NCERT Exemplar for Class 12 Biology Chapter-12 (Book Solutions)

Multiple Choice Questions

1. Bt cotton is not

(a) A GM plant

(b) Insect resistant

(c) A bacterial gene expressing system

(d) Resistant to all pesticides

Ans: Option (d) Bt cotton is a GM plant, insect resistant, and a bacterial gene expressing system. It is not resistant to all pesticides.

2. C-peptide of human insulin is

(a) A part of a 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.

Ans: Option- (c). C-peptide of human insulin is removed during maturation of pro-insulin to insulin.

3. GEAC stands for

(a) Genome Engineering Action Committee

(b) Ground Environment Action Committee

(c) Genetic Engineering Approval Committee.

(d) Genetic and Environment Approval Committee

Ans: Option (c) GEAC stands for Genetic Engineering Approval Committee. This organization was established by the Indian government to make choices about the validity of GM research and the safety of incorporating GM organisms into public services.

4. α -1 antitrypsin is

(a) An antacid

(b) An enzyme

(c) Used to treat arthritis

(d) Used to treat emphysema. 

Ans: Option (d) α -1 antitrypsin is used to treat emphysema. Emphysema is one of the diseases that comprise COPD (chronic obstructive pulmonary disease).

5. A probe which is a molecule used to locate specific sequences in a mixture of, DNA or RNA molecules could be

(a) A single-stranded RNA

(b) A single-stranded DNA

(c) Either RNA or DNA

(d) Can be ssDNA but not ssRNA

Ans: Option (c) A single-stranded DNA or RNA, tagged with a radioactive molecule is called a Probe. The probe is marked with a radioactive or chemical tag that enables visualization of its binding. Labeled antibodies are used in a similar way to probe a sample for the presence of a certain protein.

6. Choose the correct option regarding Retrovirus:

(a) An RNA virus that can synthesize DNA during infection

(b) A DNA virus that can synthesize RNA during infection

(c) A ssDNA virus

(d) AdsRNAvirus

Ans: Option (a) Retrovirus is an RNA virus that can synthesize DNA during infection. A retrovirus is a virus that has its genetic material in the form of RNA. When a retrovirus infects a cell, it creates a DNA copy of its genome and inserts it into the host cell's DNA.

7. The site of production of ADA in the body is

(a) Erythrocytes 

(b) Lymphocytes

(c) Blood plasma

(d) Osteocytes

Ans: Option (b) The site of production of ADA in the body is lymphocytes. Lymphocytes are kind of white blood cells present in the bone marrow

8. A protoxin is

(a) A primitive toxin.

(b) A denatured toxin

(c) Toxin produced by protozoa

(d) Inactive toxin

Ans: Option (d) Bt toxin is a protein. Because the Bt toxin protein exists as inactive protoxins, this toxin does not kill Bacillus, but when an insect ingests it, the inactive toxin is changed into an active form of toxin owing to the alkaline pH of the stomach, which solubilizes the crystals.

9. Pathophysiology is the

(a) Study of the physiology of pathogen

(b) Study of the normal physiology of the host

(c) Study of altered physiology of the host

(d) None of the above

Ans: Option (c) Pathophysiology is the study of the altered physiology of the host. As determined by neurophysiologic and imaging tests, pathophysiology involves either cortical or subcortical disease.

10. The trigger for activation of the toxin of Bacillus thuringiensis is

(a) Acidic pH of the stomach

(b) High temperature

(c) Alkaline pH of the gut

(d) Mechanical action in the insect gut

Ans: Option (c) The trigger for activation of-toxin of Bacillus thuringiensis is the alkaline pH of the gut. The Bt toxin proteins exist as inactive protoxins, but when an insect ingests them, the alkaline pH of the alimentary canal converts them to an active form of toxin.

11. Golden rice is

(a) A variety of rice grown along the yellow river in China

(b) Long stored rice having yellow color tint

(c) A transgenic rice having the gene for b-carotene

(d) Wild variety of rice with yellow-colored grains.

