Class 12 Biology Chapter 12 Biotechnology and its Applications The answer to each chapter is provided in the list so that you can easily browse through different chapters Assam Board HS 2nd Year Biology Chapter 12 Biotechnology and its Applications Question Answer.
Class 12 Biology Chapter 12 Biotechnology and its Applications
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IV. Long Question 5 Marks :
Q.1. Write notes on:
(a) Gene therapy
Ans : Each gene is specific for an enzyme. Therefore for synthesis of every enzyme one gene is required which must be specific for that enzyme. In the absence or defect of a particular gene certain enzyme required to change a metabolic product for the next step to start with not be synthesised. As a result the chain of metabolic reaction which normally ends with production of a substance essential for functioning of the life system stops without completing the chain of reaction. This give rise genetic disease which normally cannot be cured. Gene therapy aims to remove such defect at the embryonic state by injecting correct gene. Permanent cure is still not possible in adult. Bone marrow transplantation, enzyme replacement therapy, infusion of genetically engineered lymphocytes of blood do not bring permanent cure unless treated at embryonic stage.
In the above scheme the substrate ‘C’ has not changed because the enzyme needed to change it to the next product is not available due to the defect of the gene responsible for its production. Therefore the substrate “C’ will accumulate in the body causing suffering which cannot be cured by any drug. Only gene therapy at the embryonic shape can cure it completely.
(b) Genetically engineered insulin
Ans : Genetic engineering has achieved great height in terms of application in medical and agriculture. It was given clue to develop new organisms not present earlier in the history of evolution. It can now modify in genetic quality of animal and plants. With a view to make them more productive nutritive and resistant to physical and chemical stress. But unregulated manipulation of living organism cannot be allowed as this act may creates organisms which if allowed to breed freely in nature may lead to change ecological balance. The intermixing of modified organisms with natural population may lead to unpredictable consequences. Moreover, ethical issue such a moral right of human being to modify nature’s creation, infringement on animal right etc. must be considered.
There fore, in line with the decision of various governments aid United Nation guidelines the Government of India has constituted a regulatory committee or authority Named Genetic Engineering Approval Committee (GEAC). This committee is responsible for all issues concerning genetically modifications research and validates of the product before introduced for the public services. i.e. available in the market. The food value, side effect etc. are also checked by this approved authority.
(c) Ethical issues of biotechnology.
Ans : When human being fails to synthesis insulin in his or her body must take insulin does to get rid of problems associated with diabetes. Earlier insulin was obtained by extracting from pancreas of slaughtered animals. It was a costly and troublesome process as a huge number of animals needed to be reared. Moreover, the insulin of animal origin sometime caused allergic reaction in human being. All these could be overcome by use of genetic engineering. Genetic engineers chosen microorganism in place of animal. It is easier to handle microorganisms, require less time and the cost of production is also less.
The schematic figure shows that DNA obtained from pancreas of rat (DNA can be artificially synthesized also) is cut out to isolate the precise segment responsible for insulin biosynthesis. The DNA segment is then joined with plasmid separated from E. coli bacteria using ligase. The recombinant DNA (plasmid plus isolated DNA fragment) is than incorporated in the same type of bacteria. The bacteria will multiply along with its recombinant DNA. The bacteria having such insulin coded DNA fragment in their cells, will secrete insulin in culture which can be isolated easily. Thus the technology ensures steady supply of insulin of commercial scale.
Q.2. What is the principle of PCR technique? Mention the role of PCR in molecular diagnosis.
Ans : The polymerase chain reaction or PCR multiplies copies of DNA or its segments in vitro using two sets of primers which are small chemically synthesized oligonucleotides complementary to the regions of DNA and. an enzyme called DNA polymerase. The enzyme polymerase extend the primers using nucleotides provided in the reaction and the DNA part provided as template. The process of replication can be repeated and a billion copies of the DNA can be multiplied. Thus a small fraction of DNA can be multiplied for study and use in genetic engineering.
