CBSE Class 12 Biology HOTs Biotechnology And Its Applications

Very Short Answer Questions

Question. For which variety of Indian rice, patent was filed by a USA Company?
Answer. Indian Basmati was crossed with semi-dwarf variety and was claimed as a new variety for which the patent was filed by a USA company.

Question. Use of —————– is considered to be the solution by which the farmers can get maximum yield by minimum use of fertilizers and chemicals ? 
Answer. Genetically Modified crops

Question. State the role of transposons in silencing of mRNA in eukaryotic cells. 
Answer. Transposons or mobile genetic elements in viruses are the sources of the complementary dsRNA,which in turn bind to specific mRNA and cause RNA interference of the parasite.

Question. Proteins encoded by genes ‘cry IAc’ and ‘cry IIAb’ and that of ‘cry IAb’are slightly different in their control.’ What is the logic behind this statement? 
Answer. Proteins encoded by genes ‘cry IAc’ and ‘cry IIAb’ control Boll Worms. Proteins encoded by genes ‘cry IAb’ controls corn borer.

Question. Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves. What is the reason behind it? 
Answer. Cry protein of bt toxin in Bacillus thuringiensis is produced in an inactive state. (pro-toxin). It remains inactive until subjected to alkaline pH.

Question. A boy has been diagnosed with ADA deficiency. Suggest any one possible treatment.
Answer. Bone marrow transplant/enzyme replacement therapy/gene therapy.

Question. Name two genetically modified hormones.
Answer. Insulin and human growth hormones.

Question. A committee has been constituted by the Indian govt . Which is meant to take decisions regarding the validity of Gm research and safety measures of introducing GMO’s for public service. Name it? 
Answer. GEAC (Genetic Engineering Approval Committee)

Question. A method to present infestation of a nematode Meloidegyne incognitia on roots of tobacco is silencing the specific mRNA. What is the scientific name of the technique? How is this performed by ds-RNA?
Answer. RNA interference (RNAi) This technique involves silencing of specific mRNA due to a Complementary ds RNA molecule that binds to and prevents translation of m RNA i.e. RNA has been silenced.

Question. Write the two uses of PCR technique in diagnosis.
Answer. Two uses of PCR technique:
(i) It is used to detect HIV in suspected AIDS patients.
(ii) It is used to detect mutations in gene, in suspected cancer patients.

Question. (a) Mention the cause and the body system affected by ADA deficiency in humans.
(b) Name the vector used for transferring ADA-DNA into the recipient cells in humans. Name the recipient cells.
Answer. (a) The cause is the defective gene not producing ADA. The immune system is affected.
(b) A retroviral vector is used, recipient cells are lymphocytes.

Question. Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because—
(a) bacteria are resistant to the toxin; (b) toxin is immature;
(c) toxin is inactive; (d) bacteria encloses toxin in a special sac.
Answer. (c) toxin is inactive.

Question. PCR requires very high temperature conditions where most of the enzymes get denatured.
How was this problem resolved in a PCR? 
Answer. This problem was resolved by the use of a thermostable DNA polymerase, Taq polymerase derived from Thermus aquaticus which remains active during the high temperature and induces denaturation of double stranded DNA.

Question. Name a molecular diagnostic technique to detect the presence of a pathogen in its early stage of infection. 
Answer. ELISA (Enzyme Linked Immunosorbent Assay)

Question A multinational company uses the bio-resources without proper authorization from the country concerned. What is the term given to this unauthorized use? 
Answer. Biopiracy.

Short Answer Questions

Question. Why are yeasts used extensively for functional expression of eukaryotic genes? 
Answer. Yeasts are simplest unicellular eukaryotic organisms and like bacteria they are genetically well characterised, easy to grow and manipulate. They can be readily cultured in small culture vessels as well as in large-scale bioreactors.

Question. A cotton plant is produced by DNA technology which is resistant to bollworms. Name the variety of cotton .Also name the organism from which the gene for this Resistance has been exploited? 
Answer. Bt cotton  Bacillus thuringiensis( bacterium)

Question. Gene therapy is an attempt to correct a genetic defect by providing a normal gene into the individual. By this the normal function can be restored. Alternate method would be to provide the gene product (protein/enzyme) known as enzyme replacement therapy, which would also restore the function. Which in your opinion is a better option? Give reason for your answer.
Answer. Gene therapy would be a better option because it has the potential to completely cure the patient.
It is because the correct gene once introduced in the patient, can continue to produce the correct protein enzyme. Enzyme therapy does not offer permanent cure as it needs to be given to the patient on regular basis. It is also more expensive.