Ans: Option (c) Golden rice is transgenic rice having the gene for β-carotene. "Golden Rice" that has been genetically modified can contain up to 35 grams of beta-carotene per gram of rice.

12. In RNAi, genes are silenced using

(a) ss DNA 

(b) ds DNA

(c) dsRNA 

(d) ssRNA

Ans: Option (c) RNAi is a cellular defense mechanism found in all eukaryotic species. This approach includes silencing a specific mRNA by using a complementary dsRNA molecule to attach to the mRNA and prevent it from being translated (silencing).

13. The first clinical gene therapy was done for the treatment of

(a) AIDS 

(b) Cancer

(c) Cystic fibrosis 

(d) SCID (Severe Combined Immuno Deficiency resulting from deficiency of ADA)

Ans: Option (d) A first clinical gene therapy was given in 1990 to a 4-year-old girl with ADA (Adenosine deaminase) deficiency. ADA deficiency causes SCID (Severe Combined ImmunoDeficiency) in which B-lymphocytes and T-lymphocytes are not formed. 

14. ADA is an enzyme that is deficient in a genetic disorder SCID. What is the full form of ADA?

(a) Adenosine deoxy aminase 

(b) Adenosine deaminase

(c) Aspartate deaminase  

(d) Arginine deaminase

Ans: Option (b) ADA stands for Adenosine deaminase. The metabolic disorder adenosine deaminase deficiency (ADA deficiency) causes immunodeficiency. Mutations in the ADA gene are to blame.

15. Silencing of a gene could be achieved through the use of

(a) (RNAi) only 

(b) Antisense RNA only

(c) By both 

(d) None of the above

Ans: Option (c) Silencing of a gene could be achieved through the use of (RNAi) only and Antisense RNA only.

Very Short Answer Type Questions

1. In view of the current food crisis, it is said, that we need another green revolution. Highlight the major limitations of the earlier green revolution.

Ans: Limitations of the green revolution:

1. The Green Revolution tripled food production, yet it was still insufficient to sustain the world's rising population. Improved crop types have contributed to increased yields, but better management methods and the use of agrochemicals have played a larger role (fertilizers and pesticides). Agrochemicals, on the other hand, are sometimes prohibitively expensive for farmers in underdeveloped countries, and traditional breeding cannot provide significant yield gains with existing types.

2. Use of agrochemicals causes eutrophication in aquatic ecosystems and biomagnification in terrestrial ecosystems.

3. Waterlogging and soil salinity are some of the problems of the green revolution.

2. Expand GMO. How is it different from a hybrid?

Ans: GMO stands for Genetically Modified Organism. It differs from a hybrid because, in a hybrid, the cross is done between total genomes of two species or strains, whereas in a GMO, foreign gene(s) is introduced in the organism and is usually maintained as an extra-chromosomal entity or is integrated into the genome of the organism.

3. Differentiate between diagnostics and therapeutics. Give one example and for each category.

Ans: The difference between diagnostic and therapeutic is-

4. Give the full form of ELISA. Which disease can be detected using it? Discuss the principle underlying the test.

Ans: Enzyme-Linked Immuno-sorbent Assay (ELISA) is used for the detection of AIDS. The antigen-antibody interaction concept is based on ELISA. The presence of antigens (proteins, glycoproteins, etc.) or antibodies synthesized against the pathogen can be used to detect pathogen infection.

5. Can a disease be detected before its symptoms appear? Explain the principle involved.

Ans: A pathogen's presence (bacteria, viruses, etc.) is usually suspected only after the infection has caused a disease symptom. The pathogen concentration in the body is already fairly high at this point. Amplification of a bacteria's or virus's nucleic acid by PCR, on the other hand, can detect very low concentrations of bacteria or virus (at a time when the disease's symptoms are not yet obvious).

