1. Introduction of food plants developed by genetic engineering is not desirable because
(a) economy of developing countries may suffer
(b) these products are less tasty as compared to the already existing products
(c) this method is costly
(d) there is danger of entry of viruses and toxins with introduced crop
2. Gel electrophoresis is used for
(a) cutting of DNA into fragments
(b) separation of DNA fragments according to their size
(c) construction of recombinant DNA by joining with cloning vectors
(d) isolation of DNA molecule
3. The linking of antibiotic resistance gene with the plasmid vector became possible with
(a) DNA ligase
(b) Endonucleases
(c) DNA polymerase
(d) Exonucleases
4. Polyethylene glycol method is used for
(a) biodiesel production
(b) seedless fruit production
(c) energy production from sewage
(d) gene transfer without a vector
5. Select the correct statement from the following?
(a) Biogas is produced by the activity of aerobic bacteria on animal waste
(b) Methanobacterium is an aerobic bacterium found in rumen of cattle
(c) Biogas, commonly called gobar gas, is pure methane
(d) Activated sludge-sediment in settlement tanks of sewage treatment plant is a rich source of aerobic bacteria
6. Which one of the following is used as vector for cloning genes into higher organisms?
(a) Baculovirus
(b) Salmonella typhimurium
(c) Rhizopusnigricans
(d) Retrovirus
7. Which one of the following palindromic base sequences in DNA can be easily cut at about the middle by some particular restriction enzyme?
(a) 5’………….CGTTCG………….3′
3’………….ATGGTA………….5′
(b) 5’………….GATATG………….3′
3’………….CTACTA………….5′
(c) 5’………….GAATTC………….3′
3’………….CTTAAG………….5′
(d) 5’………….CACGTA………….3′
3’………….CTCAGT………….5′
8. DNA or RNA segment tagged with a radioactive molecule is called
(a) Vector
(b) Probe
(c) Clone
(d) Plasmid
9. Restriction endonucleases are enzymes which
(a) make cuts at specific positions within the DNA molecule
(b) recognize a specific nucleotide sequence for binding of DNA ligase
(c) restrict the action of the enzyme DNA polymerase
(d) remove nucleotides from the ends of the DNA molecule
10. There is a restriction endonuclease called EcoRI. What does .co. part in it stand for?
(a) colon
(b) coelom
(c) coenzyme
(d) coli
11. Agarose extracted from sea weeds finds use in:
(a) Spectrophotometry
(b) Tissue culture
(c) PCR
(d) Gel electrophoresis
12. Bacillus thuringiensis forms protein crystals which contain insecticidal protein.
(a) binds with epithelial cells of midgut of the insect pest ultimately killing it
(b) is coded by several genes including the gene cry
(c) is activated by acid pH of the foregut of the insect pest.
(d) does not kill the carrier bacterium which is itself resistant to this toxin
14. Which one of the given options correctly identifies its certain component (s)?
(a) ori – original restriction enzyme
(b) rop-reduced osmotic pressure
(c) Hind III, EcoRI – selectable markers
(d) ampR, tetR – antibiotic resistance genes
15. PCR and Restriction Fragment Length Polymorphism are the methods for:
(a) Study of enzymes
(b) Genetic transformation
(c) DNA sequencing
(d) Genetic Fingerprinting
16. A single strand of nucleic acid tagged with a radioactive molecule is called:
(a) Vector
(b) Selectablemarker
(c) Plasmid
(d) Probe
17. Which one is a true statement regarding DNA polymerase used in PCR
(a) It is used to ligate introduced DNA in recipient cell
(b) It serves as a selectable marker
(c) It is isolated from a virus
(d) It remains active at high temperature
18. For transformation, micro-particles coated with DNA to be bombarded with gene gun are made up of:
(a) Silver or Platinum
(b) Platinum or Zinc
(c) Silicon or Platinum
(d) Gold or Tungsten
19. Biolistics (gene-gun) is suitable for
(a) DNA finger printing.
(b) Disarming pathogen vectors.
(c) Transformation of plant cells.
(d) Constructing recombinant DNA by joining with vectors.
20. In genetic engineering, the antibiotics are used
(a) as selectable markers.
(b) to select healthy vectors.
(c) to keep the cultures free of infection.
(d) as sequences from where replication starts.
21. The figure below shows three steps (A, B, C) of Polymerase Chain Reaction (PCR). Select the option giving correct identification together with what it represents?
