CBSE Class 12 Biology Biotechnology and its Applications Assignment Set A

Answer: c

Question: Biopatent means
a) right to use an invention
b) right to use biological resources
c) right to use applications are processes
d) All of the above

Answer: d

Question: Applications like bioremediation, processed food, therapeutics and diagnostics are related to
a) biochemistry
b) microbiology
c) biotechnology
d) medical science

Answer: c

Question: Technique used to detect mutated genes is called
a) gel electrophoresis
b) polymerase chain reaction
c) gene therapy
d) autoradiography

Answer: d

Question: Plants, bacteria, fungi and animals whose genes have been altered by manipulation are called
a) genetically modified organisms
b) hybrid organisms
c) pest resistant organisms
d) insect resistant organisms

Answer: a

Question: Which bacterium was the first to be used as biopesticide on the commercial scale in the world?
a) Bacillus thuringiensis
b) Escherichia coli
c) Pseudomonas aeruginosa
d) Agrobacterium tumefaciens

Answer: a

Question: Bt toxin protein crystals present in bacterium Bacillus thuringiensis, do not kill the bacteria because
a) bacteria are resistant to the toxin
b) bacteria enclose toxins in a special sac
c) toxins occur as inactive protoxins in bacteria
d) None of the above 

Answer: c

Question: Organic agriculture is a technique of raising crops for
a) increased food production
b) reduction in required labour
c) increasing the use of agrochemicals
d) None of the above

Answer: d

Question: Which of the following nematodes infects the root of the tobacco plants which reduces the production of tobacco?
a) Wuchereria
b) Ascaris
c) Meloidegyne incognita
d) Enterobius

Answer: c

Question: GM crops are designed to develop natural resistance from insects and pests. Which of the following crops are modified using Bacillus thuringiensis?
a) Corn and cotton
b) Tomato and rice
c) Patato and soybean
d) All of the above

Answer: d

Question: RNAi stands for
a) RNA interference
b) RNA interferon
c) RNA inactivation
d) RNA initiation

Answer: a

Question: What is the term used for animals that made to carry genes, which make them more sensitive to the toxic substances
than other normal animals?
a) Transgenic
b) Transversion
c) Transition
d) Transformant

Answer: a

Question: What is the demerit of using bovine insulin (from cow) and porcine insulin (from pig) in diabetic patients?
a) It leads to hypercalcemia
b) It is expensive
c) It may cause allergic reactions
d) It may lead to mutations in human genome

Answer: c

Question: Which step was proved to be the main challenge in the production of human insulin by recombinant DNA technology?
a) Splitting A and B–peptide chain
b) Addition of C-peptide to proinsulin
c) Getting insulin assembled into mature form
d) Removal of C-peptide from active insulin

Answer: c

Question: Bt toxin is
a) intracellular crystalline protein
b) extracellular crystalline protein
c) intracellular monosaccharide
d) extracellular polysaccharide

Answer: a

Question: Second generation vaccines are prepared by recombinant DNA technology. Which of the following is/are examples of
such vaccines?
a) Herpes virus vaccine
b) Hepatitis-B virus vaccine
c) Solk’s polio vaccine
d) Both (a) and (b)

Answer: d

Question: Which polypeptide chain is removed during the maturation of proinsulin into insulin?
a) A-chain ( 21 amino acids)
b) B-chain ( 30 amino acids)
c) C-chain ( 33 amino acids)
d) A and B-chains

Answer: c

Question: A patient has a defective gene for the enzyme Adenosine Deaminase (ADA). He/She lacks functional cells and therefore, fails to fight the infecting pathogens. The cells are
a) B-lymphocytes
b) Phagocytes
c) T-lymphocytes
d) Both (a) and (c)

Answer: d

Question: Adenosine Deaminase (ADA) deficiency can be cured by …A… and …B… but it is not fully curative. Here, A and B
can be
a) A–gene therapy, B–radiation therapy
b) A–bone marrow transplantation, B–enzyme replacement therapy
c) A–organ transplantation, B–hormone replacement therapy
d) A–radiation therapy, B–enzyme replacement therapy

Answer: b

Question: Which one of the following molecular diagnostic techniques is used to detect the presence of a pathogen in its early stage of infection?
a) Angiography
b) Radiography
c) Enzyme replacement technique
d) Polymerase Chain Reaction (PCR)