6. Write a short note on biopiracy highlighting the exploitation of developing countries by the developed countries.

Ans: The word "biopiracy" refers to the use of bio-resources by multinational corporations and other organizations without sufficient permission from the nations and individuals involved, and without remuneration in exchange. The majority of developed countries are wealthy monetarily, yet they lack biodiversity and traditional wisdom. The emerging and undeveloped worlds, on the other hand, are rich in biodiversity and traditional bio-resource knowledge. Traditional bio-resources expertise may be leveraged to generate modern applications as well as to save time, effort, and money throughout the commercialization process.

7. Many proteins are secreted in their inactive form. This is also the hue of many toxic proteins produced by microorganisms. Explain how the mechanism is useful for the organism producing the toxin.

Ans: Many proteins including certain toxins are secreted in their inactive form. They get activated, only when exposed to a specific trigger (pH. temperature etc.). It is advantageous to the bacteria producing it because the bacteria do not get killed due to the action of the protein.

8. While creating genetically modified organisms, genetic barriers are not respected. How can this be dangerous in the long run?

Ans: The human race's manipulation of living organisms cannot carry on indefinitely without regulation. To assess the morality of all human activities that may aid or damage living beings, certain ethical principles are necessary. Beyond the moral implications of such concerns, the biological importance of such issues is equally significant. When creatures that have been genetically modified are put into the ecosystem, the outcomes might be unexpected.

9. Why has the Indian Parliament cleared the second amendment of the country’s patents bill?

Ans: The Indian Parliament has recently cleared the second amendment of the Indian Patents Bill, which take such issues into consideration, including patent terms, emergency provisions, and research and development initiative. Some MNCs or other organizations were found to have received patents on items or services that had previously been part of developing nations' traditional knowledge. By failing to provide proper compensation and/or economic exploitation, this act had the potential to exploit indigenous people. The Indian Parliament approved the second amendment to the country's patent bill to prohibit such abuse of patents.

10. Give any two reasons why the patent on Basmati should not have gone to an American Company.

Ans: The two reasons are: 

(i) Rice is an essential food grain that has been present in Asia's agricultural history for thousands of years. In India alone, there are an estimated 200,000 rice types. India has one of the world's most diverse rice varieties. Basmati rice is distinguished by its particular scent and flavor, and India has 27 known types of Basmati rice.

(ii) There is a reference to Basmati in ancient texts, folklore, and poetry.

11. How was Insulin obtained before the advent of rDNA technology? What were the problems encountered?

Ans: Insulin used for diabetes was earlier extracted from the pancreas of slaughtered cattle and pigs. Insulin from an animal source, though, caused some patients to develop allergies or other types of reactions to the foreign protein.

12. With respect to understanding diseases,’ discuss the importance of transgenic animal models.

Ans: Many transgenic animals are created to help us better understand how genes contribute to disease development. These are designed specifically to act as models for human diseases, allowing researchers to test new therapies for ailments. Many human disorders, including cancer, cystic fibrosis, rheumatoid arthritis, and Alzheimer's, now have transgenic models.

13. Name the first transgenic cow. Which gene was introduced in this cow?

Ans: Rosie was the name of the first transgenic cow. Gene for human alpha-lactalbumin was introduced in its gene, which made the milk nutritionally richer.

14. PCR is a useful tool for the early diagnosis of an infectious disease. Elaborate.

Ans: PCR is a very sensitive technology that allows for the precise amplification of desired DNA using a little number of DNA templates. As a result, it can identify the presence of an infectious organism in a patient who is infected at an early stage (even before the infectious organism has multiplied to a large number).

15. What is GEAC and what are its objectives?

Ans: GEAC (Genetic Energy Approval Committee) is an Indian government organization. Its objective is to:

(a) examine the validity of GM (Genetic modification of organism) research.

(b) inspect the safety of introducing GM for public services.

