MCQGeeks
0 : 0 : 1
CBSE
JEE
NTSE
NEET
English
UK Quiz
Quiz
Driving Test
Practice
Games
NEET
NEET Biology MCQ
Neet Biology Biotechnology Mcq
Quiz 8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Q.1
ion 80 Which one of the following bacteria has found extensive use in genetic engineering work in plants?
0%
a) Agrobacterium tumefaciens
0%
b) Clostridium septicum
0%
c) Xanthomonas citri
0%
d) Bacillus coagulans
Explanation
Using Agrobacterium vectors, nematode-specific genes were introduced into the host plant. Answer:(a)
Q.2
on 171 DNA can be introduced into any cell by
0%
a) Injection
0%
b) being complexed with Ca salts
0%
c) gel electrophoresis
0%
d) none of these
Explanation
Answer:(a)
Q.3
ion 45 Study the following sentences regarding recombinant DNA technology and select the incorrect ones: (i) Taq polymerase extends the primers using the nucleotides provided in the reaction. (ii) Antibiotic resistant genes are considered as desirable genes in recombinant DNA technology. (iii) DNA fragments are separated according to their charge only, in agarose gel electrophoresis. (iv) Transformation is a procedure through which a piece of DNA is introduced into a host bacterium. (v) To produce higher yields of a desired protein, host cell can be multiplied in a continuous culture. (vi) Downstream processing is one of the steps of polymerase chain reaction.
0%
a) (ii), (iii) and (vi)
0%
b) (i), (iii) and (v)
0%
c) (i) and (iii)
0%
d) (i) and (ii)
Explanation
Taq polymerase helps in amplification of DNA fragments in PCR technique. Enzyme taq polymerase extends the primers using the nucleotides provided in the reaction and the genomic DNA as template. (i) is correct. Transformation is a procedure through which a piece of DNA is introduced in a host bacterium. (iv) is correct. The cells can also be multiplied in a continuous culture system. This type of culturing method produces a larger biomass leading to higher yields of desired protein. (v) is correct. Antibiotic resistance genes are selectable markers. Desirable genes are the ones which are introduced in the vector for getting desired protein product. (ii) is incorrect. The DNA fragments separate (resolve) according to their size through sieving effect provided by the agarose gel. (iii) is incorrect. The processes of separation and purification are collectively referred to as downstream processing. (vi) is incorrect. Answer:(a)
Q.4
ion 46 A restriction endonuclease breaks bonds between the:
0%
a) Base pairs of a DNA molecule
0%
b) Base pairs of DNA – RNA hybrid molecule
0%
c) Sugar and phosphate components of a nucleic acid molecule
0%
d) Exons and introns of a DNA molecule
Explanation
Each restriction endonuclease functions by ‘inspecting’ the length of a DNA sequence. Once it finds its specific recognition sequence, it will bind to the DNA and cut each of the two strands of the double helix at specific points in their sugar -phosphate backbones. Answer:(c)
Q.5
ion 47 When typical restriction enzymes cut a DNA molecule, the cuts are uneven, so that the DNA fragments have single stranded ends. These ends are useful in recombinant DNA works because:
0%
a) They serves as starting points for DNA replication
0%
b) Only single stranded DNA segments can code for proteins
0%
c) They enable researchers to use the fragments as molecular probes
0%
d) The fragments will bond to other fragments with complementary ends
Explanation
Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources/genomes. Restriction enzymes cut the strand of DNA between the same two bases on the opposite strands. This leaves single stranded portions at the ends. There are overhanging stretches called sticky ends on each strand. These are named so because they form hydrogen bonds with their complementary cut counterparts. This stickiness of the ends facilitates the action of the enzyme DNA ligase. Answer:(d)
Q.6
ion 48 The alternative selectable markers have been developed which differentiates recombinants from non – recombinants on the basis of their ability to:
0%
a) Produce colour in the presence of chromogenic substrate
0%
b) Produce fluorescence
0%
c) Produce light
0%
d) All of the above
Explanation
selectable markers have been developed which differentiate recombinants from non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. Answer:(a)
Q.7
ion 49 The enzyme that cleaves DNA at specific sites, producing sticky ends is called
0%
a) Restriction endonuclease
0%
b) Cleaving enzyme
0%
c) Lysing enzyme
0%
d) Exonuclease
Explanation
Restriction endonuclease cut the strand of DNA a little away from the centre of the palindrome sites, but between the same two bases on the opposite strands. This leaves single stranded portions at the ends. There are overhanging stretches called sticky ends on each strand. These are named so because they form hydrogen bonds with their complementary cut counterparts. Answer:(a)
Q.8
ion 50 Retro viruses have genetic material which is
0%
a) DNA
0%
b) RNA
0%
c) both DNA & RNA
0%
d) proteins
Explanation
A retrovirus is a virus that uses RNA as its genomic material. Upon infection with a retrovirus, a cell converts the retroviral RNA into DNA, which in turn is inserted into the DNA of the host cell. Answer:(b)
Q.9
ion 51 There are special proteins that help to open up DNA double helix in front of the replication work. These proteins are........
