NCERT Exemplar Class 12 Biology Solutions Chapter 12 Biotechnology and Its Applications

Question:2

Expand GMO. How is it different from a hybrid

Answer:

GMO stands for Genetically Modified Organism. A hybrid is produced after crossing two different kinds of individuals, while a GMO is produced by alteration in the gene, which is carried out in vitro.

Question:4

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

Answer:

ELISA stands for Enzyme-Linked Immunosorbent Assay. AIDS can be detected using this procedure. Antigen-antibody reaction is the underlying principle in this test.

Question:5

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

Answer:

Detection of a disease before the appearance of symptoms is now possible by using biotechnology. PCR (Polymerase Chain Reaction) helps in doing this. Use of PCR can amplify the nucleic acids of bacteria or virus. This can help in detecting their presence even when they are in low concentration.

Question:6

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

Answer:

Biopiracy is the use of bio-resources by MNCs and other organisations without authorisation from the countries and people. Some MNCs make some minor tweaks to get the patent on products or processes which have been under the domain of traditional knowledge of any country. By obtaining the patent, these companies get a license to exploit the worldwide market. This leaves the people (with traditional knowledge) at the losing end. Patent on turmeric by an American company is a good example of biopiracy. Turmeric has been used as an antiseptic in India for ages and hence is part of the traditional knowledge.

Question:7

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

Answer:

When the toxin is present in an inactive form, it does not harm the organism, which produces the toxin. For example; B. thuringiensis produces an insecticidal toxin which does not kill this bacterium. This toxin becomes active when it enters alkaline pH of the gut of an insect and the insects killed in the process.

Question:8

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

Answer:

When a genetically modified organism is introduced into the ecosystem, it can have dire consequences for the ecosystem. Thus, not respecting the genetic barriers (while creating genetically modified organisms) can have long-term repercussions on the ecosystem.

Question:9

Why has the Indian Parliament cleared the second amendment of the country's patents bill?

Answer:

It was observed that some MNCs or other organizations obtained a patent on products or services which had been part of the traditional knowledge of developing countries. This act had the potential of exploitation of indigenous people by not providing adequate compensation and by commercial exploitation.
To prevent such misuse of patents, the Indian Parliament cleared the second amendment of the country’s patent bill.

Question:10

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

Answer:

The following are the two reasons why the patent on Basmati should not have gone to an American Company:

1. A total of 27 documented varieties of Basmati is being grown in India, and thus it is an integral part of traditional farm practices in India.
2. The patent could have prevented Indian people from growing Basmati rice.

Question:11

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

Answer:

Before the advent of rDNA technology, Insulin was mainly obtained from the pancreas of slaughtered animals. This often resulted in unwanted side effects on the users.

Question:12

Concerning understanding diseases, discuss the importance of transgenic animal models.

Answer:

Transgenic animals can serve as models to understand the progression of various disease in human. Transgenic models exist for many human diseases like cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s. These animals can be observed to understand the causative gene for a particular disease. This can help in devising suitable treatment for some particular diseases.

Question:13

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

Answer:

Rosie was the first transgenic cow, and it was produced in 1997. The gene for human protein alpha-lactalbumin was introduced in this cow. Thus, the cow could produce protein-enriched milk. This milk was nutritionally more balanced than natural cow milk.

Question:14

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

Answer:

Use of PCR can amplify the nucleic acids of bacteria or virus. This can help in detecting their presence even when they are in low concentration. This helps in early detection of a disease which was not possible with conventional diagnostic tools. By the time, conventional diagnostic tools could detect a disease; it was very late because of the very high concentration of pathogens. Nevertheless, early detection by using PCR can help in timely and more efficient treatment.

Question:15

What is GEAC, and what are its objectives?

Answer:

The full form of GEAC is Genetic Engineering Approval Committee. The Government of India has formed this committee. The following are its main objectives:

1. The validity of GM research.
2. Assessing the safety of the introduction of GM products among the public.

Question:16

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

Answer:

The patent was filed for Basmati rice.

Question:17

Discuss the advantages of GMOs.

Answer:

The following are the advantages of GMOs:

1. GM crops are more tolerant of various stresses.
2. GM crops reduce the reliance on pesticides and synthetic fertilizers.
3. GM crops can enhance the nutrient value of a particular food.

