We have given these Class 12 Biology Important Questions Chapter 12 Biotechnology and its Applications to solve different types of questions in the exam. Go through these Class 12 Biology Chapter 12 Important Questions, Biotechnology and its Applications Important Questions & Previous Year Questions to score good marks in the board examination.
Question 1.
Write the two specific ‘cry’ genes that encode the proteins which control cotton boll worms. (All India 2019)
Answer:
cry IAc and cry IIAb control cotton bollworm and cry I Ab controls corn borer.
Question 2.
Mention the chemical change that proinsulin undergoes, to be able to act as mature insulin. (2018)
Answer:
The C-peptide present in proinsulin is removed during its maturation.
Question 3.
What are cry genes? In which organisms are they present? (All India 2017)
Answer:
‘cry genes’ are genes found in Bacillus thuringiensis, a bacterium. These genes encode for protein crystals that contain a toxic insecticidal protein called Bt toxin.
Question 4.
Suggest any two possible treatments that can be given to patient exhibiting adenosine deaminase deficiency. (Delhi 2015)
Or
A boy has been diagnosed with ADA (Adenosine Deaminase) deficiency.
I Suggest any one possible treatment. (Delhi 2014C)
Answer:
Question 5.
Why do children cured by enzyme replacement therapy for adenosine deaminase deficiency need periodic treatment? (All India 2015)
Answer:
Children cured by enzyme replacement therapy for adenosine deaminase deficiency need periodic treatment because in such type of treatment genetically engineered lymphocytes are used and these cells are mortal.
Question 6.
State the role of C-peptide in human insulin. (All India 2014)
Answer:
The C-peptide is an extra stretch of the peptides that connect the A and B-polypeptide chains of insulin in prohormone. During processing to release mature and functional insulin, this C-peptide is removed.
Question 7.
Write the possible source of RNA interference (RNAi) gene. (Delhi 2013C)
Or
State the role of transposons in silencing of mRNA in eukaryotic cells. (All India 2012)
Answer:
Mobile genetic elements, i.e. transposons are the possible source of RNA interference (RNAi) gene which is further involved in the silencing of the specific mftNA and prevents translation.
Question 8.
Name any two techniques that serve the purpose of early diagnosis of some bacterial/viral human diseases. (Foreign 2011)
Or
Name a molecular diagnostic technique to detect the presence of a pathogen in its early stage of infection. (Delhi 2010)
Answer:
Techniques that serve the purpose of early diagnosis of some bacterial/viral human diseases are as follows
Question 9.
How does dsRNA gain entry into eukaryotic cell to cause RNA interference? (Delhi 2011C)
Answer:
dsRNA gains entry into eukaryotic cell either through
Question 10.
Name the source organism of the gene cry IAc and its target pest. (Foreign 2011)
Answer:
Source of gene cry IAc is Bacillus thuringiensis and its target pest is cotton bollworm.
Question 11.
Name the source used to produce hapatitis-B vaccine using rDNA technology. (Delhi 2015C)
Answer:
The source of hepatitis-B vaccine is yeast. Recombinant DNA technology has allowed the production of antigenic polypeptides of pathogen in bacteria or yeast. Vaccines produced using this approach allow large scale production and hence greater availability for immunisation.
Question 12.
Write the functions of
(i) cry IAc gene
(ii) RNA interference (RNAi) (Outside Delhi 2015C)
Answer:
(i) cry IAc codes for toxic insecticidal protein as inactive protoxins in Bacillus thuringiensis. This toxin kills the cotton bollworm.
(ii) RNA interference is associated with silencing of specific ntRNA and is a method of cellular defence in eukaryotes.
Question 13.
What is gene therapy? Name the first clinical case in which it was used. (Delhi 2014)
Or
Name the disease that was first to get the gene therapy treatment. Write the cause of the disease and the effect it has on the patient. (Delhi 2014C, 2013)
Answer:
Gene therapy is a corrective therapy or technique of genetic engineering that is used to replace a faulty or non-functional gene with a normal healthy functional gene.
The first clinical gene therapy was given to a 4 year old girl with ADA (Adenosine Deaminase) deficiency in 1990. It is caused due to the deletion of the gene coding for ADA, which adversely . affects the functioning of imnune system.
Question 14.
Why does Bt toxin not kill the bacterium that produces it, but kills the insect that ingests it? (Delhi 2014)
Or
Why do the toxic insecticidal proteins secreted by Bacillus thuringiensis kill the insect and not the bacteria itself? (Foreign 2010)
Answer:
Bt toxin does not kill bacteria because in bacteria it exists in inactive state.