Question. ELISA technique is based on the principles of antigen and antibody interaction. Can this technique be used in the molecular diagnosis of a genetic disorder, such as phenylketonuria?
Answer. Yes. One can use antibody against the enzyme (that is responsible for the metabolism of phenylalanine) to develop ELISA-based diagnostic technique. The patient in which the enzyme protein is absent would give negative result in ELISA when compared to normal individual.

Question. Compare and contrast the advantages and disadvantages of production of genetically modified crops.
Answer. Advantages of genetically modified crops:
• Reduces the use of chemical fertilisers and pesticides which cause pollution (air, water and soil).
• Production of new resistant varieties against pathogen, droughts, salinity, etc.
• Provides raw materials to industries like pharmaceuticals.
• Genetically modified crops have enhanced nutritional quality and yield.
• These crops grow fast and produce high yield through modifications.
Disadvantages of genetically modified crops:
• Proteins produced by GM organisms might cause allergy and other reactions.
• Resistance characters might develop in intestinal bacteria against antibiotics.
• Resistant genes transferred by pollen to the weeds may also become resistant to pests.

Question. PCR is a useful tool for early diagnosis of an infectious disease. Comment. 
Answer. PCR is a very sensitive technique which enables the specific amplification of desired DNA from a limited amount of DNA template. Hence, it can detect the presence of an infectious organism in the infected patient at an early stage of infection (even before the infectious organism has multiplied to large number).

Question. (a) Tobacco plants are damaged severely when infested with Meloidogyne incognita. Name and explain the strategy that is adopted to stop this infestation.
(b) Name the vector used for introducing the nematode specific gene in tobacco plant.
Answer. (a) Gene expression can be controlled by using RNA molecule and this technology is called RNA interference or RNAi or gene silencing. During this process nematode specific gene
is introduced into host plant (using Agrobacterium) which produces dsRNA. This silences specific mRNA of the nematode and parasite dies.
(b) Agrobacterium tumifaciens.

Question. What will happen if some how the pH of the gut of caterpillar is sustained acidic rather than basic (alkaline) and they are subjected to carry – protein produced by Bacillus thurin giensis ? 
Answer. Bt toxin protein (Cry-protein) exists in its inactive form as pro-toxin.
When it enters the gut of the caterpillar then in the alkaline pH, it gets activated ( toxin). It becomes soluble, attaches to the wall of the gut, causes swelling and lysis. No alkaline pH in the gut, no activation of pro-toxin, toxin ineffective ,caterpillar would not die.

Question. A baby loses his mother in infancy .He was totally depended on breast feeding as cows milk creates digestive problems. Name the first cow whose milk is nutritionally more balanced than normal cow’s milk. Which extra nutritional element does it contain and how much magnitude? 
Answer.. First GM cow(transgenic cow)-Rosie
Rosie produced milk rich in human protein
Human protein-Human alpha lact-albumin (2.4g/l) (More balanced product for human babies than the milk of normal cow)

Question. What is Biopiracy? State the initiative taken by the Indian Parliament towards it.
Answer. Biopiracy is the use of bioresources by organisations without proper authorisation from the countries and people concerned without compensatory payment.
The government has cleared patent terms, emergency provisions and research and development initiative.

Question. What is gene therapy? Illustrate using the example of adenosine deaminase (ADA) deficiency.
Answer. Gene therapy is a method which corrects or replaces the defective genes. In 1900, first clinical gene therapy was given to a 4-year old girl with adenosine deaminase (ADA) deficiency. This enzyme plays an important role in functioning of immune system. This disorder is caused due to the deletion of the gene for adenosine deaminase. In gene therapy, lymphocytes from the blood of the patient are grown in a culture outside the body. A functional ADA cDNA (using a retroviral vector) is then introduced into these lymphocytes, which are returned to the patients. 
However, as these cells are not immortal, hence the patient requires periodic infusion of such genetically engineered lymphocytes.