0%
a) DNA gyrase
0%
b) DNA polymerase I
0%
c) DNA ligase
0%
d) DNA topoisomerase
Explanation
DNA gyrase, or simply gyrase, is an enzyme within the class of topoisomerase Gyrase belongs to a class of enzymes known as topoisomerases that are involved in the control of topological transitions of DNA. topological properties of the genetic material, including DNA underwinding and overwinding, knotting, and tangling, profoundly influence virtually every major nucleic acid process Answer:(a)
Q.10
ion 52 A sequence of in a genome at which replication is initiated in .........
0%
a) origin of replication
0%
b) selectable marker
0%
c) cloning site
0%
d) origin of restriction
Explanation
The origin of replication (also called the replication origin) is a particular sequence in a genome at which replication is initiated Answer:(a)
Q.11
ion 53 The genetic recombinants obtained by insertion of plasmid into 1 phage genome is called
0%
a) Cosmid
0%
b) plasmid
0%
c) Phasmids
0%
d) foreign DNA
Explanation
Cosmid vectors are designed to clone large fragments of DNA and to grow their DNA as a virus or as a plasmid. Answer:(a)
Q.12
ion 54 Assertion - Hybridoma cells are shifted to a medium deficient in nutrient which cannot be synthesized by myeloma cells Reason - This medium allows selection of hybridoma cells
0%
a) Assertion is correct, Reason is explanation of Assertion
0%
b) Assertion is correct, Reason is correct but it is not explanation of Assertion
0%
c) Assertion is correct, Reason is false
0%
d) Assertion is wrong, Reason correct
Explanation
Hybridoma is a culture of hybrid cells that results from the fusion of B cells and myeloma cells. Fused cells are incubated in HAT medium (hypoxanthine-aminopterin-thymidine medium) for roughly 10 to 14 days. Aminopterin blocks the pathway that allows for nucleotide synthesis. Hence, unfused myeloma cells die. In this way, only the B cell-myeloma hybrids survive, since the HGPRT gene coming from the B cells is functional. These cells produce antibodies (a property of B cells) and are immortal (a property of myeloma cells). Answer:(a)
Q.13
ion 55 Gel electrophoresis is used for
0%
a) Isolation of DNA molecule
0%
b) Cutting of DNA in to fragments
0%
c) Separation of DNA fragments according to their size
0%
d) Construction of recombinant DNA by joining with cloning Vector
Explanation
The cutting of DNA by restriction endonucleases results in the fragments of DNA. These fragments can be separated by a technique known as gel electrophoresis. Answer:(c)
Q.14
ion 56 Molecular scissors, which cut DNA at specific site
0%
a) ligase
0%
b) cellulase
0%
c) restriction endonuclease
0%
d) Polymerase
Explanation
Restriction endonucleases make cuts at specific positions within the DNA. Answer:(c)
Q.15
ion 57 First hormone prepared by genetic engineering is ....