When Bt toxin is ingested by an insect, it gets converted into its active form due to the alkaline pH of the gut.
The activated toxin binds to the surface of the epithelial cells of the midgut and creates pores. Water enters through these pores and causes swelling and lysis of cells in insect body.
Question 15.
Explain how Eli Lilly, an American company, produced insulin by recombinant DNA technology. (Foreign 2014)
Answer:
Steps involved in insulin production by Eli Lilly company are as follows
Question 16.
What do ‘cry genes’ in Bacillus thuringiensis code for? State its importance for cotton crop. (All India 2014C)
Or
Name the soil bacterium that produces a protein/chemical that is toxic to insect pests. Show with example that these are encoded by different forms of the genes. (All India 2012)
Answer:
‘cry genes’ in Bacillus thuringiensis code for toxic insecticidal proteins called Cry proteins which are encoded by different forms of a gene called cry gene, e.g. cry IAc and cry II Ab control the cotton bollworm whereas cry IAb controls corn borer.
Cry proteins when expressed in cotton crops through genetic engineering confer pest resistance against cotton bollworms and prevent damage. As the larva of these insects when feed upon cotton plant parts, the toxin gets activated in their gut, lysing their cells and leads to death thus, making them pest resistant.
Question 17.
Human insulin when synthesised in the body needs to be processed before it can act. Explain giving reasons. (Delhi 2014C)
Or
Why is proinsulin so called? How is proinsulin different from functional insulin in humans? (All India 2013, 2012C)
Answer:
Human insulin when initially synthesised in human body consists of three peptide chains-A, B and C. The C-peptide is an extra stretch of amino acids joining the A and B-chains. This is called proinsulin or prohormone. It undergoes processing or splicing to release the functional mature insulin that can carry out its normal functions.
During processing, the C-peptide is removed. Only A and B-chains contribute to form the functional insulin.
Question 18.
Write any two ways how genetically modified plants are found to be useful? (All India 2014C)
Answer:
The genetically modified plants are found to be useful as they
Question 19.
(i) State the role of DNA ligase in biotechnology.
(ii) What happens when Meloidogyne incognita consumes cells with RNAi gene? (Delhi 2012)
Answer:
(i) DNA ligase enzyme is used to join two DNA fragments from their ends.
(ii) When Meloidogyne incognita (parasite) consumes cells with RNA/ gene, parasite cannot survive and the infection is prevented. It is mainly because introduced DNA forms both sense and anti-sense RNA. These two strands being complementary to each other form dsRNA. This dsRNA binds and prevents translation of nematode OTRNA. Thus, the wRNA of nematode is silenced and the parasite cannot survive there. This produces Meloidogyne incognita resistant tobacco plants.
Question 20.
(i) Mention the cause and the body system affected by ADA deficiency in humans.
(ii) Name the vector used for transferring ADA-DNA into the recipient cells in humans. Name the recipient cells. (All India 2012)
Answer:
(i) For ADA deficiency, Refer to Answer No. 13.
(ii) Retroviral vector is used to transfer ADA-DNA into the recipient cells of human, i.e. lymphocytes.
Question 21.
How does ‘RNA interference’ take place in eukaryotes? Mention its importance. (Delhi 2012C)
Or
Explain the process of RNA interference. (Delhi 2011)
Answer:
The strategy to prevent nematode infestation in tobacco plant is RNA interference.
It involves silencing of a specific mRNA due to a complementary dsRNA which binds and prevents translation.
Question 22.
Explain how a hereditary disease can be corrected. Give an example of the first successful attempt made towards correction of such disease. (Delhi 2011)
Answer:
Hereditary disease can be corrected by gene therapy. It is a collection of methods that allow correction or replacement of defective genes. The first gene therapy was given in 1990 to a 4 year old girl with Adenosine Deaminase (ADA) deficiency. It is caused due to the deletion of gene for adenosine deaminase.
The treatment involves following steps
Question 23.
How does recombinant DNA technology help in detecting the presence of mutant gene in cancer patients? (All India 2o11c)
Answer:
A single-stranded DNA or RNA, tagged with a radioactive molecule (probe) is allowed to hybridise with its complementary DNA in a clone of cells followed by detection using
autoradiography. The clone having the mutated gene will not appear on photographic film, because probe will not be complementary with mutated gene thus, helpful in defecting the presence of mutated gene in cancer patients.
Question 24.