Question. How has recombinant technology helped in large scale production of vaccines? Explain giving one example. 
Answer. Production of insulin by rDNA techniques was achieved by an American company, Eli Lilly, in 1983. It prepared two DNA sequences corresponding to A and B chains of human insulin and introduced them in plasmids of E. coli for production. The A and B chains produced were separated, extracted and combined by creating disulfide bonds to form human insulin.

Question. Shahid a two years old baby is deficient in his immune system since birth. His father was told that this was due to an enzyme deficiency which is crucial for the immune system to function. Name the enzyme, the cause of its deficiency and the cure of the disease? 
Answer. Enzyme ADA (adenosine deaminase) Cause- deletion of a gene for ADA Cure of the diseasea)
a)bone marrow transplant
b) Enzyme replacement therapy
c) Gene therapy on lymphocytes
d) Introduction of gene from bone marrow cells producing ADA in to cells at early embryonic stage (for permanent cure)

Question. State the cause of adenosine deaminase enzyme deficiency. 
Answer. Deletion of gene for adenosine deaminase.

Question. What is “Flavr Savr”?
Answer. It is a transgenic tomato variety which has blocked production of polygalacturonase.

Question. Suggest any two possible treatments that can be given to a patient exhibiting adenosine deaminase deficiency.
Answer. (i) Enzymes replacement therapy (in which functional ADA is injected)
(ii) Bone marrow transplantation
(iii) Gene therapy/Culturing the lymphocytes followed by introduction of functional ADA
(iv) DNA into it and returning it into the patient’s body. (Any two)

Question. Why do children cured by enzyme-replacement therapy for adenosine deaminase deficiency need periodic treatment? 
Answer. As enzyme replacement therapy does not cure the disease completely, it requires periodic treatment.

Question. What are Cry proteins? Name an organism that produce it. How has man exploited this protein
to his benefit?
Answer. Cry protein (crystal protein) is a toxin coded by a gene cry and is poisonous to some insects, thus giving resistant characters to the plants. Bacillus thuringiensis produces Cry protein. Cry protein producing gene is transferred to the plants to provide resistance against insect larvae. Man has developed several transgenic crops by introducing these genes from bacteria to crop plants such as Bt cotton, Bt corn, etc.

Question. What are transgenic animals? Give an example. 
Answer. Animals that have had their DNA manipulated, to possess and express an extra (foreign) gene are known as transgenic animals. Example, Rosie is a transgenic cow.

Question. What is biopiracy? 
Answer. Biopiracy is the use of bioresources by multinational companies and other organisations without proper authorization or compensation payment to the concerned country or organisation.

Question. State the purpose for which the Indian Government has set up GEAC.
                                             OR
Mention two objectives of setting up GEAC by our government. 
Answer. GEAC was set up to make decisions regarding the validity of GM research and the safety of introducing GM-organisms for public services.

Question. What are transgenic bacteria? Illustrate using any one example.
Answer. The bacteria whose DNA is manipulated to carry and express a foreign DNA is called transgenic bacteria. These microbes are used for producing important biochemicals. They have been synthesising alcohol, enzymes, steroids and antibiotics. Example, Bacillus thuringiensis for Bt cotton. For details refer basic concept point 1(i) and 2(i).

Short Answer Questions

Question. Differentiate between gene therapy and gene cloning.
Answer. Table 12.1: Difference between Gene Therapy and Gene Cloning

Question. Explain how a hereditary disease can be corrected. Give an example of first successful attempt made towards correction of such diseases. 
Answer. A hereditary disease can be corrected by gene therapy. In this method, normal genes are inserted into a person’s cells and tissues to treat a disease.
The first successful attempt for gene therapy was done for adenosine deaminase (ADA) deficiency.

Question. What is GEAC and what are its objectives? 
Answer. GEAC (Genetic Engineering Approval Committee) is an Indian government organisation. Its objective are to:
(a) examin ethe validity GofM (Genetic modificatio nof organismr)e search.
(b) inspect the safety of introducing GM for public services and for their large scale use.