Molecular Diagnosis using PCR : The methods of diagnosis of diseases are now undergoing rapid change. Earlier, the diagnosis of pathophysiology was based on analysis of blood, urine, stool etc. Later methods like Polymer Chain. Reaction, Enzyme Linked Immuno-sorbent Assay (ELISA), Widal test, Fluorescent Antibody Technique and such other tests are being carried out for diagnosis of infection. The problem associated with such diagnosis is that the symptoms of diseases are produced only when the population of infectious agents increase too much.
However, using PCR technique even presence of small amount of infectious agent can be detected by amplifying their nucleic acid. This is used in detection of HIV in suspected AIDS patients. The presence of mutant genes in case of suspected career patient may also be detected by PCR. In this case a single stranded DNA or RNA is tagged with radioactive molecule and allowed to hybridize its complementary strand in clone of the cells. This is then detected using autoradiography. The film that will be produced will not show the clone having mutated genes, because the radioactive molecule used as probe will not have complementary part of mutated genes.
ELISA test is an antigen-antibody reaction test. It detects specific virus, bacteria, toxins present in serum by detecting the presence of antigens which reacts with known antibody used for test.
Q.3. What are bioresources? How are industrialised nations exploiting the bioresources? Explain it by taking any example.
Ans : All plants, animals and microorganisms which sustain our livelihood, maintain the balance of nature and perpetuate are bioresources. We depend upon them for our food, cloth, fibres, medicine, building materials etc.
They are the genetic resources evolved through million years in interaction with nature. Each region, each country and each continent and sub- continent has peculiar bioresources of its own. Wanton destruction of natural areas, habitats and excessive use by human being are causing their gradual extinction.
Developed countries have developed sophisticated technology to propagate and multiply many bioresources with ease. So they are in search for such bioresources which are not found in their countries but have great commercial value. They take resource to biopiracy. What they do with these? They using genetic engineering manipulate certain quality and patent these as of their own development. The country from where they have collected these are deprived of the right to produce these. Indian Basmati Rice, Neem, Tulsi, Turmeric etc. are similarly patented but due to strong protest from the Indian Government, they have not been successful.
Q.4. “Biotechnology can greatly promote human welfare, but it can also be misused to increase human sufferings”. Comment on the statement with the help of suitable examples.
Ans : The contribution of biotechnology for human welfare is outstanding. It has so much of potentiality that it can lay hands in all branches of science which are directly related to human welfare. It can produce not of new drugs, increase food production. Genetically engineered drugs. Food crops, animals are going to revolutionise to concept of productivity. It can create new organism having additional eladity. The rate at which the technology is progressing the world may witness both positive and negative impact of it. While the positive sides have been hinted above the negative sides are dangerously hazardous and potential enough to disintegrate the moral and ethical values of life and society.
Some of the possible evil consequences of genetic engineering are:
(i) Possibility of developing germs which are resistant to known antibiotics to be used for biological warfare.
(ii) Accidental production and escape of some potentially dangerous owls organisms which may cause environmental imbalance.
(iii) There may be tendency to produce monsters, robots, or a dictator may decide to create thousands of subhuman creatures for specific purposes. All these would lead to a situation in which natural process of human evolution and societal relationship would be disturbed.
(iv) The green foods may certain toxin and these may pollute other crops and thereby diversity of crops my be affected.
Q.5. What are the differences between conventional agricultural practices and modern agricultural practise. State the answer giving examples.
Ans : Conventional agriculture depends upon sustainable cycles of rain, nutrient pest and pathogen. No chemical fertilizer, pesticides and irrigation was necessary. Pest and diseases are biologically controlled. It is dependent upon rain. Crop rotation is followed organic manure is used.
But as the demand for more food has increased the limited area of agriculture field is not been able to supply us increased demand. Agriculturists now to grow more food have taken recourse to modern method.
