it would be permanent cure. (iii) Molecular diagnosis.

5 - Recombinant DNA molecules and techniques like PCR (Polymerase Chain Reaction) are used fro early diagnosis of disorders. - Cloned gene when expressed to produce recombinant proteins, help developing sensitive diagnostic techniques like ELISA. - The cloned genes are also used as probes to detect the presence of complimentary DNA strand. - A probe is a piece of single stranded DNA, that is tagged with a radioactive molecule and it is used ti find its complimentary DNA by hybridization. - It is followed by detection of radioactivity by autoradiography. - Presence of a normal or mutant gene can be detected using such a method. - PCR is used to detect HIV and to detect mutations in gene. 5. Transgenic Animals. Transgenic animals are those animals that have had their DNA manipulated to possesa and express a foreign gene. Transgenic animals are used in the following ways : (i) Transgenic animals can be specifically deigned to allow the study of how genes are regulated and how they affect the normal functions of the body and its developments e.g. Information is obtained about the biological role of insulin like growth factor. (ii) The transgenic animals are designed to increase our understanding of how genes contribute to the development of diseases ; they are made to serve as model for human diseases. (iii) Transgenic animals that produce useful biological compounds can be created by introducing a portion of DNA that codes for that product from organism (s) e.g. alpha 1, antitrypsin, a human protein used to treat emphysema. The first transgenic cow, Rosie, produced the human proteinenriched milk (2.4g/ltr); it also contained human alpha lactalbumin, a more nutritionally balance product for human babies. (iv) (v) 6. Ethical Issues. Transgenic mice are being developed fro use in testing the safety of vaccines. (e.g polio vaccine). Transgenic animals with more sensitivity to toxic substances are being developed to test the toxicity of drugs. Genetic modification of organism can hane unpredictable/ undesirable effects when such organisms are introduced into the ecosystem. The modification and use of such organism fro public service has also resulted in problems with the granting of patents. Hence, the Indian Government has set up organization which are authorized to make decisions regarding the validity of genetic modification and the safety of introducing genetically modified organisms fro public services. One such organization is the Genetic Engineering approval committee (GEAC). 7. Biopiracy

6 The industrialized/ developed nations are rich financially, bur poor in biodiversity and traditional knowledge, while the developing and underdeveloped countries are rich in bioresources and traditional knowledge. Some such developed countries use the bio resources and traditional knowledge of other countries without proper authorization and/ or compensation to the countries concerned (Biopiracy). Basmati rice grown in India is distinct for its unique flavor and aroma, but an American company got patent rights on Basmati through the US patent and trademark office; the new variety of Basmati has been developed by this company by crossing an Indian variety with semi-dwarf varieties. Now some nations are developing laws to prevent such unauthorized exploitation of their bioresources and traditional knowledge One Mark Questions: 1. Name an abiotic stress that can be tolerated by the genetic modified crop. Cold, Drought, Salt or Heat 2. Give an example of crop in which nutritional value is enhanced? Vitamin A rich rice 3. What is the product of Bt toxin genes? Bt toxin protein Cry 4. Name two Bt toxin genes which code for cry protein? cryiac and cryiiab 5. Name Bt toxin gene which control boll worm and Bt toxin gene which control corn borer? cryiac and cryiab respectively. 6. What is the alternative to enhance crop yield and minimize the use of fertilizers and chemicals for reducing harmful effects? Genetic modifications 7. What is gene therapy? It is a collection of methods that allows correction of a genetic defect that has been diagnosed in a child/embryo. 8. What is unique about transgenic animals?

7 Their DNA is manipulated by the introduction of foreign gene. 9. Define Green Revolution. Increase in yields, try the use of improved crop varieties, better management practices and agrochemicals, is called green revolution 10. What is the significance of traditional knowledge? It can be used to develop modern applications and to save time, effort and expenditure during their commercialization. 11. Name the nematode infested? Meloidegyne incognitia Two Mark Questins: 1. What are Cry proteins? Name an organism that produces it. How has man exploit this protein to his benefit? Cry proteins are toxin producing proteins, produced by bacrerium bacillus thuringiensis. Man uses it to produce insect resistant plants like Bt Cotton 2. Name the enzyme that use in PCR and from which bacterium does it get? DNA Polymerase and obtained from bacterium Thermus aquaticus 3. How insulin is synthesized in humans? Human insulin consists of two short polypeptide chains : chain a and chain B, linked by disulphide bridges. Insulin is secreted as prohormone which has to be processed before it becomes a mature and functional hormone the prohormone contains another polypeptide called C- peptide, which is removed during maturation. 4. Why insecticidal protein present in B. thuringiensis does not kill bacteria? It does not kill the bacteria it exists in the inactive form in the bacterial cell. 5. How human insulin is prepared by recombined DNA technique? Who first successfully made it? In 1983, Eli Lilly an American company, prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of E.coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulphide bonds to form human insulin. 6. How can early detection of disease be done?