Question:2

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

Answer:

Traditional knowledge accumulates over thousands of generations. It carries the knowledge of cost-effective ways to tackle many problems related to human life. A patent is granted to a new product or service, which is based on an entirely novel or new concept. Once an organization or an individual obtains a patent for a particular product or service, it gets the sole right to reap commercial benefits from that product or service.
In most of the cases, the patent holder tends to overexploit the market during the patent period. If we used traditional knowledge instead, it would help us in saving a lot of money. This shows that ignoring our traditional knowledge can prove costly in the area of biological patenting.

Question:3

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

Answer:

Genetic modification of plants has been useful in the following areas:

1. Increased tolerance to abiotic stress (drought, salinity, high temperature, etc.)
2. Increased tolerance to biotic stress, like pests and weeds.
3. Increased efficiency of mineral usage from the soil.
4. Enhanced nutritional value.

Question:4

What is a recombinant DNA vaccine? Give two examples.

Answer:

A vaccine, which is prepared by using recombinant DNA technology, is called an rDNA vaccine. Enzo Paolette and Dennis Panicali from New York State Department of Health were able to transform smallpox vaccine so that it could be effective against some other diseases.
Thus, they were the pioneers in making an rDNA vaccine. Hepatitis B vaccine and the HPV vaccine are two examples of rDNA vaccines.

Question:5

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

Answer:

An infectious disease happens because of some pathogen. The line of treatment in such condition is focused on eliminating the causative pathogen from the body. However, a genetic disease happens because of some anomaly in the genotype.
No antibiotic has an effect on genotype anomaly. Hence, the line of treatment for a genetic disease is entirely different from infectious disease.

Question:6

Discuss briefly how a probe is used in molecular diagnostics.

Answer:

For molecular diagnostics: a single strand DNA or RNA is tagged with a radioactive probe. It is then introduced into the host cell and allowed to hybridize with its complementary DNA in a clone of cells which are formed in vitro. The cloned cells are then observed using radiography. This helps in detecting the problems.

Question:7

Who was the first patient to receive gene therapy? Why was the given treatment recurrent in nature?

Answer:

A four-year-old girl was the first patient to be given gene therapy. She was suffering from adenosine deaminase (ADA) deficiency, and this therapy was given in 1990. The treatment with gene therapy involves manipulating the DNA of lymphocytes from the patient’s body.
The modified lymphocytes are grown in vitro and then infused into the patient’s body. We know that lymphocytes are not immortal, but they have a definite life span. Due to this, this treatment is recurrent in nature.

Question:8

Taking examples under each category, discuss upstream and downstream processing

Answer:

Upstream processing: This involves identifying a material, which can be transformed for making the final product. Let us take the example of making BT cotton. In this, extracting the gene for insecticide toxin from B. thuringiensis is an example of upstream processing. Similarly, introducing this gene into cotton is an upstream process.

Downstream processing: This involves suitable purification and isolation of the final product. Let us take that example of fermentation to understand this. Purification of alcohol through distillation is part of downstream processing.

Question:9

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

Answer:

Antigen: A foreign substance, which elicits an immune response from the body, is called an antigen.
Antibody: A protein, which is synthesized in response to an antigen in the body, is called an antibody.
Two diagnostic kits, based on antigen and antibody, are as follows:
(a) ELISA kit
(b) Pregnancy test kit

Question: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?

Answer:

Yes. One can use an antibody against the enzyme (that is responsible for the metabolism of phenylalanine) to develop ELISA based is a diagnostic technique. The patient in which the enzyme protein is absent would give a negative result in ELISA when compared to a normal individual.

Question:11

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

Answer:

Insulin in its prohormone form is not active and it needs to be mature to become the functional Insulin. The prohormone form of Insulin contains an extra stretch of a polypeptide called C peptide. When Insulin becomes mature, it is devoid of C peptide.

Question: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 do you opinion is a better option? Give a reason for your answer.

Answer:

Enzyme replacement therapy works by artificially administering the required enzyme into the patient’s body. This helps in the management of the disease. However, this needs frequent re-administration of the enzyme and other necessary drugs to continue the therapy. In most cases, the therapy is costly and is a cause of financial and emotional drain on the patient. Using gene correction is a permanent solution. For example, a person with an ADA deficiency can be permanently cured if the required gene is introduced during the embryo stage. This will ensure a better quality of life for the patient.