Question. A person is born with a hereditary disease, suggest the possible corrective method for it. Illustrate by giving a specific example.
Answer. The possible corrective method is gene therapy.
For example, ADA (Adenosine deaminase) deficiency has been treated through gene therapy.
Lymphocytes from the blood of the patient are grown in a culture. A functional ADA cDNA is introduced into these lymphocytes, which are subsequently returned to the patient. The permanent cure is done by introducing ADA cDNA into cells at early embryonic stages.

Question. Write the functions of adenosine deaminase enzyme. State the cause of ADA deficiency in humans. Mention a possible permanent cure for a ADA deficiency patient. 
Answer. Adenosine deaminase enzyme is responsible for the proper functioning of the immune system.
ADA deficiency is caused by deletion of gene for adenosine deaminase. A possible permanent cure would be gene therapy, if it is detected at early embryonic stage.

Question. How is a mature, functional insulin hormone different from its pro-hormone form?
Answer. Mature functional insulin is obtained by processing of pro-hormone which contains extra peptide called C-peptide. This C-peptide is removed during maturation of pro-insulin to insulin.

Question. Why is the functional insulin thus produced considered better than the ones used earlier by diabetic patients?
Answer. The insulin prepared by rDNA technology does not produce sensitive allergic reactions and immunological reactions whereas those used earlier produced allergic reactions and other complications to the foreign protein as earlier they were extracted from pancreas of slaughtered cattle or pigs.

Question. Why do the toxic insecticidal proteins secreted by Bacillus thuringiensis kill the insect and not the bacteria itself? 
Answer. The Bt toxin protein exists as inactive protoxins but once an insect ingests the inactive toxin, it is converted into an active form of toxin due to the alkaline pH of the gut which solubilise the crystals. Therefore, it does not kill the bacteria.

Question. What is gene therapy? Name the first clinical case where it was used. 
Answer. Gene therapy is a collection of methods that allows correction of a gene defect that has been diagnosed in a child/embryo.
Genes are inserted into an individual’s cells and tissues to treat disease.
The first clinical case where it was used was for caring Adenosine deaminase (ADA) deficiency.

Question. Why is the introduction of genetically engineered lymphocytes into an ADA deficiency patient not a permanent cure? Suggest a possible permanent cure. 
Answer. Introduction of genetically engineered lymphocytes into an ADA deficiency patient is not a permanent cure because these cells are not immortal and the patient requires periodic infusion of such genetically engineered lymphocytes. A possible permanent cure can be isolating the gene producing adenosine deaminase (ADA) from bone marrow cells and introducing it into cells at early embryonic stages.

Question. Differentiate between the insulin produce by rDNA & insulin produce by pancreas.
Answer.
rDNA                                                       Insulin produced by pancreas
i) It is produced artificialy                            i) It is produced naturally
ii) It produces only A & B polypeptides       ii) It has three
polypeptides                                              A,B& C before maturation

Question. How have transgenic animals proved to be beneficial in:
(a) Production of biological products?
(b) chemical safety testing? 
Answer. (a) Rosie–the transgenic cow, produced human proteins containing human α-lactalbumin.
Transgenic animals have been made to produce α-1-antitrypsin used to treat emphysema.
(b) Toxicity testing – Transgenic animals are more sensitive to toxic substances, so the results are obtained in less time.

Question. I) Expand GMO . What are the uses of G.M. Pants ?
Answer. Genetically Modified Organism.
i)It tolerates abiotic stresses such as cold ,drought salt & heat.
ii)It reduces reliance / dependence on chemical pesticides
iii) It reduces post harvest loses.
iv) It increases efficiency of mineral utilization by plants.
v)Enhances nutritional value of food

Question. Match the following
               A                                                                 B
      i) Bt toxin                                                    i) Human alpha lactalbumin
     ii) CryIAc& cryIIAb                                 ​​​​​​​    ii)Emphysema
    iii) CryIAb                                                 ​​​​​​​   iii) Bacillus thuringiensis
    iv) α-1 –antitrypsin                                    ​​​​​​​ iv) Corn borer
    v) Produce of transgenic cow Rosie         v) cotton bollworms

Answer. i) Bt toxin — ——————————— —-Bacillus thuringiensis
ii) CryIAc&  cryIIAb—————————- —–Cotton bollworms i
ii) CryIAb ——————————————– Corn borer
iv)  α-1 –antitrypsin ———————————Emphysema
v) Produce of transgenic cow Rosie ———— Human alpha lactalbumin.