The modern method is based on three approaches :
(i) Agriculture based on ago-chemicals such as chemical fertilizer, pesticides, herbicides.
(ii) Agriculture based on organic input such as manure, bio-fertilizer, bio-controlling agents.
(iii) Agriculture based on genetically modified crops.
We are aware of the last great leap forward in agriculture in the 5th and 6th decades of the last century. The hybridization technique created such an impact in agriculture that high yielding varieties of major crops had revolutionised our agriculture. This agricultural revolution was called green revolution: Agriculture production has increased not only for the high yielding varieties but also because of improved management practice, use of more fertilizer, more water etc.
Even then the production of food is not sufficient to feed the entire population adequately. Moreover, the cost of ago-chemicals are increasing, day-by-day and with the existing varieties and with the use of existing agro-chemicals the level of production cannot be increased further. More and more use of ago-chemicals are also harmful to our environment. Țherefore agro-scientists are looking for alternatives method to boost agriculture.
The development of genetically modified organisms (GMO) is the latest tool in the hands of agriculturists for increasing crop yield. GM plants are efficient in many ways.
Specific GM crop has specific ability such as:
(i) tolerate physical and environmental stress such as cold, draught, basalt, temperature.
(ii) resist pest attack and thereby reduce dependence on pesticides.
(iii) tolerate herbicides.
(iv) reduce post-harvest loss.
(v) increase self-life of fruits and vegetables,
(vi) Improves the food value.
(vii) Improves the productivity of starch and oil.
The most successful GM crops are Bt corn and Bt. cotton. Corn is a major food and fuel crop. It is cultivated all over the world particularly is USA and Latin America for its potentiality to produce biofuel.
Many different kinds of such GM crops have been developed. Development of GM crops however is not free from the controversy.
Q.6. One of the main objective of biotechnology is to minimise the use of insecticides on cultivated crops. Explain how insect resistant crops have been developed by using techniques of biotechnology.
Ans : Conventional agriculture depends upon sustainable cycles of rain, nutrient pest and pathogen. No chemical fertilizer, pesticides and irrigation was necessary. Pest and diseases are biologically controlled. It is dependent upon rain. Crop rotation is followed organic manure is used.
But as the demand for more food has increased the limited area of agriculture field is not been able to supply us increased demand. Agriculturists now to grow more food have taken recourse to modern method.
The modern method is based on three approaches:
(i) Agriculture based on ago-chemicals such as chemical fertilizer, pesticides, herbicides.
(ii) Agriculturė based on organic input S1s e bio-controlling agents.
(iii) Agriculture based on genetically modified crops.
You are aware of the last great leap forward in agriculture in the 5th and 6th decades of the last century. The hybridization technique created such an impact in agriculture that ! revolutionised our agriculture. This agricultural revolution was called green revolution. Agriculture production has increased not only for the high yielding varieties but also because of improved management practice, use of more fertilizer, more water etc. Even then the production of food is not sufficient to feed the entire population adequately. Moreover, the cost of ago-chemicals are increasing, day-by-day and with the existing varieties and with the use of existing agro-chemicals the level of production cannot be increased further. More and more use of ago-chemicals are also harmful to our environment. Therefore agro-scientists are looking for alternatives method to boost agriculture.
The development of genetically modified organisms (GMO) is the latest tool in the hands of agriculturists for increasing crop yield: GM plants are efficient in many ways.
(i) tolerate physical and environmental stress such as cold, draught, salt, temperature.
(ii) resist pest attack and thereby reduce dependence on pesticides.
(iii) tolerate herbicides.
(iv) reduce post-harvest loss.
(vi) Improves the food value.
(vii) Improves the productivity of starch and oil.
The most successful GM crops are Bt corn and Bt. cotton, Corn is a major food and fuel crop. It is cultivated all USA and Latin America for its potentiality to produce biofuel. world particularly is Dosm Many different kinds of such GM crops have been developed. Development of GM crops however is not free from the controversy.
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