Answer: d

Question: Biopiracy is related to which of the following?
a) Traditional knowledge exploitation
b) Biomolecules and regarding bioresources exploitation
c) Stealing of bioresources
d) All of the above

Answer: d

Question: In which of the following methods, a probe is allowed to hybridise to its complementary DNA in the clone of cells?
a) Gene therapy
b) Autoradiography
c) Polymerase chain reaction
d) Enzyme-Linked Immuno Sorbent Assay (ELISA)

Answer: b

Question: Animals whose DNA is manipulated to possess and express an extra (foreign) gene are known as
a) transgenic animals
b) hybrid animals
c) transversion animals
d) All of the above

Answer: a

Question: Transgenic animals are those which have foreign
a) DNA in all of their cells
b) Proteins in all of their cells
c) RNA in all of their cells
d) RNA in some of their cells

Answer: a

Question: For the first time, gene therapy was tried on a 4 year old girl in 1990 to treat which of the following enzyme deficiency?
a) Cytosine Deaminase (CDA)
b) Adenosine Deaminase (ADA)
c) Tyrosine oxidase
d) Glutamate trihydrogenase

Answer: b

Question: Transgenic animals that serve as model to study many human diseases such as …… .
a) Alzheimer’s disease
b) cancer
c) night blindness
d) Both (a) and (b)

Answer: d

Question: A monopoly granted to a person who has either invented a new and useful article, made improvement in an existing
article or invented a new process of making an article is called
a) bioethics
b) patent
c) biopiracy
d) genetic recombination

Answer: b

Question: Basmati is unique for its aroma and flavour, whose A… documented varieties are cultivated in B… .Here, A and B refer to
a) A–27, B–America
b) A–30, B–America
c) A–27, B–India
d) A–30, B–India

Answer: c

Question: The bacterium, Bacillus thuringiensis is widely used in contemporary biology as an alternative of
a) insecticides
b) agent for the production of dairy products
c) source of industrial enzyme
d) indicator of water pollution

Answer: a

Question: Which of the following option is related to bioethics?
a) Process of discovery and commercialisation of new products
b) Use of bioresources without proper authorisation
c) Both (a) and (b)
d) Standards used to regulate human activities in relation to the biological world

Answer: d

Question: Which of the following transgenic animals are used in testing safety of polio vaccine before they are used on
human?
a) Transgenic cow
b) Transgenic monkey
c) Transgenic mice
d) Transgenic sheep

Answer: c

Question: Which step has been taken by Indian Parliament to meet and fulfil the requirements of patent terms and other emergency provisions in this regard?
a) Biopiracy act
b) Indian Patents Bill
c) Biowar act
d) Bioethics act

Answer: b

Question. Which one of the following is a correct statement?
(a) "Bt" in "Bt-cotton" indicates that it is a 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 enhanced the production of ethylene which improves its taste.
Answer : C

Question. Cultivation of Bt cotton has been much in the news. The prefix Bt means 
(a) barium-treated cotton seeds
(b) bigger thread variety of cotton with better tensile strength
(c) produced by biotechnology using restriction enzymes and ligases
(d) carrying an endotoxin gene from Bacillus thuringiensis
Answer : D

Question. Golden rice is a transgenic crop of the future with the following improved trait 
(a) High lysine (essential amino acid) content
(b) Insect resistance
(c) High protein content
(d) High vitamin-A content
Answer : D

Question. Read the following four statements (1-4) about certain mistakes in two of them
1. The first transgenic buffalo, Rosie produced milk which was human alphalactal albumin enriched.
2. Restriction enzymes are used in isolation of DNA from other macro-molecules.
3. Downstream processing is one of the steps of R-DNA technology.
4. Disarmed pathogen vectors are also used in transfer of R-DNA into the host.
Which are the two statements having mistakes?
(a) Statement 2 and 3
(b) Statement 3 and 4
(c) Statement 1 and 3
(d) Statement 1 and 2
Answer : D

Question. A transgenic food crop which may help in solving the problem of night blindness in developing countries is 
(a) golden rice
(b) Bt soyabean
(c) flavr - savr tomato
(d) starlink maize
Answer : A

Ques. What is true about Bt toxin?
(a) Bt protein exists as active toxin in the Bacillus.
(b) The activated toxin enters the ovaries of the pest to sterilise 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. 

