Biotechnology and its Application Exam Questions Class 12 Biology

Please see Chapter 12 Biotechnology and its Application Exam Questions Class 12 Biology below. These important questions with solutions have been prepared based on the latest examination guidelines and syllabus issued by CBSE, NCERT, and KVS. We have provided Class 12 Biology Questions and answers for all chapters in your NCERT Book for Class 12 Biology. These solved problems for Biotechnology and its Application in Class 12 Biology will help you to score more marks in upcoming examinations.

Exam Questions Chapter 12 Biotechnology and its Application Class 12 Biology

Objective Type Questions

Question. Bacillus thuringiensis (Bt) strains have been used for designing novel
(a) bio-fertilizers
(b) bio-metallurgical techniques
(c) bio-mineralization processes
(d) bio-insecticidal plants

Question. Bt toxin kill the larvae of certain insects
(a) by binding of activated toxin on mid gut epithelial cells, creating pores, leading to swelling and lysis.
(b) by stopping transcription of larval cells.
(c) by altering central dogma taking place in the cells of gut of larva.
(d) by stopping protein synthesis.

Question. Cry-genes have been introduced in
(a) cotton and corn
(b) rice
(c) potato and soyabean
(d) all of the above

Question. RNA interference (RNAi) technique has been devised to protect the plants from nematode is silenced by ______ produced by the host plant.
(a) dsDNA
(b) ssDNA
(c) dsRNA
(d) target proteins

Question. C-peptide of human insulin is
(a) a part of mature insulin molecule.
(b) responsible for formation of disulphide bridges.
(c) removed during maturation of pro-insulin to insulin.
(d) responsible for its biological activity.

Question. E. coli are used in production of
(a) rifampicin
(b) LH
(c) ecdysone
(d) interferon

Question. In some children, ADA deficiency can be cured by
(a) bone marrow transplantation
(b) enzyme replacement therapy
(c) both (a) and (b)
(d) none of the above

Question. Genes of interest can be selected from a genomic library by using
(a) restriction enzymes
(b) cloning vectors
(c) DNA probes
(d) gene targets

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

Question. The protein a-1 antitrypsin is used to treat the
(a) cancer
(b) rheumatoid arthritis
(c) Alzheimer’s disease
(d) emphysema

Question. GEAC stands for
(a) Genome Engineering Action Committee
(b) Ground Environment Action Committee
(c) Genetic Engineering Approval Committee
(d) Genetic and Environment Approval Committee

Question. Which variety of rice was patented by a U.S. company even though the highest number of varieties of this rice is found in India ?
(a) Sharbati Sonara
(b) Co-667
(c) Basmati
(d) Lerma Roja

Question. The use of bioresources by multinational companies and other organizations without proper authorisation from the countries and people concerned without compensatory payment is called
(a) bioethics
(b) biopiracy
(c) bioterror
(d) bioweapon

Statement Type Questions

Question. Which of the following statement is correct about Bt toxin ?
(a) Bt protein exists as active toxin in the Bacillus.
(b) The activated toxin enters the ovaries of the pest to sterilize it and thus prevent its multiplication.
(c) The concerned Bacillus has antitoxins.
(d) The inactive protoxin gets converted into active form in the insect gut.

Question. Which one of the following statement(s) is/are correct about Genetic Engineering Approval committee (GEAC) ?
(a) It will make decision regarding the validity of GM research.
(b) It will make the safety of introducing GM – organism for public services.
(c) Its genetic modification of organism can have unpredictable results when such organisms are introduced into the ecosystem. Therefore, the Indian government has set up organisation such as GEAC.
(d) All of the above

Question. Which of the following is a correct statement?
(a) “Bt” in Bt-cotton indicates that it is genetically modified organism produced through biotechnology.
(b) Somatic hybridization involves fusion of two complete plant cells carrying desired genes.
(c) The anticoagulant hirudin is being produced from transgenic Brassica napus seeds.
(d) “Flavr Savr” variety of tomato has enriched the production of ethylene which improves its taste.