16. For which variety of Indian rice, the patent was filed by a USA Company?

Ans: Indian Basmati was crossed with a semi-dwarf variety and was claimed as a new variety for which the patent was filed by a USA company.

17. Discuss the advantages of GMO.

Ans: Plants, bacteria, fungi and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO). GM plants have been useful in many ways. Genetic modification has:

• Abiotic stress tolerance was improved in crops (cold, drought, salt, heat).

• Chemical pesticides are used less frequently (pest-resistant crops).

• Aided in the reduction of post-harvest losses.

• Plants' mineral use efficiency has improved (this prevents early exhaustion of fertility of soil).

• Food with a higher nutritional value, such as vitamin 'A' fortified rice.

Short Answer Type Questions

1. Gene expression can be controlled with the help of RNA. Explain the method with an example.

Ans: The RNA molecule can be used to regulate gene expression. RNA interference, or RNAi, is the name of the technique. It's also known as gene silencing since it's used to stop particular genes from expressing. A complementary RNA to the mRNA generated by the gene is delivered into the cell during this step. This RNA attaches to the mRNA and double-strands it, thus stopping translation. This approach has been used to develop tomato resistance to the nematode Meloidogyne incognita.

2. Ignoring our traditional knowledge can prove costly in the area of biological patenting. Justify.

Ans: The majority of industrialized nations are wealthy in terms of money but lack biodiversity and traditional wisdom. The emerging and undeveloped worlds, on the other hand, are rich in biodiversity and traditional bio-resource knowledge. Traditional bio-resources information may be used to produce modern applications, as well as to save time, effort, and money during the commercialization process. There has been an increasing awareness of the unfairness, insufficient reparation, and unequal benefit sharing that exists between industrialized and poor nations. As a result, some countries are enacting legislation to restrict unlicensed use of their bio-resources and traditional knowledge.

3. Highlight any four areas where genetic modification of plants has been useful.

Ans: Plants, bacteria, fungi, and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO). GM plants have been useful in many ways. Genetic modification has

(i) Made crops more tolerant to abiotic stresses (cold, drought, salt, heat).

(ii) Reduced reliance on chemical pesticides (pest-resistant crops).

(iii) Helped to reduce post-harvest losses.

(iv) Increased efficiency of mineral usage by plants (this prevents early exhaustion of fertility of soil).

4. What is a recombinant DNA vaccine? Give two examples.

Ans: A recombinant vaccine is one that is produced using recombinant DNA technology. This includes introducing antigen-coding DNA into bacterial or mammalian cells to trigger an immunological response. Antigenic polypeptides of pathogens may now be produced in bacteria or yeast using recombinant DNA technology. Vaccines made this way enable for large-scale manufacture and hence better availability for vaccination, such as the hepatitis B vaccine (Recombivax HB), which is made from yeast. The single-dose Japanese encephalitis vaccine IMOJEV, which was introduced in 2010 in Australia, was the only human DNA vaccine authorized for human use as of June 2015.

5. Why is it that the line of treatment for a genetic disease is different from infectious diseases?

Ans: An infectious illness develops as a result of the presence of a pathogen. In such cases, the treatment strategy focuses on removing the causal pathogen from the body. A genetic illness, on the other hand, is caused by a genotype abnormality. There is no impact of antibiotics on genetic abnormality. As a result, the treatment for a genetic disease differs significantly from that for an infectious condition.

6. Discuss briefly how a probe is used in molecular diagnostics.

Ans: In a clone of cells, a single-stranded DNA or RNA labeled with a radioactive molecule (probe) is allowed to hybridize to its corresponding DNA, followed by autoradiography detection. Because the probe does not have complementarity with the mutant gene, the clone with the mutated gene will not appear on the photographic film.

