Solubilises the Protein Toxin Crystals (D) All of the Above

Physics

1. Study the following statements regarding Bt toxins produced by bacterium Bacillus thuringiensis and select the correct one

(a) Most strains of Baclillus thuringiensis prodcuce proteins that kill certain insects such as lepidopterans, coleopterans and

dipterans

(b) Bt toxin proteins do not kill the bacteria themselves because the toxin proteins occur in an inactive form called protoxins

(c) When an insect ingests the inactive Bt toxin, it is converted to an active form of toxin due to alkaline pH of the gut which

solubilises the protein toxin crystals (d) All of the above

2. ‘Flavr Savr’ variety of tomato which remains fresh for a longer period than normal tomato variety

(a) has higher amount of enzyme polygalacturonase (b) has reduced amount of enzyme polygalacturonase

3. Which of the following genes were introduced in cotton to protect it from cotton bollworms?

(a) Cry Ac and Cry Ab (b) Bt Ac and Bt Ab (c) Cry IAc and Cry II Ab (d) Nif genes

4. All are the biotechnological applications in order to increase food production except

(a) apiculture (b) agro-chemical based agriculture (c) organic farming

(d) genetically engineered crop-based agriculture

5. Which of the following statements is not correct regarding the genetic modification of crops?

(a) It makes crops more tolerant to abiotic stresses (b) It results in decreased efficiency of mineral usage by plants

6. What causes the inactive form of Bt toxin i.e. protoxin to get converted into its active form in the body of an insect?

(a) Temperature of the gut (b) Enzymes present in the saliva (c) Alkaline pH of the gut

(d) There is no specific reason

7. Bt toxins are

(a) intracellular lipids (b) intracellular crystalline proteins (c) extracelluar crystalline proteins

(d) intracellular polysaccharides

8. ‘Nif’ gene for nitrogen fixation in cereal crops like wheat, jowar etc. is introduced by cloning

(a) Rhizobium meliloti (b) Bacilus thuringiensis (c) Rhizopus stolonifer (d) Agrobacterium tumefacie

9. Select the correct statement regarding an improved variety of transgenic basmati rice i.e. golden rice.

(a) It does not require the use of chemical fertilizers (b) It is completely resistant to all insect pests and diseases

10. Hirudin is

(a) a protein produced by Hordeum vulgare, which is rich in lysine

(b) a toxic molecule isolated from Gossypium hirsutum, which reduces human fertility

(d) an antibiotic produced by a genetically engineered bacterium Escherichia coil

11. A transgenic food crop which may help in solving the problem of night blindness in developing countries is

(a) Bt cotton (b) golden rice (c) flavr savr (d) Bt corn

12. First genetically modified plant commercially released in India is

(a) golden rice (b) flavr savr (c) Bt-brinjal (d) Bt-cotton

13. DNA fingerprinting refers to

(a) molecular analysis of profiles of DNA samples (b) analysis of DNA samples using imprinting devices

(d) techniques used for identification of fingerprints of individuals

14. Which of the following statements is not correct?

(a) Most Bt toxins are insect group specific

(b) RNAi takes place in all eukaryotic as well as prokaryotic organisms as a method of cellular defense

(d) Adult-onset diabetes can be controlled by taking insulin at regular time intervals

15. Technique used to detect the DNA in a clone is

(a) polymerase chain reaction (b) gel electrophoresis (c) chromatography (d) autoradiography

16. Which of the following companies started selling humulin in the year 1983?

(a) Eli Lilly (b) Genetech (c) GEAC (d) None of these

17. Gene therapy can be referred to as

(a) pre-clinical testing for inherited diseases in newborns (b) treatment of diseases caused by genetic defect

18. Human insulin is being commercially produced from a transgenic species of

(a) Mycobacterium (b) Rhizobium (c) Saccharomyces (d) Escherichia

19. For effective treatment of disease

(a) early diagnosis is required but understanding of its pathophysiology is not required

(b) early diagnosis is not required but understanding of its pathophysiology is required

(d) neither early diagnosis nor understanding of its pathophysiology is required

20. Second generation vaccines are prepared by recombinant DNA technology. Which out of the following are the examples of such vaccines?