(a) B – Denaturation at a temperature of about 98°C separating the two DNA strands.
(b) A – Denaturation at a temperature of about 50°C.
(c) C – Extension in the presence of heat stable DNA polymerase.
(d) A – Annealing with two sets of primers.
22. Which one of the following represents a palindromic sequence in DNA?
(a) 5′ – GAATTC – 3′ 3′ – CTTAAG – 5′
(b) 5′ – CCAATG – 3′ 3′ – GAATCC – 5′
(c) 5′ – CATTAG – 3′ 3′ – GATAAC – 5′
(d) 5′ – GATACC – 3′ 3′ – CCTAAG – 5′
23. DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by:
(a) Polymerase chain reaction
(b) Electrophoresis
(c) Restriction mapping
(d) Centrifugation
24. The colonies of recombinant bacteria appear white in contrast to blue colonies of nonrecombinantbateria because of:
(a) Insertional inactivate of alphagalctosidase in non – recombinant
(b) Insertional inactivation of alphagalactosidase in recombinant bacteria
(c) Inactivation of glycosidase enzyme in recombinant bacteria
(d) Non-recombinant bacteria containing beta-galactosidase
25. Genes of interest can be selected from a genomic library by using
(a) Restriction enzymes
(b) Cloning vectors
(c) DNA probes
(d) Gene targets
26. Restriction endonucleases are used in genetic engineering because
(a) They can degrade harmful proteins
(b) They can join DNA fragments
(c) They can cut DNA at specific base sequences
(d) They can cut DNA at variable sites
26. A gene whose expression helps to identify transformed cell is known as
(a) structural gene
(b) selectable marker
(c) vector
(d) plasmid
27. An example of gene therapy is
(a) production of injectable hepatitis B vaccine.
(b) production of vaccines in food crops like potatoes which can be eaten.
(c) introduction of gene for adenosine deaminase in persons suffering from Severe Combined Immuno Deficiency (SCID).
(d) production of test tube babies by artificial insemination and implantation of fertilized eggs.
28. Introduction of foreign genes into plant or animal cells using micropipettes is
(a) Electroporation
(b) microinjection
(c) Chemical – mediated genetransfer
(d) Particle gun
29. The process of separation and purification of expressed protein before marketing is called
(a) postproduction processing
(b) upstream processing.
(c) downstream processing
(d) bioprocessing
30.The polymerase chain reaction (PCR) technology was discovered by
(a) Craig Venter
(b) axam and Gilbert
(c) Karry Mullis
(d) Saiki et al
31. Which of the following is not a component of downstream processing?
(a) Preservation
(b) Purification
(c) Separation
(d) Expression
32. Restriction endonucleases are used as
(a) molecular knives for cutting DNA at specific sites
(b) molecular cement to combine DNA sites.
(c) molecular build up at nucleotides.
(d) molecular degradation to DNA breakup.
33. The Taq polymerase enzyme is obtained from
(a) Thermus aquaticus
(b) Thiobacillus ferroxidans.
(c) Bacillus subtilis
(d) Pseudomonas putida
34.Genetic engineering is possible, because
(a) the phenomenon of transduction in bacteria is well understood
(b) we can see DNA by electron microscope
(c) We can cut DNA at specific sites by endonucleases like DNAs
(d) restriction endonucleases purified from bacteria can be used in vitro
35. Which of the following is not required for any of the techniques of DNA fingerprinting available at present?
(a) Polymerase chain reaction
(b) Zinc finger analysis
(c) Restriction enzymes
(d) DNA- DNA hybridisation
36. An analysis of chromosomal DNA using the Southern hybridization technique does not use
(a) autoradiography
(b) electrophoresis
(c) blotting
(d) PCR
37. Two bacteria found to be very useful in genetic engineering experiments are
(a) Nitrosomonas and Klebsiella
(b) Escherichia and Agrobacterium
(c) Nitrobacter and Azotobacter
(d) Rhizobium and Diplococcus
38. A single strand of nucleic acid tagged with a radioactive molecule is called
(a) vector
(b) selectable marker
(c) plasmid
(d) probe.