7. Who was the first patient who was given gene therapy? Why was the given treatment recurrent in nature?

Ans: In 1990, a 4-year-old child with adenosine deaminase (ADA) deficiency received the first clinical gene therapy. This enzyme is required for the immune system to work properly. The condition is caused by a mutation in the adenosine deaminase gene. ADA deficiency can be remedied in some children by bone marrow transplantation; in others, it can be treated with enzyme replacement therapy, in which the patient receives functioning ADA through injection. However, both of these techniques have the drawback of not being totally curative. Lymphocytes from the patient's blood are cultivated in a culture outside the body as the first step toward gene therapy.

The lymphocytes are then inoculated with a functioning ADA cDNA (through a retroviral vector) before being returned to the patient. The patient, however, requires "periodic injection of such genetically modified lymphocytes" since these cells are not immortal. However, a lasting cure might be achieved if a gene isolate from marrow cells that produce ADA is injected into cells at an early embryonic stage.

8. Taking examples under each category, discuss upstream and downstream processing.

Ans: Upstream processing: Biotechnological processes can be separated into upstream processes and downstream processes. The upstream process is defined as the entire process from DNA isolation and culture expansion of the cells until the final product.

Downstream processing: After the biosynthetic step is completed, the product must go through a number of procedures before it can be marketed as a finished product. Separation and purification are among the procedures, which are referred to as downstream processing. Preservatives must be included in the product's formulation. As with pharmaceuticals, such formulations must go through clinical testing. Each product must also undergo stringent quality control testing. From product to product, downstream processing and quality control tests differ.

9. Define Antigen and Antibody. Name any two diagnostic kits based upon them.

Ans: An antigen is a foreign substance that elicits the formation of an antibody. The antibody is a protein that is synthesized in response to an antigen. Antigen and antibody show a high degree of specificity in binding each other. Two diagnostic kits based on antigen-antibody interaction are:

(a) ELISA for HIV.

(b) Pregnancy test kits.

10. ELISA technique is based on the principles of antigen-antibody interaction. Can this technique be used in the molecular diagnosis of a genetic disorder, such as phenylketonuria?

Ans: Yes. One can use antibodies against the enzyme (that is responsible for the metabolism of phenylalanine) to develop ELISA-based diagnostic techniques. The patient where the enzyme protein is absent would give negative results in ELISA when compared to normal individuals.

11. How is a mature, functional insulin hormone different from its prohormone form?

Ans: Processing pro-hormone, which contains an additional peptide termed C-peptide, yields mature functioning insulin. During the maturation of pro-insulin to insulin, the C-peptide is eliminated.

12. Gene therapy is an attempt to correct a genetic defect by providing a normal gene to the individual. By this, the normal function can be restored. An 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 a reason for your answer.

Ans: Enzyme replacement treatment involves injecting the needed enzyme into the patient's body artificially. This aids in the disease's care. However, in order to keep the therapy going, the enzyme and other required medications must be re-administered on a regular basis. The majority of the time, counseling is expensive and causes financial and emotional strain on the patient. Gene correction is a long-term solution. For example, if the necessary gene is delivered at the embryonic stage, a person with ADA deficiency can be permanently healed. Pedigree analysis can be used to determine the disease's likelihood of occurrence. The patient's quality of life will improve as a result of this.

13. Transgenic animals are the animals in which a foreign gene is expressed. Such animals can be used to study the fundamental biological process, a phenomenon as well as for producing products useful for mankind. Give one example for each type.

Ans: The following are some examples of transgenic animal applications:

(a) Basic Biological Processes: Transgenic mice can be utilized to learn more about human insulin-like growth factors.

(b) Disease Research: Many transgenic animals are implanted with disease-causing genes. These animals can then be used to study illness progression and possible cures.

(c) Biological Products: A transgenic cow named Rosie could produce protein-fortified milk with 2.4 grams of lactalbumin per liter.

14. When a foreign DNA is introduced into an organism, how is it maintained in the host and how is it transferred to the progeny of the organism?