(a) Heptitis B virus vaccine (b) Herpes virus vaccine (c) Salk’s polio vaccine (d) Both (a) and (b)

21. Animals that have their DNA manipulated to possess and express a foreign gene are called

(a) transgeneic animals (b) somatic hybrids (c) somaclones (d) super animals

22. Dolly sheep was genetically similar to

(a) the mother from which enucleated egg cell was taken (b) the mother from which nucleated udder cell was taken

23. Genetic engineering has been successfully used for producing

(a) transgenic mice for testing safety of polio vaccine before use in humans

(b) transgenic coq-Rosie which produces high fat milk for making ghee

24. The organization which makes decisions regarding the validity of GM research and the safety of introducing GM-organisms for public services is

(a) Genetic Engineering Approval Committee (b) Genome Environment Action Committee

25. Use of bio-resources by multinational companies and other organizations without proper authorization from the countries and people concerned without compensatory payment is termed as

(a) resource partitioning (b) biopracy (c) patenting (d) biofortification

26. Which Indian plants have either been patented or attempts have been made to patent them by western nations for their commercial use?

(a) Basmati rice (b) Turmeric (c) Neem (d) All of these have been targeted

27. Biopatents are

(i) right to use invention (ii) right to use biological entities (iii) right to use products (iv) right to use process

(a) (i) and (ii) (b) (ii) only (c) (i), (ii) and (iv) (d) (i), (ii), (iii) and (iv)

28. Which of the following statements is correct?

(a) The current interest in the manipulation of microbes, plants and animals has raised serious ethical issues

(b) One possible risk of genetic engineering is the accidental production of antibiotic resistant microorganisms

(d) All of these

29. Which of the following statements is correct regarding Genetic Engineering Approval committee (GEAC)?

(a) It makes decision regarding the validity of GM research

(b) It ensures the safety of introducing GM-organisms for public services

(c) Genetic modification of organisms can have unpredictable results when such organisms are introduced into the ecosystem.

Therefore, the Indian government has set up organization such as GEAC (d) All of these

30. Bacteria genetically engineered to express a gene from a plant will

(a) Synthesize a protein with the same sequence of amino acids as in the plant and, therefore, the protein will have the same

structure and function as in the plant

(b) synthesize a protein with essentially the same sequence of amino acids as in the plant with differences relating to different codon

Wobble rules between prokaryotes and eukaryotes

(d) not be able to synthesize a protein because translation is coupled with transcription and post-transcriptional processing does not

occur in it

Solutions

1. (d)Soil bacterium Bacillus thuringiensis (Bt) produces proteins that kill certain insects like lepidopterans (tobacco budworm,

armyworm), coleopterans (beetles) and dipterans (flies, mosquitoes). Bacillus thuringiensis forms some intracellular protein crystals.

These crystals contain a toxic insecticidal protein. The Bt toxin protein exists as inactive toxin and is converted into an active form

due to the alkaline pH of the alimentary canal that solubilizes the crystals. The activated toxin binds to the surface of midgut

epithelial cells and finally cause death of the insect.

2. (b) The tomato variety ‘Flavr Savr’ presents an example where expression of a native tomato gene has been blocked. Fruits

softening is promoted by the enzyme polygalacturonase, which degrades pectin. Production of polygalacturonase is blocked in the

transgenic tomato variety ‘Flavr Savr’. So, fruits of this tomato variety remain fresh and retain their flavor much longer than do the

fruits of normal tomato varieties. Additionally, the fruits have a superior taste and increased total soluble solids.

3. (c) Two cry genes, cry IAc and cry IIAb have been incorporated in cotton. The genetically modified crop is called Bt cotton as it

contains Bt toxin genes. The genes cry I Ac and cry II Ab control cotton bollworms.

4. (a) Rearing of honey bees for obtaining honey and bee wax is called apiculture. It is not a biotechnological application.