39. The sequence of DNA that reads the same backward and forward across the double strand is……..
(a) Recipient sequence
(b) palindromic sequence
(c) Replicate sequence
(d) origin sequence
40. During the process of isolation of DNA, chilled ethanol is added to
(a) facilitate action of restriction enzymes
(b) remove proteins such as histones
(c) precipitate DNA
(d) break open the cell to release DNA
41. PCR and restriction fragment length polymorphism are the methods for
(a) genetic fingerprinting
(b) study of enzymes
(c) genetic transformation
(d) DNA sequencing
42. Biolistics (genegun) is suitable for
(a) disarming pathogen vectors
(b) DNA fingerprinting
(c) transformation of plant cells
(d) constructing recombinant DNA by joining with vectors
43. There is a restriction endonuclease called EcoRI. What does “co” part in it stand for?
(a) coenzyme
(b) colon
(c) coelom
(d) coli
44. Which of the following are used in gene cloning?
(a) Mesosomes
(b) Plasmids
(c) Nucleoids
(d) Lomasomes
45. The DNA fragments separated on an agarose gel can be visualised after staining with :
(a) Acetocarmine
(b) Aniline blue
(c) Ethidium bromide
(d) Bromophenol blue
46. The process of separation and purification of expressed protein before marketing is called :
(a) Downstream processing
(b) Bioprocessing
(c) Postproduction processing
(d) Upstream processing
47. DNA fragments are:
(a) Negatively charged
(b) Neutral
(c) Either positively or negatively charged depending on their size
(d) Positively charged
48. A gene whose expression helps to identify transformed cell is known as :
(a) Vector
(b) Plasmid
(c) Structural gene
(d) Selectable marker
49. What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis ?
(a) The smaller the fragment size, the farther it moves
(b) Positively charged fragments move to farther end
(c) Negatively charged fragments do not move
(d) The larger the fragment size, the farther it moves
50. Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes?
(a) Retrovirus
(b) Ti plasmid
(c) pBR 322
(d) l phage
51. Use of bioresources by multinational companies and organisations without authorisation from the concerned country and its people is called
(a) Bio-infringement
(b) Biopiracy
(c) Bioexploitation
(d) Biodegradation
52. In India, the organisation responsible for assessing the safety of introducing genetically modified organisms for public use is
(a) Indian Council of Medical Research (ICMR)
(b) Council for Scientific and Industrial Research (CSIR)
(c) Genetic Engineering Appraisal Committee (GEAC)
(d) Research Committee on Genetic Manipulation (RCGM)
53. The correct order of steps in Polymerase Chain Reaction (PCR) is
(a) Extension, Denaturation, Annealing
(b) Annealing, Extension, Denaturation
(c) Denaturation, Annealing, Extension
(d) Denaturation, Extension, Annealing
54. A ‘new’ variety of rice was patented by a foreign company, though such varieties have been present in India for a long time. This is related to
(a) Co-667
(b) Sharbati Sonora
(c) Basmati
(d) Lerma Rojo
55. Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes?
(a) BOD incubator
(b) Sludge digester
(c) Industrial oven
(d) Bioreactor
56. DNA precipitation out of a mixture of biomolecules can be achieved by treatment with
(a) Isopropanol
(b) Chilled ethanol
(c) Methanol at room temperature
(d) Chilled chloroform
57. Following statements describe the characteristics of the enzyme Restriction
Endonuclease. Identify the incorrect statement.
(a) The enzyme cuts DNA molecule at identified position within the DNA.
(b) The enzyme binds DNA at specific sites and cuts only one of the two strands.
(c) The enzyme cuts the sugar-phosphate backbone at specific sites on each strand.
(d) The enzyme recognizes a specific palindromic nucleotide sequence in the DNA
58. Which of the following is true for Golden rice?
(a) It is Vitamin A enriched, with a gene from daffodil
(b) It is pest resistant, with a gene from Bacillus thuringiensis
(c) It is drought tolerant, developed using Agrobacterium vector
(d) It has yellow grains, because of a gene introduced from a primitive variety of rice