Question. Which of the following statements is correct?
(a) The current interest in the manipulation of microbes, plants and animal has raised serious ethical issues.
(b) One possible risk of genetic engineering is the accidental production of dangerously resistant microorganisms.
(c) Although risks are possible, genetic engineering appears to offer more of contribution to human welfare than threats.
(d) All of the above

Question. Which of the following statements (i – v) is/are incorrect ?
(i) Recombinant DNA technology is used to improve crop plants by increasing their productivity, by making them more nutritious and by developing disease resistant.
(ii) Bt cotton is resistant to bollworm infestation.
(iii) Bacillus thuringiensis can form cry protein during any phase of their growth.
(iv) Bacillus thuringiensis is not harmed by self cry protein because of its occurrence as protoxin (inactive).
(v) Protoxin cry protein is changed into active cry protein in the stomach of insects due to alkaline pH in stomach.
(a) Only (iii)
(b) (i) and (iv)
(c) All of these
(d) None of these

Question. Read the following statements and choose the correct statements.
(i) Gene therapy has been tested on a large number of patients with a wider variety of inherited genetic disorders, and in numerous cases it has produced a complete cure.
(ii) Genetic engineering has been used to produce insulin for curing the diabetes.
(iii) DNA hybridization is the base pairing of DNA from two different sources.
(iv) Genetic engineering is a technique of plant breeding.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i), (ii) and (iii)
(d) All of these

Question. Transgenic animals are produced
(i) to study how genes are regulated and how they affect the normal functions of body and its development.
(ii) to study diseases.
(iii) to obtain useful biological products .
(iv) to test vaccine safety and chemical safety.
(a) (i), (ii), (iii) and (iv)
(b) (i) and (iv)
(c) (ii) and (iv)
(d) Only (i)

Question. The given statements are the steps in one type of genetherapy.
(i) Inject engineered cells into patients bone marrow.
(ii) Viral DNA carring the normal allele inserts into chromosome.
(iii) Let retrovirus infect bone marrow cells that have removed from patient and cultured.
(iv) Insert RNA version of normal allele into retrovirus.
The correct sequence is
(a) (i), (ii), (iii) and (iv)
(b) (iv), (iii), (ii) and (i)
(c) (i), (ii), (iv) and (iii)
(d) (iv), (iii), (i) and (ii)

Assertion/Reason Type Questions

In the following questions, a statement of Assertion is followed by a statement of Reason.
(a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
(b) If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
(c) If Assertion is true but Reason is false.
(d) If both Assertion and Reason are false.

Question. Assertion : An application of tissue culture is the production of transgenic plants.
Reason : A transgenic organism is one that contains and expresses a transgene.

Question. Assertion : ELISA is based on the principle of antigen antibody interaction.
Reason : Pathogen infection is usually detected by presence of antigens or detection of antibodies
synthesized against the pathogen.

Matching Type Questions

Question. Match the following and choose the correct combination from the options given below :

Column – I	Column – II
A. Escherichia coli	I. nif gene
B. Bacillus thuringiensis	II. Interferon
C. Rhizobium meliloti	III. Bt toxin
D. Agrobacterium tumefaciens	IV. Vector

(a) A – II; B – I; C – (IV); D – III
(b) A – II; B – I; C – (III); D – IV
(c) A – II; B – III; C – I; D – IV
(d) A – IV; B – I; C – II; D – III

Question. Match column-I with column-II and identify the correct option.

Column – I	Column – II
A. Gene therapy	I. Rhizobium
B. Biofertilizer	II. Cry gene
C. Bt cotton	III. SCID
D. Humulin	IV. Diabetes

(a) A – II; B – I; C – IV; D – III
(b) A – III; B – I; C – II; D – IV
(c) A – II; B – III; C – I; D – IV
(d) A – IV; B – I; C – II; D – III

Question. Match column-I with column-II and choose the correct option.

Column – I	Column – II
A. Forensic science	I. AIDS
B. ELISA	II. Radioactive DNA/RNA
C. Probe	III. Emphysema
D. a-1-antitrypsin	IV. DNA fingerprinting

(a) A – II; B – I; C – IV; D – III
(b) A – II; B – I; C – III; D – IV
(c) A – II; B – III; C – I; D – IV
(d) A – IV; B – I; C – II; D – III

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. 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. 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. 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. 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)

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. 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. (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. 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.