Answer: D

Ques. Transgenic plants are the ones
(a) generated by introducing foreign DNA into a cell and regenerating a plant from that cell
(b) produced after protoplast fusion in artificial medium
(c) grown in artificial medium after hybridization in the field
(d) produced by a somatic embryo in artificial medium. 

Answer: A

Ques. The bacterium Bacillus thuringiensis is widely used in contemporary biology as
(a) insecticide
(b) agent for production of dairy products
(c) source of industrial enzyme
(d) indicator of water pollution. 

Answer: A

Ques. What is antisense technology?
(a) When a piece of RNA that is complementary in sequence is used to stop expression of a specific gene
(b) RNA polymerase producing DNA
(c) A cell displaying a foreign antigen used for synthesis of antigens
(d) Production of somaclonal variants in tissue cultures 

Answer: A

Ques. Cry I endotoxins obtained from Bacillus thuringiensis are effective against
(a) nematodes
(b) bollworms
(c) mosquitoes
(d) flies. 

Answer: B

Ques. A transgenic food crop which may help in solving the problem of night blindness in developing countries is
(a) Bt soybean
(b) Golden rice
(c) Flavr Savr tomatoes
(d) Starlink maize. 

Answer: B

Ques. Main objective of production/use of herbicide resistant GM crops is to
(a) encourage eco-friendly herbicides
(b) reduce herbicide accumulation in food articles for health safety
(c) eliminate weeds from the field without the use of manual labour
(d) eliminate weeds from the field without the use of herbicides. 

Answer: C

Ques. Golden rice is a promising transgenic crop. When released for cultivation, it will help in
(a) producing a petrol-like fuel from rice
(b) alleviation of vitamin A deficiency
(c) pest resistance
(d) herbicide tolerance. 

Answer: B

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

Answer: D

Ques. Golden rice is a transgenic crop of the future with the following improved trait
(a) insect resistance
(b) high lysine (essential amino acid) content
(c) high protein content
(d) high vitamin-A content. 

Answer: D

Ques. The first transgenic crop was
(a) tobacco
(b) cotton
(c) pea
(d) flax. 

Answer: A

Ques. Match the following columns and select the correct option.
      Column-I                                          Column-II
(A) Bt cotton                                       (i) Gene therapy
(B) Adenosine deaminase deficiency      (ii) Cellular defence
(C) RNAi                                             (iii) Detection of HIV infection
(D) PCR                                              (iv) Bacillus thuringiensis
    (A) (B) (C) (D)
(a) (iv) (i) (ii) (iii)
(b) (iii) (ii) (i) (iv)
(c) (ii) (iii) (iv) (i)
(d) (i) (ii) (iii) (iv) 

Answer: A

Ques. Which of the following statements is not correct?
(a) In man insulin is synthesised as a proinsulin.
(b) The proinsulin has an extra peptide called C-peptide.
(c) The functional insulin has A and B chains linked together by hydrogen bonds.
(d) Genetically engineered insulin is produced in E.Coli. 

Answer: C

Ques. Which kind of therapy was given in 1990 to a fouryear-old girl with adenosine deaminase (ADA) deficiency?
(a) Gene therapy
(b) Chemotherapy
(c) Immunotherapy
(d) Radiation therapy

Answer: A

Ques. The two polypeptides of human insulin are linked together by
(a) covalent bond
(b) disulphide bridges
(c) hydrogen bonds
(d) phosphodiester bond. 

Answer: B

Ques. The first human hormone produced by recombinant DNA technology is
(a) insulin
(b) estrogen
(c) thyroxin
(d) progesterone. 

Answer: A

Ques. Which one of the following vectors is used to replace the defective gene in gene therapy?
(a) Adenovirus
(b) Cosmid
(c) Ri plasmid
(d) Ti plasmid

Answer: A

Ques. The first clinical gene therapy was given for treating
(a) diabetes mellitus
(b) chicken pox
(c) rheumatoid arthritis
(d) adenosine deaminase deficiency. 