59. What triggers activation of protoxin to active Bt toxin of Bacillus thuringiensis in boll worm?
(a) Body temperature
(b) Moist surface of midgut
(c) Alkaline pH of gut
(d) Acidic pH of stomach
60. The sequence that controls the copy number of the linked DNA in the vector, is termed
(a) Palindromic sequence
(b) Recognition site
(c) Selectable marker
(d) Ori site
61. The specific palindromic sequence which is recognized by EcoRI is
(a) 5’ – CTTAAG – 3’
3’ – GAATTC – 5’
(b) 5’ – GGATCC – 3’
3’ – CCTAGG – 5’
(c) 5’ – GAATTC – 3’
3’ – CTTAAG – 5’
(d) 5’ – GGAACC – 3’
3’ – CCTTGG – 5’
62. In gel electrophoresis, separated DNA fragments can be visualized with the help of
(a) Acetocarmine in UV radiation
(b) Ethidium bromide in infrared radiation
(c) Acetocarmine in bright blue light
(d) Ethidium bromide in UV radiation
63. Choose the correct pair from the following
(a) Nucleases – Separate the two strands of DNA
(b) Exonucleases – Make cuts at specific positions within DNA
(c) Ligases – Join the two DNA molecules
(d) Polymerases – Break the DNA into fragments
64. Ray florets have
(a) Hypogynous ovary
(b) Half inferior ovary
(c) Inferior ovary
(d) Superior ovary
65. Identify the wrong statement with regard to Restriction Enzymes.
(a) They are useful in genetic engineering.
(b) Sticky ends can be joined by using DNA ligases.
(c) Each restriction enzyme functions by inspecting the length of a DNA sequence.
(d) They cut the strand of DNA at palindromic sites.
66. 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)
(1) (ii) (iii) (iv) (i)
(2) (i) (ii) (iii) (iv)
(3) (iv) (i) (ii) (iii)
(4) (iii) (ii) (i) (iv)
67. Which of the following statements is not correct?
(a) The functional insulin has A and B chains linked together by hydrogen bonds.
(b) Genetically engineered insulin is produced in E.Coli.
(c) In man insulin is synthesised as a proinsulin
(d) The proinsulin has an extra peptide called C-peptide.
68. Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is resistant to
(a) Plant nematodes
(b) Insect predators
(c) Insect pests
(d) Fungal diseases
69. Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction)?
(a) Annealing, Denaturation, Extension
(b) Denaturation, Annealing, Extension
(c) Denaturation, Extension, Annealing
(d) Extension, Denaturation, Annealing
70. During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out :
(a) Polysaccharides
(b) RNA
(c) DNA
(d) Histones
71. When gene targetting involving gene amplification is attempted in an individual’s tissue to treat disease, it is known as :
(1) Safety testing
(2) Biopiracy
(3) Gene therapy
(4) Molecular diagnosis
72. Match List-I with List-II
| List I | List II | ||
| (a) | Protoplast fusion | (i) | Totipotency |
| (b) | Plant tissue culture | (ii) | Pomato |
| (c) | Meristem culture | (iii) | Somaclones |
| (d) | Micropropagation | (iv) | Virus free plants |
Choose the correct answer from the options given below.
(a) (b) (c) (d)
(1) (iv) (iii) (ii) (i)
(2) (iii) (iv) (ii) (i)
(3) (ii) (i) (iv) (iii)
(4) (iii) (iv) (i) (ii)
73. Which of the following is not an application of PCR (Polymerase Chain Reaction)?
(a) Detection of gene mutation
(b) Molecular diagnosis
(c) Gene amplification
(d) Purification of isolated protein
74. Plasmid pBR322 has Pstl restriction enzyme site within gene ampR that confers ampicillin resistance. If this enzyme is used for inserting a gene for β -galactoside production and the recombinant plasmid is inserted in an E.coli strain
(a) It will be able to produce a novel protein with dual ability
(b) It will not be able to confer ampicillin resistance to the host cell
(c) The transformed cells will have the ability to resist ampicillin as well as produce β -galactoside
(d) It will lead to lysis of host cell
75. A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is:
(1) Poly(A) tail sequences
(2) Degenerate primer sequence
(3) Okazaki sequences
(4) Palindromic Nucleotide sequences
76. During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first?
(1) Ligation
(2) Annealing
(3) Extension
(4) Denaturation
77. The Adenosine deaminase deficiency results into
(1) Addison’s disease
(2) Dysfunction of Immune system
(3) Parkinson’s disease
(4) Digestive disorder
Solutions :
1.Solution: (d)
Plants developed by genetic engineering are called transgenic plants or genetically modified crops from which genetically modified food is produced. For their production micro-organisms (bacteria, virus) are used. So, by consuming them there is a danger of entry of viruses and toxins causing differ types of allergies and other health hazards to human beings.