Ans: In most cases, a foreign gene is ligated to a plasmid vector and then injected into the host. The foreign gene is reproduced and its copies are created as the plasmid multiplies and creates many copies of itself. When the host organism splits, the plasmid DNA containing the foreign gene is passed down to the offspring.

15. Bt cotton is resistant to pests, such as lepidopteron, dipterans, and coleopterAns: Is Bt cotton also resistant to other pests as well?

Ans: Cotton that has been genetically modified to withstand only a few pest taxa is known as Bt cotton. Other pests are quite likely to infest these Bt cotton plants in the future. It has a comparable immunization against smallpox, but it does not protect against other organisms that cause cholera, typhoid, and other diseases.

Long Answer Type Questions

1. A patient is suffering from ADA deficiency. Can he be cured? How?

Ans: In 1990, a 4-year-old child with adenosine deaminase (ADA) deficiency received the first clinical gene therapy. This enzyme is required for the immune system to work properly. The condition is caused by a mutation in the adenosine deaminase gene. In some children, ADA deficiency can be treated with bone marrow transplantation; in others, it can be treated with enzyme replacement therapy, which involves injecting the patient with functioning ADA. However, both of these techniques have the drawback of not being totally curative. Lymphocytes from the patient's blood are cultivated in a culture outside the body as the first step toward gene therapy.

The lymphocytes are then inoculated with a functioning ADA cDNA (through a retroviral vector) before being returned to the patient. However, because these cells are not immortal, the patient will need to get infusions of genetically altered lymphocytes on a regular basis. However, a lasting cure might be achieved if a gene isolated from marrow cells that produce ADA is injected into cells at an early embryonic stage.

2. Define transgenic animals. Explain in detail any four areas where they can be utilized.

Ans: Transgenic animals are the products of genetic engineering and express specific gene(s) from totally unrelated sources. Following are the four main areas where they can be utilized: 

(1) These animals may be used to research normal physiology and development, as well as which factors/gene products are required at different stages of development. They aid scientists in understanding normal gene expression at various phases of growth and development by expressing certain genes.

(2) Study of Diseases: Transgenic animals can be created to serve as models for various human diseases. They also help us understand the involvement of various genes in diseases like cancer, Parkinson’s disease, etc.

(3) Vaccine safety: Vaccines such as the polio vaccine can be tested using transgenic animals. In the future, vaccination testing on monkeys will be replaced by transgenic mice, which have demonstrated promising results in this field.

(4) Chemical safety testing: Transgenic animals that are more sensitive to particular chemicals/drugs are developed. These are used to investigate a chemical or drug's toxicity or adverse effects. The benefit is that we obtain outcomes more quickly.

3. You have identified a useful gene in bacteria. Make a flow chart of the steps that you would follow to transfer this gene to a plant.

Ans: After identifying a useful gene in bacteria, the following steps should be undertaken:

4. Highlight five areas where biotechnology has influenced our lives.

Ans: The applications of biotechnology include:

1. therapeutics and diagnostics

2. genetically modified crops for agriculture

3. processed food

4. bioremediation

5. waste treatment and energy production.

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

Ans: GM plants have been useful in many ways. Genetic modification has:

1. Made crops more tolerant to abiotic stresses (cold, drought, salt, heat). 

2. Reduced reliance on chemical pesticides (pest-resistant crops).

3. Helped to reduce post-harvest losses.

4. Increased efficiency of mineral usage by plants (this prevents early exhaustion of fertility of soil).

5. Enhanced nutritional value of food-e.g., Vitamin ‘A’ enriched rice.

6. Explain with the help of one example how genetically modified plants can:

(a) Reduce Usage of Chemical Pesticides.

Ans: Reduce the use of chemical pesticides: Bt toxin is generated by the Bacillus thuringiensis bacteria (Bt). The Bt toxin gene was cloned from bacteria and produced in plants to give insect resistance without the use of pesticides, resulting in a bio-pesticide. Bt cotton, Bt com, rice, tomato, potato, and soybean are just a few examples.