Long Answer Questions

Question. (a) List any four beneficial effects of GM plants.
(b) Explain how has Bacillus thuringiensis contributed in developing resistance to cotton bollworms in cotton plants. 
Answer. (a) (i) Increases tolerance against abiotic stresses (cold, drought, salt, heat).
(ii) Reduces reliance on chemical pesticides (pest-resistant crops).
(iii) Reduces post-harvest losses.
(iv) Increases efficiency of minerals used by plants (this prevents early exhaustion of fertility of soil).
(v) Enhances nutritional value of food, e.g., vitamin ‘A’ enriched rice (golden rice). (Any four)
(b) Bt cotton
• Some strains of Bacillus thuringiensis produce proteins that kill some insects like lepidopterans (tobacco budworm,armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).
• B. thuringiensis forms protein crystals which contain a toxic insecticidal protein.
• Bt toxins are initially inactive protoxins but after ingestion by the insect their inactive toxin becomes active due to the alkaline pH of the gut, which solublises the crystals.

Question. Name the process involved in the production of nematode-resistant tobacco plants, using genetic engineering. Explain the strategy adopted to develop such plants. 
Answer. The process involved in the production of nematode-resistant plants is RNA interference or RNAi.
Using Agrobacterium vectors, nematode-specific genes were introduced into the host plant. The introduction of DNA was such that it produced both sense and antisense RNA in the host cells.

These two RNA’s being complementary to each other formed a double stranded RNA (dsRNA) that initiated RNAi and thus, silenced the specific mRNA of the nematode. The consequence was that the parasite could not survive in a transgenic host expressing specific interfering RNA. The transgenic plant, therefore, got itself protected from the parasite.

Question. How did the process of RNA interference help to control the nematode from infecting roots of tobacco plants? Explain. 
Answer. Using Agrobacterium vectors, nematode specific genes are introduced into host plant. The introduction of DNA produced both sense and anti sense RNA in host cells. These two RNA’s being complementary formed a double stranded RNA (dsRNA) that initiated RNAi and silenced the specific mRNA of the nematode. As a result, the parasite could not survive in the transgenic host expressing specific interfering RNA.

Question. (a) How do organic farmers control pests? Give two examples.
(b) State the difference in their approach from that of conventional pest control methods.
Answer. (a) By natural predation or biological control.
Examples: Lady bird used to kill aphids, dragon flies used to kill mosquitoes, Bacillus thuringiensis used to kill cotton bollworm.
(b) (table 450)

Question. Name the host plant and the part that Meloidogyne incognita infects. Explain the role of Agrobacterium in production of dsRNA in host plant. 
Answer. Meloidogyne incognita infects the roots of tobacco plant.
For role of Agrobacterium, Pest resistant plants
• A nematode Meloidogyne incognita infects the roots of tobacco plants which reduces the production of tobacco.
• It can be prevented by using RNA interference (RNAi) process which is checked by silencing of specific mRNA due to a complementary dsRNA.
• dsRNA binds and prevents translation of the mRNA (silencing).
• The source of this dsRNA could be from an infection by viruses having RNA genomes or mobile genetic elements (transposons) which replicate through an RNA intermediate.

Question. Gene expression can be controlled with the help of RNA molecule. Explain the method with an example. 
Answer. Gene expression can be controlled by using RNA molecule and this technology is called RNA interference or RNAi. It is used to block the expression of certain genes and also referred to as gene silencing. During this process, RNA complementary to mRNA being produced by the gene, is introduced into the cell. This RNA binds to the mRNA making it double stranded and therefore stops its translation. Resistance to nematode Meloidogyne incognita in tobacco has been achieved by this method.

Question. Explain the synthesis of genetically engineered human insulin.
Answer. Genetically engineered insulin
• Insulin contains two short polypeptide chains—chain A and chain B linked by disulphide bridges.
• In mammals, insulin is synthesised as a pro-hormone (that needs to be processed to become mature and functional hormone). It contains an extra stretch called C peptide.
• C peptide is absent in mature insulin and is removed during maturation into insulin.

Question. Why do lepidopterans die when they feed on Bt cotton plant? Explain how does it happen.
Answer. Bt cotton contains inactive toxin protein or protoxin. These are insecticidal proteins in the form of crystal protein. Once the insect ingests its, the inactive protoxin is converted into active form due to alkaline pH in the gut, which solubilise the crystals. The activated toxins bind to the surface of midgut epithelial cells, thus creating pores which causes cell swelling and lysis, eventually leading to the death of the insect pest.