2.Solution: (b)
Gel electrophoresis is a technique to separation of DNA fragments according to their size. DNA is negatively charged so in gel tank when electric passed, DNA move towards positive electrode.
3.Solution: (a)
The linking of antibiotic resistance gene with the plasmid vector became possible with DNA ligase. DNA ligase is an enzyme that is able to join together two portions of DNA and therefore plays an important role in DNA repair. DNA ligase is also used in recombinant DNA technology as it ensures that the foreign DNA is bound to the plasmid into which it is incorporated.
4.Solution: (d)
Direct gene transfer is the transfer of naked. DNA into plant cells but the presence of rigid plant cell wall acts as a barrier to uptake. Therefore protoplasts are the favoured target for direct gene transfer. Polyethylene glycol mediated DNA uptake is a direct gene transfer method that utilizes
the interaction between polyethylene glycol, naked DNA, salts and the protoplast membrane to effect transport of the DNA into the cytoplasm. Solutions
5.Solution: (d)
Activated sludge is a process for treating sewage and industrial wastewaters using air and a biological floc composed of bacteria and protozoans. During the process, the primary effluent is taken to aeration tank that contain large number of aerobic heterotrophic microbes. They form flocs that digest a lot of organic matter. As the biological oxygen demand of waste water is reduced, it is passed into settling tank to undergo sedimentation. The sediment of the settling tank is called activated sludge that is a rich source of aerobic bacteria.
Hence, the statement (d) is correct. Biogas is produced by anaerobic breakdown of biomass with the help of methanogenic bacteria. It is made up of methane, carbon dioxide with traces of nitrogen, hydrogen sulphide and hydrogen. Methanobacterium is an anaerobic bacterium that is found in rumen of cattle and is helpful in the breakdown of cellulose.
6.Solution: (d)
Retrovirus as has the ability to transform normal cells into cancerous cells. Hence, it can used as a vector for cloning desirable genes into animal cells.
7.Solution: (c)
Palindromic sequences in DNA molecule are group of bases that forms the same sequence when read in both forward and backward direction. In the given question, only option (c) represent a palindromic sequence.
8.Solution: (b)
DNA or RNA segment tagged with a radioactive molecule is called Probe. They are used to detect the presence of complementary sequences in nucleic acid samples. Probes are used for identification and isolation of DNA and RNA.
9.Solution: (a)
Restriction endonucleases are enzymes that makes cuts at specific positions within the DNA molecule. They acts as molecular scissors. They recognise specific base sequence at palindrome sites in DNA duplex and cut its strands.
10.Solution: (d)
EcoRI is an endonuclease enzyme isolated from strains of E.coli and a part of restriction modified system. So co part stands for coli.
11.Solution: (d)
In gel electrophoresis agarose extracted from sea weed used as gel garose, made of 0.7% gel show good resolution of large DNA and 2% gel will show good resolution of small fragments.
12.Solution: (a)
Bacillus thuringiensis produces a large amount of crystalline protein during sporulation. In the cell toxins are formed along with the spore and are referred to as parasporal body. The bacteria are capable of entering the insect‘s blood and using the host insect to reproduce. The proteins from
ingested spores are activated by gut, high pH and the polypeptide toxins destroy gut epithelial cells and kill the pest.
14. Solution: (d)
15.Solution: (d)
A single strand Dna or rna tagged with radioactive molecule that is used in of hybridization of DNA or RNA is called probe.
16.Solution: (d)
The name of this DNA polymerase is Taq polymerase extracted from a thermophilic bacterial.
17.Solution: (d)
For gene transfer into the host cell without using vector microparticles made of tungsten and Gold coated with foregin DNA are bombarded into target cells at a very high velocity.
18.Solution: (d)
Biolistic it is direct gene transferred method for constructing recombinant DNA. The gene gun was invented by John C. Sanford with Edward Wolf. A gene gun can be used to genetically infect cells or whole organisms with foreign DNA by aiming the barrel of the gun and firing. The microshot
projectiles in the biolistic gene gun are made of microscopic (or nano) sized gold or platinum powders. These expensive powders are soaked in DNA or RNA (in raw or plasmid form) that are engineered for insertion into the genome of the cells or organisms under the gun.
19.Solution: (a)
Antibiotics are powerful medicines that fight bacterial infections. They either kill bacteria or keep them from reproducing. In genetic engineering, the antibiotics are used as selectable markers.