Question. Give one word
i)Supply of alternative resources to industries In the form of starches fuels & pharmaceuticals.
ii New strategy adopted to protect the tobacco Plant infestation by Meloidogyne incognitia.
iii)Technique based on the principle of antigen antibody interaction.
iv) Uses of bioresource by multinational companies/other organization without  proper authorization from the concernedparties.
v) Decision making organization regardingvalidity of G.M resources & the safety of introducing G.M crops.

Answer. i)Supply of alternative resources to industries in the form of starches fuels & pharmaceuticals.                                          i)Tailor-made plants
ii New strategy adopted to protect the tobacco plant infestation by Meloidogyne incognitia                                                               ii) RNA interference
iii)Technique based on the principle of antigen antibody interaction                                                                                                    iii) ELISA
iv)Uses of bioresources by multinational companies /other organization whitout proper authorization from the concerned parties   iv)Biopiracy
v) Decision making organization regardingvalidity of G.M. resources & the safety of introducing G.M. crops                                     v)GEAC

Ques. Which one of the following is now being commercially produced by biotechnological procedures?
(a) Nicotine
(b) Morphine
(c) Quinine
(d) Insulin 

Answer: D

Ques. The genetic defect–adenosine deaminase (ADA) deficiency may be cured permanently by
(a) administering adenosine deaminase activators
(b) introducing bone marrow cells producing ADA into cells at early embryonic stages
(c) enzyme replacement therapy
(d) periodic infusion of genetically engineered lymphocytes having functional ADA cDNA.

Answer: B

Ques. Human insulin is being commercially produced from a transgenic species of
(a) Rhizobium
(b) Saccharomyces
(c) Escherichia
(d) Mycobacterium. 

Answer: C

Ques. ELISA is used to detect viruses where the key reagent is
(a) alkaline phosphatase
(b) catalase
(c) DNA probe
(d) RNase. 

Answer: A

Ques. Maximum application of animal cell culture technology today is in the production of
(a) insulin
(b) interferons
(c) vaccines
(d) edible proteins.

Answer: C

Ques. The term ‘humulin’ is used for
(a) hydrolytic enzyme
(b) powerful antibiotic
(c) human insulin
(d) isoenzyme. 

Answer: C

Ques. Hybridoma cells are
(a) only cells having oncogenes
(b) product of spore formation in bacteria
(c) nervous cells of frog
(d) hybrid cells resulting from myeloma cells.

Answer: D

Ques. Maximum number of existing transgenic animals is of
(a) fish
(b) mice
(c) cow
(d) pig. 

Answer: B

Ques. Read the following four statements (A-D) about certain mistakes in two of them.
(A) The first transgenic buffalo, Rosie produced milk which was human alpha-lactalbumin enriched.
(B) Restriction enzymes are used in isolation of DNA from other macromolecules.
(C) Downstream processing is one of the steps of rDNA technology.
(D) Disarmed pathogen vectors are also used in transfer of rDNA into the host.
Which of the two statements have mistakes?
(a) B and C (b) C and D
(c) A and C (d) A and B 

Answer: D

Ques. Genetic engineering has been successfully used for producing
(a) transgenic mice for testing safety of polio vaccine before use in humans
(b) transgenic models for studying new treatments for certain cardiac diseases
(c) transgenic cow-Rosie which produces high fat milk for making ghee
(d) animals like bulls for farm work as they have super power. 

Answer: A

Ques. Production of a human protein in bacteria by genetic engineering is possible because
(a) the human chromosome can replicate in bacterial cell
(b) the mechanism of gene regulation is identical in humans and bacteria
(c) bacterial cell can carry out the RNA splicing reactions
(d) the genetic code is universal. 

Answer: D

Ques. In transgenics, expression of transgene in target tissue is determined by
(a) enhancer
(b) transgene
(c) promoter
(d) reporter. 

Answer: D

Ques. The transgenic animals are those which have
(a) foreign RNA in all its cells
(b) foreign DNA in some of its cells
(c) foreign DNA in all its cells
(d) both (a) and (b). 

