Class 12 Biology Chapter 12 Biotechnology and its Applications

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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Also, you can read the SCERT book online in these sections Solutions by Expert Teachers as per SCERT (CBSE) Book guidelines. These solutions are part of SCERT All Subject Solutions. Here we have given Assam Board Class 12 Biology Chapter 12 Biotechnology and its Applications Solutions for All Subjects, You can practice these here.

Q.1. Plasmid is a boon biotechnology. Justify this statement quoting the examples in the field of biotechnological inventions. 

Ans : Plasmids are small circular DNA found in bacteria. These are used as vector in transporting gene (DNA fragment) inside bacteria with a purpose to create recombinant DNA inside the bacteria, For this purpose the plasmid is idown out, la part of the plasmid DNA is removed by endonuclease and in that part another part of desired DNA part collected from another organism is inserted using ligase. 

This plasmid is then allowed to enter the bacterial cell and carry out recombination process. Plasmid therefore plays a vital role in DNA recombination technology without which it would have been impossible to carry out genetic engineering. It is therefore an important tool in genetic engineering. 

For example, the gene coding for insulin in mice had been transferred to E coli which then started producing insulin. In another case, the vaccine against Foot and Mouth Disease of cows had been prepared by transferring VIP gene of virus causing the disease to E coli which on vaccination creates antibody against the virus.

Q.2. Expand the name of enzyme ADA. Why is the enzyme essential in the human body? Suggest a gene therapy for its deficiency. 

Ans : ADA means Adenosine deaminase. It is an enzyme which offer immunity to certain disease. The enzyme is synthesised only when the gene responsible for coding the enzyme present in the cells of the body. 

If the gene is not present in the body the same may be implanted in the body by genetic engineering. This is a kind of gene therapy. For this purpose the some lymphocyte cells of the diseased person is taken out to multiply such cells artificially. After that the gene responsible for coding ADA is inserted into the lymphocyte cells and the lymphocyte cells carrying the implanted gene are inserted into the body of the diseased person. If this can be done in the embryonic stage than the body remain protected whole life. 

Q.3. What are Cry proteins? Name the organisms that produces them. How has man exploited these proteins to his benefit. 

Ans : Cry-protein means crystal protein. There are many types of it. A bacterium called Bacillus thuringiensis produces it. A gene named cry gene is responsible for its production of a toxic substance which kills a wide variety of insects. Through genetic engineering this cry gene is inserted in the plant body which in turn develops ability to defend itself from the attack of the pest. A good number of crops have been developed having this property. Bt cotton, Bt corn, Bt brinjal are some such crops. Such crops need not be protected with the help of pesticides.

Q.4. What are GMOS? Write at least four main objectives of genetically modified crops plants. 

Ans : GMOS (genetically modified organisms) are those organisms in which foreign gene taken from another organism having code for specific property is inserted in the DNA of the host using genetic engineering. The organism in turn acquire the desired quality. 

Main objectives : 

(i) To reduce the dependence upon pesticide. 

(ii) Offer the plant the ability to resist the adverse physical and environmental stress. 

(iii) Enhancing self-life to crops. 

(iv) Increasing the nutrients of the foods. 

(v) Increase the productivity also.

Q.5. What do you mean by GEAC? What are its role?

Ans : GEAC stands for Genetic Engineering Approval Committee. We know that Genetic engineering a great potentiality. It has already shown great promises in the field to biotechnology. Medical science and agricultural science has already made tremendous progress due to it. A large variety of chemical substances are now produced using biotechnology. In many cases new organisms have been created using genetic engineering for their production. The ability to create transgenic variety of animals and plants has shaken the scientific as well as social circles world over. 

It is believed that unless some restriction is not created the genetic engineers in their new found ability may shaken the very fabric of the ethical standard. They may be able to create such creatures or human form artificially which may not be good for ethical reason. Again they may create such plant or animal species which in the long run will adversely affect the natural balance and productivity. Therefore to impart a reasonable restrain GEAC have been formed in all countries. This committee will scrutinize the impact of any transgenic form before it is released. 

Q.6. How does the toxic insecticide protein produced by bacterium in Bt cotton kill the insect pest but not the cell of Bacillus thuringiensis, where the toxic protein is generated. 

Ans: 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 in USA and Latin America for its potentiality to produce biofuel. Corns are extensively damaged by corn borer! Similarly cotton all over the world is destroyed by budworms, bollworms etc. Resistance to such pest can be induced in plant itself by genetic engineering. Bt stands for a bacterium, Bacillus thuringiensis. This bacterium produce a toxin harmful for pest that damages crops like corn, cotton and others. 

The Bt gene of the bacterium has been cloned and introduced into the crop to provide toxic .cetoute crop itself start secreting toxin for the pest. The gene UG gcb crop that code for Bt toxin is called cry gene. There are different types of cry genes that code for different types of toxins (protein). For example the cry gene that codes for toxin specific for cotton is crylAc and that of corn is crylab. The bacterium which produce the toxin is itself not affected by it because the toxin protein remain in inactive form (protoxin) within it, but as soon as the toxin protein is ingested by an insect pest, it dissolves in its alkaline pH of the gut and starts action.

Q.7. What are antibiotics? Giye a list of organisms used for production of different antibiotics mentioning against their names. 

Ans : Antibiotics are special kinds of chemo therapeutic agents usually obtained from living microorganisms. These are metabolic products of these organisms. The metabolic product of these microorganisms which are detrimental or inhibitory to other microorganisms in very small amount are called antibiotic. These antibiotics are obtained from some specific microbes and are produced commercially using industrial microbiological process. The first antibiotic was penicillin obtained from a fungus called Penicillium chrysogenum. 

Some Antibiotics of importance :

Q.8. What is a transgenic crop? State the advantages of the technique involved in the production of transgenic crop over breeding activities. 

Ans : The crop which has been modified by inserting gene from other source to impart it with certain added characters it is called transgenic and the plant is called transgenic plant.

In normal breeding technique the process of emasculation and dusting of desired pollen grains is follow to impart desired quality to the plants or crops. In transgenic technique a suitable part of DNA drawn from another species that codes for specific character is inserted into the genome of the crop to impart the desired character.

Q.9. Name a-insect pest that is killed by the product of cry 1 AC gene. Explain how the gene makes the plant resistant to the insect pest. 

Ans : Proteins encoded by the genes ‘cry IA’c and cry II Ab control te cotton ball worm and that of cry 1Ab controls the corn borer. I-amysna The cry protein is toxic to larvae of certain insects as lepidopteran (Tobacco bud worm, army warm) celeopters (beetles) and dipteran (flies). 

Q.10. What are various advantages of using genetically modified plants to increase the overall yield of the crop? 

Ans : The advantages genetically modified organisms are : 

(i) They can tolerate the physical and environmental stress such as cold, drought, salt and temperature. 

(ii) They can resist the pest attack and thereby reduce dependence on pesticide.

(iii) They can tolerate the herbicides. 

(iv) They reduce post harvest loss.

(v) They have increased self-life fruits and Vegetables. 

(vi) They have improved food value. 

(vii) They have improve productivity of stanh and oil.

Dev Kirtonia

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