Answer: D

Ques. Name the Nematode that Infects Roots of Tobacco plant.
a) Meloidegyne incognitia
b) Agarobacterium tumifaciens
c) Bacillus thuringiensis
d) Non of the above

Answer : A

Very Short Answer Type Questions

Question. 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 Immuno Sorbent Assay. It is used for the detection of (HIV) AIDS disease. ELISA is based on the principle of antigen-antibody interaction. Infection by pathogen can be detected by the presence of antigens (proteins, glycoprotieins, etc.) or by detecting the antibodies synthesised by the host against the pathogen.

Question. Name the first transgenic cow. Which gene was introduced in this cow?
Answer : Rosie was the name of first transgenic cow. Gene for human alpha lactalbumin was introduced in its genes, which made the milk nutritionally more balanced than normal cow milk.

Question. PCR is a useful tool for early diagnosis of an infectious disease. Elaborate.
Answer : PCR is a very sensitive technique which enables the 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). Q. 15 What is GEAC and what are its objectives? Answer : GEAC (Genetic Engineering Approval Committee) is an Indian Government Organisation. Its objectives include (i) Examine the validity of Genetic Modification (GM) of organism research. (ii) Inspect the safety of introducing GMO for public services.

Question. Can a disease be detected before its symtoms appear? Explain the principle involved.
Answer : When the symptoms of the disease are not yet visible,the pathogen concentration is very low so, the detection by conventional diagnostic tests is very difficult. However, detection of a disease before the appearance of symptoms is possible by the amplification of victim‘s nucleic acid by PCR. The principle involved here is that a single DNA molecule can be copied endlessly in a test tube using primers, DNA polymerase enzyme and free nucleotides. The desired DNA of the pathogen is amplified by PCR from a limited amount of DNA template.

Question. Give any two reasons why the patent on Basmati should not have gone to an American Company.
Answer : The patent on Basmati should not have gone to an American Company, because of the following reasons (i) The Basmati rice variety has been grown in India since time immemorial. Traditionally, it belongs to India. (ii) The new variety of Basmati that got patent rights to an American Company is actually derived from ‘Indian farmers variety’.

Restriction Enzymes Questions and Answers

 

Ques. 

Name the two strands present in the above matured Insulin.
Answer. A-Polypeptide strand and B-polypeptide strand

Ques. Why insulin is not administer orally to diabetic people?
Answer. It will be digested by protease action in GI tract.

Ques. ELISA is used to diagnose___________.HIV/Malaria/Syphillis/Catract.
Answer. HIV

Ques. In which medium Bt protoxin converted into active toxin and kills bollworm larva?
a)Alkaline
b)Acidic
c)Neutral
d)None of the above.

Answer. a)Alkaline

Ques. Choose the right process for permanent cure of ADA deficiency(SCID).
a)Gene isolate from bone marrow cells producing ADA is introduced into cells at early embryonic stage.
b)Bone Marrow transplantation.
c)Enzyme replacement therapy.
d)None of the above

Answer. a)Gene isolate from bone marrow cells producing ADA is introduced into cells at early embryonic stage.

 

Transgenic Animal and Ethical Issues Questions and Answers

 

Ques. GEAC stands for.
a)Ground Environment Action Committee
b)Genetic Engineering Approval Committee
c)Genetic Engineering Appaisal Committeee
d)Genetic and Environment Approval committee

Answer. b)Genetic Engineering Approval Committee

Ques. The first transgenic cow, Rosie, produced human protein-enriched milk (2.4 grams per litre). The milk contained the human alpha-lactalbumin and was nutritionally a more balanced product for human babies than natural cow-milk.     True/False.
Answer. True

Ques. Transgenic___________ are being used to test the safety of the polio vaccine. Mice/Cat/Tiger/Horse
Answer.  Mice

QUESTIONS

1. Name the technique based on the principle of antigen-antibody interaction used in detection of a virus (HIV).
Answer. ELISA (Enzyme linked immuno - sorbent Assay)

2. Development of a transgenic food crop may help in solving the problem of night blindness in the developing countries, name this crop plant.
Answer. Golden Rice

3. Which nematode infects the roots of tobacco plant and causes a great reduction in yield?
Answer. Meloidegyne incognitia.

4. The first transgenic cow, produced human protein – enriched milk. Name the cow and the protein found in milk.
Answer. Rosie, alpha-lactalbumin

5. The insulin produced using recombinant DNA technology is more advantageous than the insulin extracted from pancreas of slaughtered cattle and pigs. How?
Answer. Insulin obtained from animal source causes allergy.