5. (b) 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 usuage by plants (this prevents early exhaustion of fertility of soil)

(v) Enhanced nutritional value of food, e.g., Vitamin ‘A’ enriched rice

In addition to these uses, GM has been used to create tailor-made plants to supply alternative resources to industries, in the form of

starch, fuels and pharmaceuticals .

6. Refer answer 1

7. Refer answer 1

8. (a)

9. (d) Rice is a staple food in many countries, particularly in Asia, but does not contain vitamin A or its immediate precursors. By

inserting two genes from Daffodil and one gene from a bacterial species into rice plants, Swiss researchers have produced rice

capable of synthesizing b-caratene the precursor of vitamin A. This rice is called ‘Golden rice’ because of yellow colour of rice grains

due to the presence of b-caratone.

10. (c) Hirduin is a protein that stops blood clotting. The gene encoding hirduin was chemically synthesized. This gene was then

transferred into Brassica napus, where hirduin accumulates in seeds. The hirduin is purified and used as medicine.

11. Refer answer 10

12. (d) The Government has agreed to allow cultivation of genetically modified Bt Cotton. Bt cotton farming has shown good results in

Malwa region in Punjab.

13. (a) DNA fingerprinting (DNA typing or DNA profiling) is a technique of determining nucleotide sequence of certain areas of DNA

which are unique to each individual. Important for DNA fingerprinting are short nucleotide repeats that vary in number from person to

person, but are inherited. These are the Variable Number of Tandem Repeats or VNTRs. The VNTRs of two persons may be of the

same length and sequence at certain sites, but vary at others.

14. (a) RNAi or RNA interference takes place in all eukaryotic organisms as a method of cellular defense. This method involves silencing

of a specific mRNA. Using Agrobacterium vectors, nematode specific genes are introduced into the host plant (tobacco plant). The

introduction of DNA was such that it produced both sense and anti-sense RNA in the host cells. These two RNAs being

complementary to each other formed a dsRNA (double stranded RNA) that initiated RNAi.

15. (d) A single stranded DNA or RNA joined with a radioactive molecule (probe) is allowed to hybridize to its complementary DNA in a

clone of cells. It is followed by detection using autoradiography. The clone having the mutated gene will not appear on the

photographic film, because the probe will not have the complementarity with the mutated gene.

16. (a) In 1983 , Eli Lilly an American company, first prepared two DNA sequences corresponding to A and B chains of human insulin

and introduced them in plasmids of Escherichia coli to produce insulin chains. Chains A and B were produced separately, extracted

and combined by creating disulfide bonds to form human insulin (humulin).

17. (b) Gene therapy is a collection of methods that allows correction of gene defect that has been diagnosed in a child/embryo.

Correcting of a genetic defect involves delivery of a normal gene into the individual or embryo to take over the function of and

compensate for the non-functional gene.

18. (d) Refer answer 58

19. (c) For effective treatment of a disease , early diagnosis and understanding its pathophysiology is very important. Using conventional methods of diagnosis (serum and urine analysis, etc.) early detection is not possible. Recombinant DNA technology, Polymerase Chain Reaction (PPCR) and Enzyme Linked Immuno-sorbent Assay (ELISA) are some of the techniques that serve the purpose of early diagnosis.

20. (d) Second generation vaccines are the vaccines which are prepared by recombinant DNA technique/genetic engineering. E.g.,

Hepatitis B virus vaccine, Herpes virus vaccine and Pneumonia vaccine. The yeast-derived recombinant hepatitis B virus vaccine is

the first commercially available human vaccine produced by the genetic engineering technology. Hepatitis B vaccine is produced

from transgenic yeast by recombinant DNA technology.

21. (a) The animals which carry foreign genes are called transgenic animals. The foreign genes inserted into the genome of the animal

using recombinant DNA technology are called transgenes.

22. (b) Dolly, the sheep, was cloned in 1997. Ian Wiutand his colleagues at the Roslin Research Institute in Scotland, took cells from

ewe (mother sheep’s udder) . They stored these udder cells in low nutrient culture. This stopped the starved cells from dividing (G0

phase)and switched off their active genes. One complete udder cell with its nucleus was selected, because its nucleus carries the