Why is the introduction of genetically engineered lymphocytes into an ADA deficiency patient not a permanent cure? Suggest a possible permanent cure. (Delhi 2010)
Answer:
The genetically engineered lymphocytes have a definite lifespan. Hence, the patient requires periodic infusion of genetically engineered lymphocytes, so the cure is not permanent. The cure can be permanent, if the gene isolated from marrow cells producing ADA is introduced into the cells at early embryonic stages.
Question 25.
How did Eli Lilly synthesise the human insulin? Mention one difference between this insulin and the one produced by the human pancreas. (All india 2010)
Answer:
(i) For insulin synthesis, Refer to Answer No. 15.
(ii) Differences between insulin produced by rDNA and insulin produced by human pancreas are as follows
Insulin produced by rDNA | Insulin produced by human pancreas |
It has A and B-polypeptides. | It has three polypeptides. A, B and C-chains before maturing, called the prohormone. |
It directly synthesises mature hormone. | It undergoes processing to form mature and functional hormone. |
Question 26.
How is Bt cotton made to attain resistance against bollworm? (Delhi 2010C)
Answer:
Bt toxin genes cry IAc and cry IIAb control cotton bollworms. These genes are isolated from the bacterium and are incorporated into cotton plants. For action of Bt toxin, Refer to Answer No. 14 for methodology.
Question 27.
How has the use of Agrobacterium as vectors helped in controlling Meloidogyne incognita infestation in tobacco plants? Explain in correct sequence. (2018)
Answer:
Several nematodes infect a wide variety of plants and animals including human beings.
A nematode Meloidogyne incognita infects the roots of tobacco plants which reduces the production of tobacco.
The strategy adopted to prevent this infection is based on the process of RNA interference (RNAi). RNA; mechanism takes place in all eukaryotic organisms as a method of cellular defence.
This method involves the following steps
Question 28.
Explain the various steps involved in the production of artificial insulin. (All India 2017)
Or
Recombinant DNA technology is of great importance in the field of medicine. With the help of a flow chart, show how this technology has been used in preparing genetically engineered human insulins. (Delhi 2015)
Answer:
An American company Eli Lilly produced insulin via recombinant DNA technology in 1983.
Insulin production by using recombinant DNA technology is shown in flow chart below
Question 29.
Why do lepidopterans die when they feed on Bt cotton plant? Explain how does it happen. (Delhi 2017)
Or
Explain the application of rDNA technology to produce insulin. (Delhi 2015C)
Answer:
Bt cotton plants are the transgenic plants that express a Bacillus thuringiensis gene called cry gene. This gene, encodes for protein crystals having insecticidal properties against insects of group Lepidoptera, Diptera and Coleoptera. Inside the bacterium, these proteins remain inactive and do not harm the bacteria. However, these inactive crystals can get activated in the alkaline pH of the gut of insects upon ingestion.
After activation, these crystals can bind to the receptors present on the membranes of gut epithelial cells. Due to this binding, the membrane swells and pores are created on them. These pores lead to bursting of cell and soon the lepidopteran dies due to starvation.
Question 30.
Explain how Eli Lilly, an American company produced insulin by recombinant DNA technology. (2018)
Answer:
For DNA technology for insulin production, Refer to Answer No. 28.
Question 31.
What is GMO? List any five possible advantages of a GMO to a farmer. (All India 2018)
Answer:
The plants, bacteria, fungi and animals whose
genes have been altered are called Genetically Modified Organisms (GMOs). GM plants are useful in many ways.
Genetic modification has done the following changes to the phenotypic expression of the plants,
Question 32.
How has the study of biotechnology helped in developing pest-resistant cotton crop? Explain. (Delhi 2016C)
Or
One of the major contributions of biotechnology is to develop pest-resistant varieties of cotton plants. Explain how it has been made possible. (Foreign 2015)
Or
Name the pest that destroys the cotton bolls. Explain the role of Bacillus thuringiensis in protecting the cotton crop against the pest to increase the yield. (All India 2013)
Or
How is the Bt cotton plant created as a GM plant? How is it protected against bollworm infestation? (Delhi 2013C)
Or
Name the genes responsible for making Bt cotton plants resistant to bollworm attack. How do such plants attain resistance against bollworm attacks? Explain. (Delhi 2012)
Answer:
Biotechnology had hepled in generating plant varieties against the pests that destroy the cotton balls, i.e. cotton bollworms and cotton borer.
Bt cotton is created by using some strains of a bacterium. Bacillus thuringiensis (Bt is short form).
Question 33.