6. Name two pest resistant plants produced by using recombinant DNA technology.
Answer. Bt Cotton, Bt Corn, Bt Brinjal.

7. What are the two methods for correcting ADA deficiency in a child?
Answer. Bone marrow transplantation having functional ADA enzyme and Enzymereplacement therapy.

8. Some crop plants are modified genetically by manipulating their genes. How are they made beneficial?
Answer. More tolerant to abiotic stresses; pest resistant; reduction in post harvest losses; increased nutritional value of food.

9. GEAC is one of the organisation set up by Indian Government. Write its full form. Give its two objectives.
Answer. GEAC – Genetic Engineering approval committee. Objectives of GEAC are
(i) To make decisions regarding validity of GM research.
(ii) Safety of introducing GMO for public use

10. "Industrialised nations are exploiting the bioresources of under industrialised nations". Justify the statement with a suitable example.
Answer. 
- Industrialised nations are collecting and patenting the genetic resources of under industrialised country like India. An American Company got patent rights on Basmati rice.
- Valuable biomolecules obtained from bioresources are patented and used for commercial purposes.

11. Some multinational companies and other organisations are using bioresources for commercial benefits, without proper authentication and compensation to concerned authorities.
(a) Give the term for this unauthorised act.
(b) Suggest any two ways to get rid of this.
Answer. 
(a) Biopiracy
(b) (i) Benefits of bioresources should be shared between developed and developing nations
(ii) Laws should be developed to prevent unauthorsied exploitation of them bioresources.

12. A bacterium Bacillus thuringiensis produces a toxic protein named ‘cry protein’ that is lethal to certain insects but not to bacterium
(a) Why this toxin does not kill the bacteria?
(b) What type of changes occur in the gut of insects on consuming this protein?
(c) How man has exploited this protein for his benefit?
Answer. 
(a) Produced in inactive form as Prototoxins.
(b) Prototoxin becomes active toxin in alkaline pH of gut of insects. Toxins bind to surface of midgut and cause perforation, swelling, lysis of cells ultimately leading to death.
(c) Specific Bt toxin genes isolated from Bacillus thuringiensis and incorporated into several crop plants such as cotton and corn which become pest resistant against certain insects.

13. Given below is an incomplete flow chart showing the process of production of nematode resistant tobacco plants based on RNAi technique.
(i) Write the missing steps in proper sequence
(ii) At which level RNAi silences the gene?

Answer. 
(i) (b) Using Agrobacterium as a vector, introduced into tobacco
(d) dsRNA (double stranded RNA)
(f) Silenced specific mRNA of the nematode
(g) Parasite could not survive.
(ii) RNAi silences the gene at translation level

LA 

14. The clinical gene therapy is given to a 4 years old patient for an enzyme which is crucial for the immune system to function.

Observe the therapeutical flow chart and give the answer of the following:
(a) Complete the missing steps (B) and (D)
(b) Identify the disease to be cured.
(c) Why the above method is not a complete solution to the problem?
(d) Scientists have developed a method to cure this disease permanently. How?
Answer. 
(a) Step (B) : Lymphocytes are grown in culture medium.
Step (D) : Infusion of genetically engineered lymphocytes into patients.
(b) Adenosine deaminase (ADA) deficiency.
(c) As genetically engineered lymphocytes are not immortal, the patient requires periodic infusion of cells.
(d) If the gene isolated from bone marrow cells producing ADA is introduced into cells at early embryonic stages, it could be a permanent cure.

15. In the given figure, Agrobacterium is utilized for the production of a transgenic crop. Explain the steps a, b, c, d and e shown in the figure.

Answer. Step (a) Plasmid is removed and cut open with restriction endonuclease.
Step (b) Gene of interest is isolated from another organism and amplified using PCR
Step (c) New gene is inserted into plasmid
Step (d) Plasmid is put back into Agrobacterium
Step (e) Agrobacterium based transformation.

16. In the given figure, Form (A) and Form (B) represents different forms of a proteinaceous hormone secreted by pancreas in mammals.
(a) What type of bonding is present between chains of this hormone?
(b) What are these form (A) and form (B). How these forms differ from each other?
(c) Explain how was this hormone produced by Eli Lilly, an American company, using rDNA technology.