20.Solution: (c)
PCR is a technique for enzymatically replicating DNA without using a living organism such as E. coli or yeast. It is commonly used in medical and biological research labs for a variety of tasks like detection of hereditary diseases, identification of genetic fingerprints etc. The correct steps shown in the above figure are: A – Denaturation at a temperature of about 94° to 98°C. During the denaturation, the double strand melts open to single stranded DNA, and all enzymatic reactions stop. B – Annealing (binding of DNA primer to the separated strands. Occurs at 50° to 5°Celsius, which is lower than the optimal temperature of the DNA polymerases) C – Extension or elongation of the strands using the DNA primer with
heat-stable DNA polymerases, most frequently Taq (Thermusaquaticus) at 72ºC.
21.Solution: (a)
A palindromic sequence is a nucleic acid sequence (DNA or RNA) that is the same whether read 5′ (five-prime) to 3′ (three prime) on one strand or 5′ to 3′ on the complementary strand with which it forms a double helix.
22.Solution: (b)
DNA fragments generated by restriction endonucleases in a chemical reaction can be separated by gel electrophoresis. Since DNA fragments are negatively charged molecules they can be separated by forcing them to move towards the anode under an electric field through a medium/matrix.
The DNA fragments separate according to their size through sieving effect provided by matrix.
23. Solution: (d)
Alternative selectable markers have been developed which differentiate recombinant from non-recombinants on the basis of their ability to produce colour in the presence of chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme β-
galactosidase. This results into inactivation of the enzyme, which is referred to as insertional inactivation. The presence of chromogenic substrate give blue coloured colonies of the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the
galactosidase and the colonies do not produce any colour, these are identified as recombinant colonies.
24.Solution: (c)
A hybridization probe is a fragment of DNA of variable length which is used in DNA samples to detect the presence of nucleotide sequence (the DNA target) that are complementary to the sequence in the probe. The probe hybridize to single– stranded DNA whose base sequence allow
probe target base-pairing due to complementary between the probe and target.
25.(c) They can cut DNA at specific base sequences
26.(b) selectable marker. A selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture, that confers a trait suitable for artificial selection.
27.(c) introduction of gene for adenosine deaminase in persons suffering from Severe Combined Immuno Deficiency (SCID).
28.(c) Chemical – mediated genetransfer
29.(c) Biosynthetic stage for synthesis of product in recombinant DNA technology is called upstreaming process while after completion of biosynthetic stage, the product has to be subjected through a series of processes which include separation and purification are collectively referred to as downstreaming processing.
30.(c) The PCR technique as we know today was conceptualized and developed in the 1980s by Kary Mullis and his colleagues at Cetus Corporation
31.(d) Expression of recombinant DNA is part of upstream processing.
32.(a) restriction enzymes (or restriction endonucleases) are used to cut DNA into smaller fragments. The cuts are always made at specific nucleotide sequences
33.(a) Taq polymerase, generally used in PCR is isolated from thermophilic bacterium Thermus aquaticus.
34.(c) We can cut DNA at specific sites by endonucleases like DNAs
35.(b) Zinc finger proteins are among the most abundant proteins in eukaryotic genomes. Their functions are extraordinarily diverse and include DNA recognition, RNA packaging, transcriptional activation, regulation of apoptosis, protein folding and assembly, and lipid binding.
36.(d) PCR
37.(b) The most important rool in genetic engineering of plants has been the Ti plasmid of soil bacterium, Agrobacterium tumefaciens. E. coli has also been extensively used for genetic engineering in animals, like in production of humulin, somatotropin, etc.
38.(d) Probes are single stranded, radiolabelled molecules of nucleic acids with known sequence. The probes having sequence complementary to the gene to be identified are supplied. They bind with the particular gene segment. Radiation imaging identifies the location of that particular segment which bind with probe. Probes are used as identification tool.
39.(b) A palindromic sequence is a sequence made up of nucleic acids within double helix of DNA and/or RNA that is the same when read from 5′ to 3′ on one strand and 5′ to 3′ on the other, complementary, strand. It is also known as a palindrome or an inverted-reverse sequence
40.(c) Ethanol is much less polar than water. Adding it to the solution disrupts the screening charges exerted by water. The electrical attraction between phosphate and any positive ions (Na+)present in solution becomes strong enough to form a stable ionic bond and DNA precipitates. Ethanol precipitation is a widely used technique to purify, or concentrate nucleic acid.