Answer: C

Ques. A ‘new’ variety of rice was patented by a foreign company, though such varieties have been present in India for a long time. This is related to
(a) Co-667
(b) Sharbati Sonora
(c) Lerma Rojo
(d) Basmati. 

Answer: D

Ques. In India, the organisation responsible for assessing the safety of introducing genetically modified organisms for public use is
(a) Indian Council of Medical Research (ICMR)
(b) Council for Scientific and Industrial Research (CSIR)
(c) Research Committee on Genetic Manipulation (RCGM)
(d) Genetic Engineering Appraisal Committee (GEAC). 

Answer: D

Ques. Use of bioresources by multinational companies and organisations without authorisation from the concerned country and its people is called
(a) bio-infringement
(b) biopiracy
(c) biodegradation
(d) bioexploitation.

Answer: B

Ques. Which body of the Government of India regulates GM research and safety of introducing GM organisms for public services?
(a) Genetic Engineering Approval Committee
(b) Research Committee on Genetic Manipulation
(c) Bio-safety committee
(d) Indian Council of Agricultural Research

Answer: A

UNIT IX - BIOTECHNOLOGY

• A newspaper has reported that an American company has patented turmeric. Indian government is fighting against this patent. What will you call this act of American company?
Ans.• Biopiracy.

Values
• Awareness 
• Justice for country.

• Sangeeta has developed a transgenic crop. She wants to grow this crop directly into the field. Will you allow her to do so? What will you suggest her?
Answer : Insulin can also be synthesized in laboratory with r DNA

Values
• Empathy.
• Awareness 
• Concern.

• Arvind s mother has developed Diabetes. Doctor suggests her to take Insulin injections. But his mother declines as she presumes injections are prepared by slaughtering of animals .How will you solve his mother’s problem with your knowledge of biotechnology?

Answer : No, as GMO may pose some threat to environment or living organism I will ask her to approach GEAC.

Values
• Sense of responsibility. 
• Understanding.

• Inspector Dubey could find only few hair strands from crime scene. He wants to proceed for DNA fingerprinting but the amount of DNA is very less. In your opinion what could be the solution to this problem? Write the basic steps of this technique?

Answer : He can amplify DNA with the help of PCR technique Basic steps of PCR ----
• Denaturation
• Annealing
III) Extension

Values
• Critical thinking 
• Awareness.

• Sunil’s uncle is very worried as his crop is destroyed by insects. He suggests his uncle to use Bt crops. His uncle says that such crops produce toxins which can harm the consumers of this crop. Whom do you support and why

Answer : I support him.

Bt crops produce protoxin which changes into active form only in the intestine of insects in alkaline pH. It is completely safe for other animals and human beings

Values
• Empathy.
• Awareness.
More Questions

Q.1 A newspaper has reported that an American company has patented turmeric. Indian government is fighting against this patent. What will you call this act of American company?
• Biopiracy.

Values
• Awareness
 • Justice for country.

Q.2 Sangeeta has developed a transgenic crop. She wants to grow this crop directly into the field. Will you allow her to do so? What will you suggest her?

• Insulin can also be synthesized in laboratory with r DNA

Values
• Empathy.
• Awareness
• Concern.

Q.3 Arvind s mother has developed Diabetes. Doctor suggests her to take Insulin injections. But his mother declines as she presumes injections are prepared by slaughtering of animals .How will you solve his mother’s problem with your knowledge of biotechnology?

• No, as GMO may pose some threat to environment or living organism

I will ask her to approach GEAC.

Values
• Sense of responsibility.
• Understanding.

Q.4 Inspector Dubey could find only few hair strands from crime scene. He wants to proceed for DNA fingerprinting but the amount of DNA is very less. In your opinion what could be the solution to this problem? Write the basic steps of this technique?

• He can amplify DNA with the help of PCR technique Basic steps of PCR ----
• Denaturation
• Annealing
III) Extension

Values
• Critical thinking
• Awareness.

Q.5 Sunil’s uncle is very worried as his crop is destroyed by insects. He suggests his uncle to use Bt crops. His uncle says that such crops produce toxins which can harm the consumers of this crop. Whom do you support and why?

• I support him.

Bt crops produce protoxin which changes into active form only in the intestine of insects in alkaline pH. It is completely safe for other animals and human beings

Values
• Empathy.
• Awareness.