Answer. 
(a) Disulphide bonds
(b) Form (A) – Proinsulin
Form (B) – Mature insulin.
Proinsulin contains an extra stretch called C – peptide which is absent in mature insulin.
(c) Eli Lilly company prepared two DNA sequences corresponding to A and
B peptide chains of human insulin and introduced them in plasmid
E. coli to produce insulin chains. Chains A and B were produced separately, extracted and combined by creating disulphide bonds to form insulin.

Important Notes for Class 12 Biology Chapter 12 Biotechnology and Its Application

- Biotechnology is useful to humans in producing various products by using microbes, plants, animals and their metabolic machinery. This became possible due to Recombinant DNA Technology, in which valuable and useful manipulation of genes in various living species is done to obtain desirable products at large scale.
- The applications of biotechnology include therapeutics, diagnostics, Genetically Modified (GM) crops for agriculture, processed food, bioremediation, waste treatment and energy production. Three critical research areas of biotechnology are
(i) To provide the best catalyst in the form of improved organism usually a microbe or a pure enzyme.
(ii) To create optimal conditions through engineering for a catalyst to act.
(iii) Downstream processing technologies to purify the organic compounds or proteins.

Biotechnological Applications in Agriculture

- To feed the increasing population of the world, we need to enhance our food production. This can be done by applying following options
(i) Agrochemical based agriculture
(ii) Organic agriculture
(iii) Genetically engineered crops based agriculture
- The green revolution has succeeded in enhancing the food supply to three folds but yet it was not enough to feed the rapidly growing human population. It has increased the yield of crops mainly due to the use of improved varieties of crops, agrochemicals (fertilisers and pesticides) and better management practices.
- But most of the agrochemicals have harmful effects on the environment and they are expensive for farmers in developing countries. It is also difficult to further increase the yield with existing varieties using conventional breeding. Therefore, the best solution to overcome all these issues is to develop and use GeneticallyModified (GM) crops.

Genetically Modified Organisms (GMOs)

- The plants, bacteria, fungi and animals whose genes have been altered by manipulation are called Genetically Modified Organisms (GMO). These are also called transgenic organisms, as they contain and express one or more foreign genes called transgenes. GM plants are useful in many ways.
- Genetic modification has done the following changes to the phenotypic expression of the plants
(i) Crops became more tolerant to abiotic stresses like cold, drought, salt and heat.
(ii) Dependence on chemical pesticides has reduced, i.e. pest-resistant crops.
(iii) It helped to reduce post-harvest losses.
(iv) Efficiency of mineral usage increased in plants, preventing early exhaustion of fertility of soil.
(v) Enhanced nutritional value of food, e.g. vitamin-A enriched rice (golden rice).
Other than the above mentioned uses, genetic modifications have been used to create tailor-made plants to supply alternative resources to the industries in the form of starches, fuels and pharmaceuticals.

Biopesticides
An application of biotechnology in agriculture is the production of pest-resistant plants which could decrease the amount of pesticides being used. Bt toxin is produced by a
bacterium called Bacillus thuringiensis.
Bt toxin gene has been cloned from the bacteria and been expressed in plants to provide resistance to the insects without the need for insecticides and so named as biopesticide, e.g. Bt cotton, Bt corn, rice, tomato, potato and soybean, etc.

Bt Cotton
- Bt cotton is created by using some strains of bacterium, Bacillus thuringiensis (Bt is a short form). This bacterium produces a protein that kills certain insects such as lepidopterans (tobacco budworm, armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes).
- Bacillus thuringiensis forms protein crystals (Cry) during a particular phase of their growth. These crystals contain a toxic insecticidal protein. But this toxin does not kill the Bacillus (bacterium), because Bt toxin protein exists as inactive protoxins but once an insect ingests the inactive toxin, it is converted into its active form due to the alkaline pH of the gut which solubilises the crystals.
- The activated toxin binds to the surface of midgut epithelial cells and creates pores that cause cell swelling and lysis leading to the death of an insect. Bt tobacco was first cultured to kill hornworm (Manduca sexta). The toxin is encoded by the cry genes, which are insect group specific.
- For example,
(i) cry IAc and cry IIAb control cotton bollworms.
(ii) cry IAb controls corn borer.
(iii) cry IIIAb controls colorado potato beetle.
(iv) cry IIIBb controls corn rot worm.