Question:13

Transgenic animals are 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.

Answer:

The following are examples of various uses of transgenic animals:
(a) Fundamental biological processes: Transgenic animals can be used to understand insulin-like growth factors in humans:
(b) Study of Diseases: Many transgenic animals are introduced with genes for a certain disease. Then the progression and possible cure for such a disease can be studied using these animals.
(c) Biological Products: A transgenic cow, Rosie, could produce protein-enriched milk

Question: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?

Answer:

When a foreign DNA is introduced into an organism, it binds with the chromosome of the host organism because of recombination. When progeny of the host organism is produced (through sexual or asexual reproduction), the new gene is passed on to the progeny because of inheritance. This is similar to any defective gene being passed on from one generation to the next.

Question:15

Bt cotton is resistant to pests, such as lepidopterans, dipterans and coleopterans. Is BT cotton also resistant to other pests?

Answer:

The genes from Bacillus thuringiensis are pest-specific. This means that they are highly effective against a select group of pests but do not harm other insects. As a corollary, Bt cotton is not resistant to other pests. This is, in fact, an advantage from the perspective of maintaining biodiversity in the environment. Beneficial insects are saved from harm because farming of Bt cotton does not need the use of pesticides.

Question:2

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

Answer:

Transgenic animals are animals in which a foreign gene is expressed. Transgenic rats, pigs, cows, rabbits, sheep, and fish have been produced. However, more than 95% of all transgenic animals are mice. Four areas in which transgenic animals can be utilized are as follows:
(a) Fundamental Biological Processes: Transgenic animals can be used to understand insulin-like growth factors in humans: A particular factor can be introduced from another animal, and then the behaviour of this factor can be studied in the transgenic animal.
(b) Study of Diseases: Many transgenic animals are introduced with genes for a certain disease. The progression and possible cure for such a disease can be studied using these animals. Today,
Models of transgenic animals exist in which cancer, cystic fibrosis, rheumatoid arthritis, etc., can be studied.
(c) Biological Products: A transgenic cow, Rosie, could produce human protein-enriched milk. This milk contains 2.4 g of human alpha-lactalbumin per litre. This milk is nutritionally balanced for babies than normal cow milk.
(d) Vaccine Safety: Before approval for use in humans, any vaccine needs to prove its safety on model animals. For example, transgenic mice have been used to study the safety of polio vaccine.

Question: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.

Answer:

The following are the steps for transferring the useful gene to a plant.
(a) Isolation of useful gene using Restriction Endonucleases
(b) Transferring the gene to a suitable vector to create a recombinant DNA molecule
(c) Transfer of these recombinant DNA molecules to the target cells
(d) Screening of cells for transformation
(e) Selection of transformed cells
(f) Regeneration of plants from the transformed cells to get transgenic plants.

Question:4

Highlight five areas where biotechnology has influenced our lives.

Answer:

(a) Food Security: The earlier Green Revolution has certain limitations. Biotechnology can help in overcoming those limitations. It can help in improving food production to meet the growing demand because of a growing population. Production of Spirulina is an example, which shows that a huge quantity of nutrient can be produced by minimum use of land.
(b) Medicine: Many vaccines and other pharmaceuticals products have been made through biotechnology. Several diagnostic techniques; using biotechnology; has made it easier to diagnose a disease in time and has helped in better cure.
(c) Environmental Protection: Use of Bt cotton helps in minimizing the use of pesticides. This is beneficial for the environment because it helps in saving useful insects.
(d) Crime Detection: DNA fingerprinting can be used to trace the identity of a criminal by using even the smallest remains of a criminal’s body parts.
(e) Legal Disputes: Parentage disputes are being settled with the use of DNA fingerprinting.

Question:5

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

Answer:

Advantages of using GM plants are as follows:

1. GM crops are more tolerant to abiotic stresses, like drought, salinity, high temperature, etc. Thus, GM modified crops can also be grown in areas which are not ideal for cultivation.
2. GM crops reduce the need for chemical pesticides. This helps in saving many useful insects which otherwise get killed by chemical pesticides. It is important to remember that many insects facilitate pollination in crops.
3. Mineral usage by a plant is more efficient in case of GM crops. This prevents early exhaustion of soil nutrients.
4. GM crops can have enhanced nutritional value. For example, golden rice is fortified with vitamin A. Similarly, the carrot has been fortified with iron.