8 By using Molecular diagnosis. In this method, a single stranded DNA or RNA, tagged with a radioactive molecule 9probe0is allowed to hybridize to its complementary DNA in a clone cells followed by detection using autoradiography. The clone having mutated gene will notbe able to appear on photographic film, because the probe will not have complimentarity with mutaed gene. 7. What are the most common application of PCR? To detect the disease at a very early state when the concentration of pathogen is very low. 8. How process of RNA interference is employed in tobacco plant to avoid infection of nematode? A nematode Meloidogyne incognita infects tobacco plants and reduces their yield. The specific genes ( in the form of c DNA) from the parasite are introduced into the plant using Agrobacterium as the vector. The genes are introduced in such a way that both sense/coding RNA and antisense RNA (Complimentary to the sense/ coding RNA) are produced. Since these two RNAs are complementary, they from a double stranded RNA (ds RNA) This neutralizes the specific RNA of the nematode, by a process called RNA interference. As result the parasite cannot line in the transgenic host and the transgenic plant protected from the pest 9. How infestation of Meloidegyne incognitia was prevented in tobacco plant? 10. What is the source of complementary strand in mrna silencing? Sorce may be infection by virus having RNA genome(riboviruses) or mobile genetic elements (Transposons) that replicate via an RNA intermediate 11. What is silencing of mrna? Preventing the translation of mrna. 12. What has been done to prevent biopiracy? Developing Laws to prevent unauthorized exploitation of bio-resources and traditional knowledge. Amendment of existing Indian Patent Bill 13. What is ELISA and expand ELISA? ELISA is a technique used for molecular diagnosis or detection of pathogens. Its full form is Enzyme Linked Immun-Sorbent Assay.

9 14. What are the various approaches to treat DNA deficiency disease? Bone Marrow Transplantation Enzyme Replacement Therapy Gene Therapy 15. Write name of two diseases which is detected by PCR. PCR is used to detect HIV in suspected AIDS patients similarly it is used to detect mutations in genes in suspected cancer patients too. 16. Write full form of GEAC. What is its use? Genetic Engineering Approval Committee. It will make decisions regarding the validity of GM research and the safety of introducing GM organisms for public services. 17. Write two genetic modifications of GMO. Answer: Genetic Modification has i) made crops more tolerant to abiotic stresses (cold, draught, salt, heat). ii) reduced reliance on chemical pesticides. (pest resistant crops). 18. A farmer found that agrochemicals cause pollution of soil and water and are too expensive. What alternative should be use? Farmer should use genetically modified crops as a possible solution for given problems Three marks Questions: 1. How can human insulin is prepared by recombinant DNA technique? Who first successfully made it? 2. What are transgenic bacteria? Illustrate using any one example. 3. Compare and contrast the advantages and disadvantages of production of genetically modified crops? 4. Diagrammatically represent the experiment steps inclosing and expressing an human gene into a bacterium like E coli? 5. Explain the structure of proinsulin and how does insulin is formed? 6. What are the three main research areas for industrial scale production of biochemical's?

10 7. Explain three genetic modification in the genetically modified organisms? 8. What is PCR? What are its applications? 9. How ELISA is done? 10. Write short note on: i) Biopatent ii) Biopiracy 11. Study the given flow chart and answer i) Name the define mechanism used ii) In which plant it has been done. iii) Iii) Name the nematode infested? HOST CELL NEMATODE SPECIFIC GENE PRODUTION OF ds RNA in TRANSGENICHOST INFECTION SILENCING OF NEMATODE mrna i.

11 PROTECTED HOST 12. The diagram shows an antibody molecular i) name the parts labeled A to F Ii) State the function of A Iii) Name the types of specific cells that produce antibodies. The diagram shows an antibody molecular i) name the parts labeled A to F Ii) State the function of A Iii) Name the types of specific cells that produce antibodies. 13. Give advantages and drawbacks of each. ADA deficiency disease Bone marrow gene therapy transplantation enzyme replacement therapy 14. What are the three research areas of biotechnology? Five Marks Questions:

12 1. Diagrammatically represent the experimental steps in cloning and expressing a human gene into a bacterium like E.coli 2. What is meant by Gene Therapy? Illustrate using the example of ADA deficiency. 3. Compare the advantages and disadvantages of GMO. HOTS Questions: 1. How is PCR used to detect gene mutations in case of suspected cancer patient? 2. What could be the permanent cure for Adenosine Deaminase Deficiency? Explain % of the transgenic animals produced are mice. How can man benefit from such modifications of animals? 4. How can biotechnology be useful in agriculture? Explain with examples..