Biotechnological Applications in Medicine

- The recombinant DNA technological processes have made immense impact in the area of healthcare by enabling mass production of safe and more effective therapeutic drugs.
- The recombinant therapeutics do not induce unwanted immunological responses as in common case of similar products isolated from non-human sources.
- At present, about 30 recombinant therapeutics have been approved for human use all over the world. Out of these, 12 are marketed in India.

Genetically Engineered Insulin

- It has lead to sufficient availability of insulin for the management of adult onset diabetes. Insulin used for diabetes was earlier extracted from the pancreas of slaughtered cattle and pigs. This insulin developed allergy or other types of reactions due to the foreign protein.
- Insulin consists of two short polypeptide chains, i.e. chain ‘A’ and chain ‘B’ that are linked together by disulphide bridges.
- In mammals, including humans, insulin is synthesised as a pro-hormone (needs to be processed before it becomes a fully mature and functional hormone) which contains an extra stretch called the C-peptide.
- This C-peptide is not present in the mature insulin and is removed during maturation into insulin. Therefore, the main challenge for the production of insulin using rDNA techniques was getting insulin assembled into a mature form.

- In 1983, Eli Lilly, an American company prepared two DNA sequences corresponding to A and B-chains of human insulin and introduced them in plasmids of E. coli to produce insulin chains. These chains (A and B) were produced separately, extracted and combined by creating disulphide bonds to form human insulin called humulin.

Recombinant Vaccine

- Vaccines produced through genetic engineering methods are called recombinant vaccines or second generation vaccines.
- They have gene inserts for the surface proteins of a pathogen which enhance immunity but do not result in infection.
- These plasmids are inserted in bacteria or yeast cells that express the viral proteins which are then injected into the human host as vaccine. There they are recognised as  foreign and an immune response is elicited.
- Recombinant hepatitis-B vaccine and polio vaccine are the examples of rDNA vaccine.

Stem Cell Technology

- It is now known to be the most rapidly developing field that combines the efforts of cell biologists and geneticists for the treatment of a variety of malignant and non-malignant diseases by using stem cells.
- Stem cells are undifferentiated biological cells that can differentiate into specialised cells and can divide (through mitosis) to produce more stem cells. These cells are found in multicellular organisms.
- They are mainly of two types, i.e. embryonic stem cells, which are isolated from the inner cell mass of blastocysts and adult stem cells, which exist throughout the body after embryonic development and are found inside different types of tissues such as brain.
- The potential applications of stem cell include organ and tissue regeneration, bone marrow transplantation, brain disease treatment, cell deficiency therapy, cardiovascular disease treatment, blood disease treatment, etc.

Gene Therapy

- It is a collection of methods which allow correction of gene defects, diagnosed in a child or an embryo. It involves replacing a defective mutant gene with a functional gene. It works effectively against single gene disorders, enzymatic disorders and immunodeficiency disorders.
- The first gene therapy was performed in a 4 years old girl in 1990, who had Adenosine Deaminase (ADA) deficiency. The enzyme, adenosine deaminase is crucial for the immune system to function.
- The disorder is caused due to the deletion of the gene for adenosine deaminase.
- In some children, ADA deficiency can be cured by bone marrow transplantation and in, others by enzyme replacement therapy. But, the problem with both of these approaches is that they are not completely curative. This is why gene therapy was introduced to cure this ailment.
- Steps followed in enzyme replacement gene therapy are given below
– In first step of 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 subsequently returned to the patient.
– As these cells are not immortal, the patient requires periodic infusion of such genetically engineered lymphocytes. But if the gene isolated from marrow cells producing ADA is introduced into cells at early embryonic stages, it could be a permanent cure.
- Some other diseases that can be treated by gene therapy are haemophilia, cystic fibrosis, Parkinson’s disease, etc.

Transgenic Animals

These are the animals which have their DNA manipulated to possess and express an extra (foreign) gene. Examples are transgenic rats, rabbits, pigs, sheep, etc. Out of all the existing transgenic animals, 95% are mice.