41.(c) genetic transformation
42.(c) Biolistics is a method for the delivery of nucleic acid to cells by high-speed particle bombardment. The technique uses nucleic acid-coated particles propelled by a pressurized gun (gene gun) to transfect cells or organelles
43.(d) coli
44.(b) Plasmid is a small circular double stranded DNA molecule present in the cytoplasm of the bacterial cell. It can replicate independently of bacterial chromosome. Due to this characteristic of plasmid, it is used as the vector (vectors are for the transferring of a piece of DNA to target gene) in gene cloning.
45 (c)Agarose gel electrophoresis is used to segregate DNA fragments according to the mass and size. Ethidium bromide is the fluorescent stain used in this technique. Ethidium bromide, when exposed to ultraviolet light, produces a fluorescent effect. Hence the DNA tagged by it can be traced quickly on the transparent gel.
46 (a)Downstream processing (DSP) describes the series of operations required to take biological materials, such as cells, tissue culture fluid, or plant tissues, and derive from them a pure and homogeneous protein product.
47 (a)DNA fragmentation is the separation or breaking of DNA strands into pieces. It can be done intentionally by laboratory personnel or by cells, or can occur spontaneously. Spontaneous or accidental DNA fragmentation is fragmentation that gradually accumulates in a cell. DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C). The order of these bases is what determines DNA’s instructions, or genetic code. Sperm DNA fragmentation can be caused by intrinsic factors like abortive apoptosis, deficiencies in recombination, protamine imbalances or oxidative stress.
DNA fragments are negatively charged, so they move towards the positive electrode.
48. (d)A selectable marker is a gene introduced into a cell, especially a bacterium or to cells in culture, that confers a trait suitable for artificial selection. A selectable marker controls a gene that encodes a protein, which allows transformed plants to survive in toxic environments, while nontransformed cells and tissues die.
49. (a)Gel electrophoresis is used to segregate DNA fragments according to the mass and size. DNA is negatively charged and it will travel towards the positive electrode. Hence separation will be on the size of the fragments. The smaller DNA molecules move faster and farthest followed by the larger ones
50 (a)A retrovirus is a type of virus that inserts a copy of its RNA genome into the DNA of a host cell that it invades, thus changing the genome of that cell.
51 (b) Bioprospecting is the exploration of natural sources for small molecules, macromolecules and biochemical and genetic information that could be developed into commercially valuable products for the agricultural, aquaculture, bioremediation, cosmetics, nanotechnology, or pharmaceutical industries. The term biopiracy was coined by Pat Mooney, to describe a practice in which indigenous knowledge of nature, originating with indigenous peoples, is used by others for profit, without authorization or compensation to the indigenous people themselves.
52 (c) Genetic Engineering Appraisal Committee (GEAC).
The Genetic Engineering Appraisal Committee (GEAC) is a statutory body constituted under the ‘Rules for the Manufacture, Use /Import /Export and Storage of Hazardous Microorganisms/Genetically Engineering Organisms or Cells, 1989.
53(c) This technique is used for making multiple copies of gene (or DNA) of interest in vitro. Each cycle has three steps
(1) Denaturation
(2) Primer annealing
(3) Extension of primer
54 (c) Basmati
55 (d) A bioreactor refers to any manufactured device or system that supports a biologically active environment. Used in industrial processes to produce pharmaceuticals, vaccines, or antibodies. Also used to convert raw materials into useful byproducts such as in the bioconversion of corn into ethanol
56 (b)During the isolation of desired gene, chilled ethanol is used for the precipitation of DNA.
57 (b) Restriction enzyme, also called restriction endonuclease, a protein produced by bacteria that cleaves DNA at specific sites along the molecule. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.
58 (a) It is Vitamin A enriched, with a gene from daffodil. Genetically engineered “Golden Rice” contains up to 35 μg β-carotene per gram of rice. It is important to determine the vitamin A equivalency of Golden Rice β-carotene to project the potential effect of this biofortified grain in rice-consuming populations that commonly exhibit low vitamin A status.
59(c) Bacillus thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxic insecticidal protein. These protein exist as inactive protoxins but once an insect ingest the inactive toxin, it is converted into an active form of toxin due to alkaline pH of the gut which solubilize the crystals. The activated toxin binds to the surface of midgut epithelial cells and create pores that cause cell swelling and lysis and eventually cause death of insect.