(b) Enhance the Nutritional Value of Food Crops

Ans: Enhance the nutritional value of food crops: Golden rice is the transgenic variety of basmati rice which gives a high yield and is rich in vitamin A, so it is used in the deficiency of vitamin-A causing night blindness and skin disorder.

7. List the disadvantages of insulin obtained from the pancreas of slaughtered cows and pigs.

Ans: The disadvantages of insulin obtained from the pancreas of slaughtered cows and pigs are-

1. Insulin is a hormone that is only generated in trace levels in the body.

2. As a result, a significant number of animals must be slaughtered in order to get modest amounts of insulin. As a result, the price of insulin is quite expensive. (Demand is several times more than supply).

3. Animal slaughtering is also unethical.

4. Humans may develop an immunological response to insulin generated from animals when it is given to them.

5. There's a chance that slaughtered animals are infected with an infectious microbe that might taint insulin.

8. List the advantages of recombinant insulin.

Ans: Recombinant insulin has the following advantages: 

(i) There are no animals slaughtered in the manufacture of recombinant insulin.

(ii) Patients were not allergic to recombinant insulin, but animal-derived insulin caused some patients to develop allergies or other sorts of responses to the foreign protein.

(iii) Recombinant insulin is not particularly expensive.

9. What is meant by the term bio-pesticide? Name and explain the mode of action of a popular bio-pesticide.

Ans: Biopesticide is a pesticide that is

(a) not chemical in nature

(b) more specific in action against the pest

(c) safer for the environment than chemical pesticides

Bt toxin, generated by a bacteria called Bacillus thuringiensis, is a well-known bio-pesticide. This bacterium's Bt-toxin gene has been cloned and expressed in plants. When swallowed by the insect, the Bt toxin protein is transformed to its active form due to the alkaline pH of the stomach. The active toxin attaches to the surface of midgut epithelial cells, causing cell swelling and lysis, and ultimately killing the insect.

10. Name the five key tools for accomplishing the tasks of recombinant DNA technology. Also, mention the functions of each tool.

Ans: The five key tools for accomplishing the tasks of recombinant DNA technology are -

1. Restriction endonucleases: for cutting the desired DNA at desired places

2. Gel electrophoresis: for separating the desired DNA fragments

3. Ligase enzyme: for creating recombinant DNA molecules.

4. DNA delivery system: like electroporation, microinjection, gene gun method.

5. Competent host (usually bacteria/yeast): to take up recombinant DNA.

Use of Exemplar Problems Class 12 Biology

These NCERT Exemplar Problems for Class 12 Biology are not intended to be used solely as a question bank for exams, but rather to increase the level of knowledge or learning in schools. These NCERT Exemplar Problems for Class 12 Biology are meant to motivate instructors and students to create high-quality discussion topics. These example books feature high-quality questions based on the most recent CBSE Syllabus for thorough chapter practice. Every year, exemplary questions are incorporated in CBSE Board Papers to improve the examination quality.

The NCERT Biology Exemplar Solution Chapter 12 Biotechnology and its applications major purpose is to provide instructors and students with a large number of high-quality problems of varied cognitive levels to aid in the teaching-learning of ideas in all NCERT Solutions for Classes 6 to 12. The questions in these volumes are meant to aid teachers in creating balanced question papers for unit and terminal examinations, as well as preparing assignments, evaluating their teaching effectiveness, and learning about their student’s successes.

Teachers may benefit from feedback based on the analysis of students' replies to help them improve the quality of their classroom instruction. Furthermore, the Biology questions are difficult to answer. Exemplar Solutions Chapter 12 Biotechnology and its applications are required to aid instructors in comprehending the essential components of high-quality questions and to encourage them to write their own. Students can help themselves by completing the self-assessment problems in the Exemplar book and understanding the basic problem-solving techniques. Some of the book's questions are intended to assess students' grasp of concepts and their ability to apply them in new settings.