Several benefits and uses of transgenic animals are

1. Normal physiology and development Transgenic animals can be specifically designed to allow the study of how genes are regulated and how they affect the normal functioning of the body and its development. For example, the study of complex factors involved in growth such as insulin like growth factors.

2. Study of disease Many transgenic animals are designed to increase the understanding of how genes contribute to the development of diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s. These are specially made to serve as models for human diseases, so that investigation of new treatments for diseases is made possible.

3. Biological products Human diseases can be treated by medicines that contain biological products.
(i) Transgenic animals that produce useful biological products can be created by the introduction of the portion of the DNA or genes that code for a particular product such as human protein (a-1-antitrypsin) which is used to treat emphysema. Similar attempts are being made for the treatment of Phenylketonuria (PKU) and cystic fibrosis.

(i) Transgenic animals that produce useful biological products can be created by the introduction of the portion of the DNA or genes that code for a particular product such as human protein (a-1-antitrypsin) which is used to treat emphysema. Similar attempts are being made for the treatment of Phenylketonuria (PKU) and cystic fibrosis.

4. Vaccine safety Transgenic mice are being used for testing the safety of vaccines before they are used on humans, e.g. polio vaccine. If found reliable and successful they could replace the use of monkeys in order to test the safety of batches of the vaccine.

5. Chemical safety testing It is also known as toxicity or safety testing. It is similar to the procedure used for testing toxicity of drugs.
Transgenic animals are made that carry the genes, which make them more sensitive to toxic substances than the non-transgenic animals. They are then exposed to toxic substances and effects are studied. This allows us to obtain result in less time.

Ethical Issues

– Manipulation of living organisms by human race can be unethical and should not go unregulated. The genetic modification of organisms can have unpredictable results, when such organisms are introduced into the ecosystem.
– The modification or usage of living organisms for public services has also created problems with patents granted for the same.
– Therefore, there is a need for some ethical standards to evaluate our actions. These sets of standards that are used to regulate our activities in relation to biological world are called bioethics.
– Public is very much concerned that certain companies are being granted patents for the products and technologies that make use of the genetic materials, plants and other biological resources that have long been developed by the farmers and indigenous people of a specific region/country.
– In order to control these issues, Indian Government has setup an organisation Genetic Engineering Approval Committee (GEAC) which makes all decisions regarding the
validity of GM research and the safety of introducing GMOs for public services.

Patent
It is a set of exclusive rights granted by a government to the inventors or their assignee to prevent others from commercial use of their invention. And when patent is granted for biological entities and for products derived from them, they are called biopatents. Primarily USA, Japan and members of European Union are awarding biopatents.

Biopiracy
– It refers to use of bioresources by multinational companies and other organisations without proper authorisation from the countries or people concerned without any payment.
– Some nations are developing laws to prevent such unauthorised exploitation of their bioresources and traditional knowledge.
– The Indian Parliament has recently cleared the second amendment of the Indian Patents Bill that takes such issues of biopiracies into consideration including patent terms, emergency provisions and research anddevelopment initiative.

Controversies in India Regarding Biopatent and Biopiracy

When a patent is taken on plants and seeds derived from Indian biological resources, biopiracy occurs. Challenging and stopping such biopiracy is the duty of government. Following are the plants on which controversies occurred in India Basmati Rice

– Rice is being used since thousands of years in Asia’s agricultural history, of which 2,00,000 varieties are in India alone.
– Basmati is unique for its aroma and flavour, whose 27 varieties are cultivated in India. An American company Rice Tec won a patent on Basmati Rice Lines and Grains in 1997 through the US Patent and Trademark Office and was allowed to sell a ‘new variety’ in US and Abroad.
– This new variety of Basmati was actually derived from the Indian farmer’s varieties.
– Indian Basmati was crossed with semi-dwarf varieties and claimed as an invention or a novelty by the American company. The patent extends to functional equivalents implying that other people selling Basmati rice could be restricted by the patent.

Turmeric and Neem
– In May 1995, the US Patent Office granted to the University of Mississippi Medical Center a patent for ‘Use of Turmeric in Wound Healing’.
– In 1996, another patent was granted to the firm of WR Grace and Co., by the European Patent Office,Munich for ‘fungicidal uses of neem oil’.
– Thus, if we do not pay attention or counter these patent applications, our rich legacy will be encashed by other countries and individuals.