60(d) The sequence that controls the copy number of the linked DNA in the vector, is termed Ori site.
61 (a)The specific palindromic sequence which is recognized by EcoRI is
5′ – GAATTC – 3′
3′ – CTTAAG – 5
62 (a) Agarose gel electrophoresis is used to resolve DNA fragments on the basis of their molecular weight. Smaller fragments migrate faster than larger ones; the distance migrated on the gel varies inversely with the logarithm of the molecular weight. The size of fragments can therefore be determined by calibrating the gel, using known size standards, and comparing the distance the unknown fragment has migrated. This technique can be used to resolve complex DNAs (i.e., genomic DNA) for Southern blot analysis or to resolve simpler digests of bacteriophage and plasmid clones for RE site mapping and blotting.
63(c) Polymerases— Polymerization of nucleotides
Nucleases — Digestion of nucleic acid
Exonucleases— Remove nucleotides from the end of DNA
64(c) A superior ovary is an ovary attached to the receptacle above the attachment of other floral parts. A superior ovary is found in types of fleshy fruits such as true berries, drupes, etc. A flower with this arrangement is described as hypogynous. Examples of this ovary type include the legumes (beans and peas and their relatives).
Half-inferior ovary
A half-inferior ovary is embedded or surrounded by the receptacle.[19] This occurs in flowers of the family Lythraceae, which includes the crape myrtles. Such flowers are termed perigynous or half-epigynous. In some classifications, half-inferior ovaries are not recognized and are instead grouped with either the superior or inferior ovaries.
Inferior ovary
An inferior ovary lies below the attachment of other floral parts. A pome is a type of fleshy fruit that is often cited as an example, but close inspection of some pomes will show that it is really a half-inferior ovary. Flowers with inferior ovaries are termed epigynous.
65(b) Joining of sticky end is not the function of restriction enzymes.
66(c) • Bt cotton — Bacillus thuringiensis
• Adenosine deaminase deficiency—Gene therapy
• RNAi—Cellular defence
• PCR—Detection of HTV infection
67(a) The functional insulin has A and B chains linked together by disulfide bonds.
68 (c)Bt cotton variety that was developed by the introduction of toxin gene of Bacillus thuringiensis (Bt) is resistant to ) Insect pests.
Insect pests cause significant damage to agricultural products intended for human foods and animal feeds. to direct losses caused by insects to plant systems, fruits, and seeds, these biotic agents cause indirect losses because they leave important contaminants such as body parts or exoskeletons, insect eggs, and off-odors on produce.
69 (b) The first step in the polymerase chain reaction is denaturation during which strands of dsDNA separate. This requires temperature around 94°C. This is followed by annealing in which primers anneal to 3′ end of template DNA strand. Annealing is followed by extension in which Taq polymerase adds nucleotides to 3’OH end of primers. 70(c) Various enzymes like protease, RNase, etc. are added to break down substances like proteins, RNA, etc. Once all these substances are broken down, DNA is left which is precipitated out by adding chilled ethanol. Histones are basic proteins that help condense DNA in a cell.
71 (c) Gene therapy is a collection of methods that allows correction of a gene defect that has been diagnosed in a child/embryo. Here genes are inserted into a person’s cells and tissues to treat a disease. Amplification is sed to increase the expression of desired gene
72 (c) Protoplast fusion – Pomato
Plant tissue culture – Totipotency
Meristem culture – Virus free plants
Micropropagation – Somaclones
73 (d) PCR is Polymerase Chain Reaction. It is used for making multiple copies of the gene. Hence PCR is used for
• Gene amplification.
• PCR-based assays have been developed that detect the presence of gene sequences of the infectious agents.
• It is also used in detecting mutations.
• Protein is not the target of PCR. Hence, plays no role in its purification.
74 (b) Since the gene is inserted at Pst I of ampR region of pBR322, the ampR gene is inactivated which is called as insertional inactivation. Hence the genetically modified E.coli strain will not be able to confer ampicillin resistance.
75(d) Palindromic Nucleotide sequence is specific recognition sequence identified by endonucleases to cut the DNA strands at the specific positions.
76(d) Denaturation
77(b) Adenosine deaminase (ADA) is crucial for the immune system to function. Its deficiency causes severe combined immunodeficiency.