GM crops can be tailor-made to provide alternative resources to industries, such as starch or fuel.

Question:6

Explain with the help of one example of how genetically modified plants can:
(a) Reduce the usage of chemical pesticides
(b) Enhance the nutritional value of food crops

Answer:

(a) Bt cotton contains a gene, which has a pesticidal role. This gene is pest-specific and affects only certain pests. By encountering most of the common pests of cotton, Bt cotton minimizes the use of chemical pesticides.
(b) Biofortification involves the addition of nutrients through genetic engineering. This can also be achieved through conventional breeding methods. Biofortification is beneficial because a plant product has inbuilt extra nutrients in it. This means that nutrients need not be added at the processing stage. This can help in tackling hidden hunger among the poor. Golden rice is an example of rice which has been fortified with vitamin A.

Question:7

List the disadvantages of Insulin obtained from the pancreas of slaughtered cows and pigs:

Answer:

The following are the disadvantages of Insulin from slaughtered animals:
(a) Demand for Insulin is very high, which necessitates slaughtering a large number of animals.
(b) Slaughtering of animals amounts to cruelty against animals.
(c) Insulin from animal origin can result in allergic reactions because the body tends to encounter a foreign substance.
(d) The slaughtered animal can be infected with some dangerous microbes. This can contaminate the Insulin.

Question:8

List the advantages of recombinant Insulin.

Answer:

The following are the advantages of recombinant Insulin:
(a) Recombinant Insulin can be prepared on a large scale without worrying about the source animal.
(b) Batch-to-batch consistency can be maintained, and quality can be maintained.
(c) Helps in preventing cruelty against animals.
(d) Chances of allergic reactions have been minimized.
(e) Chances of transmission of infection from source animals have been nullified.
(f) Recombinant Insulin has almost replaced animal-sourced Insulin from around the world.
(g) This paves the way for forms of Insulin, which need not be given through injections.

Question:9

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

Answer:

A biological agent, which works as a pesticide, is called a biopesticide. Biopesticides can be of the following types:
(a) Microbial: Many Bacteria and fungi have pesticidal properties.
(b) Herbal: Some plants, like neem and canola, can help in controlling pesticides.
(c) Plant Incorporated Protectants: These are incorporated into the genes of a plant through genetic engineering. Bt cotton is an example of a plant with the incorporated pesticidal property.
Bacillus thuringiensis affects the pests of Lepidoptera, Coleoptera and Diptera. It is a well-known example of a microbial pesticide. A gene in B. thuringiensis produces a toxin, which remains inactive in the bacterium. Once this toxin enters the gut of the pest, the Alkaline pH makes it active. The toxin results in perforations in the gut of the pest, and eventually, the pest is killed. This gene has been incorporated into Bt cotton, Bt tomato, Bt brinjal, etc. These GM crops are giving good results.

Question:10

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

Answer:

Key tools in rDNA technology
(a) Restriction endonuclease.
(b) Gel electrophoresis
(c) Ligase enzyme
(d) DNA delivery system

Functions

1. Cutting the desired DNA at the desired locations
2. Separating the desired DNA fragments.
3. Creating a recombinant DNA molecule
4. To introduce a gene in the host

Question:2

C-peptide of human Insulin is:
a. A part of a mature insulin molecule
b. Responsible for the formation of disulphide bridges
c. Removed during maturation of pro-insulin to insulin
d. Responsible for its biological activity

Answer: The correct answer is option (c) Removed during maturation of pro-insulin to insulin
Explanation: The C-peptide joins A and B chains in pro-insulin. During insulin formation, it is removed, and only A and B chains remain as active insulin.

Question:3

GEAC stands for:
a. Genome Engineering Action Committee
b. Ground Environment Action Committee
c. Genetic Engineering Approval Committee
d. Genetic and Environmental Approval Committee

Answer: The correct answer is option (c) Genetic Engineering Approval Committee
Explanation: GEAC is the Indian committee that approves the use of genetically modified organisms for research and commercial use.