Why is molecular diagnosis preferred over conventional methods? Name any two techniques giving one use of each. (Delhi 2016C)
Answer:
Using conventional methods of diagnosis (serum and urine analysis), early detection of diseases is not possible. To overcome this problem, some molecular diagnosis techniques were developed that provide early detection of diseases. These are as follows
(i) Polymerase Chain Reaction (PCR) helps in early detection of diseases or pathogens by the amplification of their nucleic acid.
PCR can amplify nucleic acids of pathogens even when their concentration is very low.
This technique can be used for detecting HIV in suspected AIDS patients, genetic mutations in suspected cancer patients and in identifying genetic disorders.
(ii) Enzyme Linked Immunosorbent Assay (ELISA) is based on the principle of antigen-antibody interaction. Infection by pathogen can be detected by the presence of antigens (proteins, glycoproteins, etc.) or by detecting the antibodies synthesised against the pathogen.
Question 34.
How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidogync incognita? (Delhi 2016)
Or
How did the process of RNA interference help to control the nematode from infecting the roots of tobacco plants. (Foreign 2014)
Answer:
A nematode Meloidogyne incognita infects the roots of tobacco plants, which reduces the production of tobacco. The strategy adopted to prevent this infection is based on the process of RNA interference (RNAf). RNAi takes place in all eukaryotic organisms as a method of cellular defence. This method involves silencing of a specific mRNA due to complementary rfsRNA molecule that binds to and prevents translation of mRNA.
Thus, resulting into the death of the nematode.
Refer to Answer No. 19 (ii) for methodology.
Question 35.
Explain enzyme replacement therapy to treat adenosine deaminase deficiency. Mention two disadvantages of this procedure. (All India 2016)
Answer:
In enzyme replacement therapy, the patient is given functional ADA (Adenosine Deaminase) by injection.
Refer to Answer No. 22 for methodology.
Disadvantages
Question 36.
People are quite apprehensive to use GM crops. Give three arguments in support of GM crops so as to convince the people in favour of such crops. (Outside Delhi 2016C)
Answer:
The GMOs are the plants, animals, bacteria, etc. whose genes have been altered by genetic manipulation. They were created because
Advantages of GMOs are as follows
Question 37.
Mention the cause of ADA deficiency in humans. How has genetic engineering helped patients suffering from it? (Outside Delhi 2015C)
Or
(i) Explain the effect of deletion of the gene for ADA in an individual.
(ii) How does the gene therapy help in this case? (All India 2010C)
Answer:
(i) Deletion of the gene for ADA in an individual leads to ADA deficiency disorder. Adenosine Deaminase (ADA) enzyme is crucial for immune system to function.
(ii) Gene therapy is helpful in the treatment of ADA deficiency.
Refer to Answer No. 22 for methodology.
Question 38.
Describe any three potential applications of genetically modified plants. (All India 2015)
Answer:
Potential applications of genetically modified plants are
Question 39.
Name the host plant and its part that Meloidogyne incognita infects. Explain the role of Agrobacterium in the production of dsRNA in the host plant. (Delhi 2014C)
Answer:
The nematode Meloidogyne incognita infects the roots of tobacco plants.
The Agrobacterium is used as vectors carrying nematode specific genes to be introduced in host plant. These genes when expressed inside host plant produce sense and anti-sense RNA strands, complementary to nematode’s functional mRNA. This binding results in the formation of double-stranded RNA and inhibiting or silencing the translation of RNA specified. This process is called RNA interference.
Question 40.
(i) Tobacco plants are damaged severely when infested with Meloidogyne incognita. Name and explain the strategy that is adopted to stop this infestation.
(ii) Naipe the vector used for introducing the nematode specific gene in tobacco plant. (All India 2012)
Or
How does RNA interference help in developing resistance in tobacco plant against nematode infection? (Delhi 2010)
Answer:
Question 41.
(i) How has biotechnology helped in producing Meloidogyne incognita resistant tobacco plant?
(ii) Why does this nematode die on eating such a GM plant? (Delhi 2010C)
Answer:
(i) For developing Meloidogyne incognita resistant tobacco plant, Refer to Answer No. 34.
(ii) Due to the RNAi process, specific mRNA of nematode is silenced. The result is that the parasite could not survive after eating such GM or transgenic plant (host), expressing, v specific interfering RNA.
Question 42.
Explain the application of biotechnology in producing Bt cotton. (Delhi 2014)
Answer:
For the use of Biotechnology to develop St cotton, Refer to Answer No. 32.
Question 43.
(i) Name the source from which insulin was extracted earlier. Why is this insulin no more in use by diabetic people?
(ii) Explain the process of synthesis of insulin by Eli Lilly company. Name the technique used by the company.