Question:4

α-1 antitrypsin is:

a. An antacid
b. An enzyme
c. Used to treat arthritis
d. Used to treat emphysema

Answer: The correct answer is option (d) Used to treat emphysema
Explanation: α-1 antitrypsin is a protein that protects the lungs and its deficiency can lead to emphysema, and it is given as a treatment.

Question:5

A probe, which is a molecule used to locate homologous sequences in a mixture of DNA or RNA molecules could be:
a. An ssRNA
b. An ssDNA
c. Either RNA or DNA
d. Can be ssDNA but not ssRNA

Answer: The correct answer is option (c) Either RNA or DNA
Explanation: A probe can be single-stranded RNA or DNA and binds to its complementary sequence to help detect specific genes.

Question:6

Choose the correct option regarding Retrovirus:
a. An RNA virus that synthesizes DNA during infection
b. A DNA virus that synthesizes RNA during infection
c. An ssDNA virus
d. A dsRNA virus

Answer: The correct answer is option (a) An RNA virus that synthesizes DNA during infection
Explanation: Retroviruses use reverse transcriptase to make DNA from their RNA, which then gets integrated into the host genome.

Question:7

The site of production of ADA in the body is:
a. Erythrocytes
b. Lymphocytes
c. Blood plasma
d. Osteocytes

Answer: The correct answer is option (b) Lymphocytes
Explanation: ADA (Adenosine Deaminase) is mainly produced in lymphocytes, which play a key role in immune function.

Question:8

A protoxin is:
a. A primitive toxin
b. A denatured toxin
c. The toxin produced by protozoa
d. Inactive toxin

Answer: The correct answer is option (d) Inactive toxin
Explanation: A protoxin is inactive when produced and gets activated inside the insect's gut due to alkaline pH, as seen in Bacillus thuringiensis.

Question:9

Pathophysiology is the:
a. Study of the physiology of the pathogen
b. Study of the normal physiology of the host
c. Study of altered physiology of the host
d. None of the above

Answer: The correct answer is option (c) Study of altered physiology of the host
Explanation: Pathophysiology is a combination of pathology and physiology. While physiology is about various biological processes, pathology is about a diseased state.

Question: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 gut
d. Mechanical action in the insect gut

Answer: The correct answer is option (c), Alkaline pH of the gut
Explanation: The Alkaline pH of the gut of insects converts inactive protoxin into active toxin. This kills the insect.

Question:11

Golden rice is:
a. A variety of rice grown along the Yellow River in China
b. Long stored rice has a yellow colour tint
c. A transgenic rice having the gene for β-carotene
d. The wild variety of rice with yellow coloured grains

Answer: The correct answer is option (c), A transgenic rice having the gene for beta-carotene
Explanation: A transgenic rice having the gene for beta-carotene is called golden rice due to its color.

Question:12

In RNAi, genes are silenced using:
a. ss DNA
b. ds DNA
c. ds RNA
d. ss RNA

Answer: The correct answer is option (c) ds RNA
Explanation: In RNA interference (RNAi), double-stranded RNA is used to silence specific gene expression.

Question:13

The first clinical gene therapy was done for the treatment of:

a. AIDS
b. Cancer
c. Cystic fibrosis
d. SCID (Severe Combined Immune Deficiency resulting from deficiency of ADA)

Answer: The correct answer is option (d) SCID (Severe Combined Immune Deficiency resulting from deficiency of ADA)
Explanation: The first clinical gene therapy was given in 1990 to a 4-year-old girl with adenosine deaminase (ADA) deficiency.

Question:14

ADA is an enzyme which is deficient in a genetic disorder, SCID. What is the full form of ADA?
a. Adenosine deoxyaminase
b. Adenosine deaminase
c. Aspartate deaminase
d. Arginine deaminase

Answer: The correct answer is option (b) Adenosine deaminase
Explanation: ADA stands for Adenosine Deaminase, which is essential for the immune system’s proper function.

Question:15

Silencing of a gene could be achieved through the use of:
a. RNAi only
b. antisense RNA only
c. both RNAi and antisense RNA
d. none of the above

Answer: The correct answer is option (c) both RNAi and antisense RNA
Explanation: Both RNA interference (RNAi) and antisense RNA can block gene expression by preventing mRNA from making proteins.