(iii) How is the insulin produced by human body different from the insulin produced by the above mentioned company? (All India 2011)
Answer:
(i) Insulin was extracted earlier from pancreas of slaughtered pigs and cattle animals. Insulin obtained from these sources caused some allergy or some other reactions to the foreign protein.
(ii) For production of human insulin by Eli Lilly company. Refer to Answer No. 28.
(iii) For different insulin produced by pancreas and by using rDNA technology, Refer to Answer No. 25 (ii).
Question 44.
What is biopiracy? (Delhi 2017)
Answer:
Biopiracy refers to the use of bioresources by multinational companies and other organisations without proper authorisation from people and countries concerned.
Question 45.
What are transgenic animals? Give an example. (All India 2016)
Answer:
Animals with manipulated DNA to possess and express the characters of an extra (foreign) gene are known as transgenic animals, e.g. transgenic
rats, rabbits, pigs, etc.
Question 46.
Mention two objectives of setting up GEAC by our government. (All India 2015)
Answer:
GEAC is an organisation setup by the Indian government to make decisions pertaining with genetic research and experiments. The two objectives of setting up Genetic Engineering Approval Committee (GEAC) by the Indian Government are
Question 47.
What is biopiracy? State the initiative taken by the Indian Parliament against it. (Delhi 2014)
Answer:
For biopiracy, Refer to Answer No. 1.
The Indian Parliament has cleared a second amendment of Indian Patents Bill as an initiative step against biopiracy. This bill considers issues including patent terms, emergency provisions as well as research and development initiative.
Question 48.
How have transgenic animals proved to be beneficial in
(i) production of biological products?
(ii) chemical safety testing? (Delhi 2014, 2013)
Answer:
(i) The transgenic animals have been proved beneficial in the production of biological products like human protein a-1 antitrypsin (by coding genes for that protein only), for the treatment of emphysema and production of human protein (a-lactalbumin) enriched milk by transgenic cow, i.e. Rosie. This milk was more nutritionally balanced for. human babies than natural cow’s milk.
(ii) Transgenic animals are studied for testing toxicity of drugs and other chemicals, as they carry genes that make them more sensitive to toxic substances.
Question 49.
Mention any four benefits derived from transgenic animals. (Delhi 2012C)
Answer:
Benefits derived from transgenic animals are as follows
Question 50.
How is ‘Rosie’ considered different from a normal cow? Explain. (All India 2011; Foreign 2010)
Answer:
The transgenic cow Rosie, produced human protein-enriched milk (2.4 gm/L). It contained the human a-lactalbumin and was nutritionally more balanced for human babies than natural cow’s milk.
Question 51.
(i) What are transgenic animals ?
(ii) Name the transgenic animal having the largest number amongst all the existing transgenic animals.
(iii) Mention any three purposes for which these animals are produced. (2018 C)
Answer:
(i) Transgenic animals Refer to text on page no. 310.
(ii) Transgenic mice have the largest number (over 95%) amongst all the existing transgenic animals.
(iii) For purpose of producing transgenic animals.
Refer to text on page no. 310.
Question 52.
Biopiracy should be prevented. State why and how. (All India 2011)
Answer:
Biopiracy should be prevented because
Question 53.
Aditya’s father requested to the farmer’s in his village to stop using chemical fertilisers in crop fields. Was he correct? Give reason.
Answer:
Yes, agrochemicals like fertilisers and pesticides have harmful effects on the health of living beings and the environment.
Question 54.
A group of activists was protesting without violence against the release of a GMO in the market, stating that production of GMO is an unethical practice.
(i) What is meant by GMO? Can the production of GMOs be considered unethical? Give reason.
(ii) What values do you observe in the activists involved in the protest?
Answer:
(i) GMO refers to Genetically Modified Organism. Yes, manipulation of living organism without showing concern about them is considered unethical.
(ii) Value observed is concern towards animal safety.
Question 55.
Anil’s father is suffering from high blood sugar. Doctors had advised regular insulin injections, which were declined by the family due to objections on the process used in insulin production. The doctor explained the process now used in insulin production and its advantages.
(i) Why did the family declined the use of insulin injection despite its necessity ?
(ii) Name the process by which insulin is produced now-a-days and the organism involved.
(iii) What values are shown by the doctor?
Answer:
(i) Earlier the insulin was produced by slaughtering of animals like pigs. They also cause allergic reactions in patients. The family declined because they were against such process and products.
(ii) The process is recombinant DNA technology and organism used is E.coli.
(iii) The doctor is responsible, aware of recent developments in science and honest towards his duty.