0%
a) Insulin
0%
b) Oxytocin
0%
c) Adrenaline
0%
d) Somatotropin
Explanation
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. Chains A and B were produced separately, extracted and combined by creating disulfide bonds to form human insulin. Answer:(a)
Q.16
ion 58 The Prerequisites for biotechnological production of antibiotic is
0%
a) to search an antibiotic producing microorganism
0%
b) to isolate the antibiotic gene
0%
c) to join antibiotic gene with E coli plasmid
0%
d) All of the above
Explanation
Antibiotics can be produced biotechnologically by identifying and culturing the antibiotic-producing microorganism. The antibiotic gene is isolated and then linked with plasmid vector. The ability to multiply copies of antibiotic resistance gene in E. coli was called cloning of antibiotic resistance gene in E. coli. Answer:(d)
Q.17
ion 59 Classical biotechnology does not involve the production of:
0%
a) Curd
0%
b) Ethyl alcohol
0%
c) Insulin from E.coli
0%
d) Citric acid
Explanation
The second phase of evolution and development of biotechnology can be called 'Classical Biotechnology'. This phase existed from 1800 to almost the middle of the twentieth century. Early examples of biotechnology include breeding animals and crops, and using microorganisms to make cheese, yoghurt, bread, beer and wine. Answer:(c)
Q.18
ion 60 When the number of genes increases in response to some signal the effect is called as:
0%
a) Gene dosage
0%
b) Gene pool
0%
c) Gene amplification
0%
d) Gene frequency
Explanation
Gene amplification refers to a number of natural and artificial processes by which the number of copies of a gene is increased. Answer:(c)
Q.19
ion 63 Identify the correct order of steps involved in southern blotting hybridization using radiolabeled VNTR as a probe: I. Hybridization using labelled VNTR probe. II. Detection of hybridized DNA fragments by autoradiography. III. Isolation of DNA. IV. Separation of DNA fragments by electrophoresis. V. Digestion of DNA by restriction endonuclease. VI. Transfer of separated DNA fragments to synthetic membranes.
0%
a) III → V → IV → VI → I → II
0%
b) III → IV → V → I → VI → II
0%
c) II → III → IV → V → VI → I
0%
d) II → I → III → IV → V → VI
Explanation
The technique involved Southern blot hybridisation using radiolabelled VNTR as a probe. It included: (i) isolation of DNA (ii) digestion of DNA by restriction endonucleases, (iii) separation of DNA fragments by electrophoresis, (iv) transferring (blotting) of separated DNA fragments to synthetic membranes, such as nitrocellulose or nylon (v) hybridisation using labelled VNTR probe, and (vi) detection of hybridised DNA fragments by autoradiography. A schematic representation of DNA fingerprinting. Answer:(a)
Q.20
hy is it beneficial to have a multiple cloning site (MCS) within the lac Z gene?
0%
a) When foreign DNA interrupts the lac Z gene, no β galactosidase can be formed, and X Gal remains colourless. This allows the researcher to distinguish between recombinants and non – recombinant vectors
0%
b) The lac Z gene is robust; it can be cut and still remains its function of hydrolyzing lactose or X Gal
0%
c) The lac Z gene naturally has a lot of restriction sites within it, making it easy for cutting and pasting a foreign DNA
0%
d) Only plasmids have the lac Z gene, so it makes obtaining the vector much easier for genetic manipulation
Explanation
The z gene codes for beta-galactosidase (β-gal), which is primarily responsible for the hydrolysis of the disaccharide, lactose into its monomeric units, galactose and glucose. Multiple cloning sites are a feature that allows for the insertion of foreign DNA without disrupting the rest of the plasmid which makes it extremely useful in biotechnology, bioengineering, and molecular genetics. Answer:(a)
Q.21
ion 65 Which of the following is incorrect regarding Human Genome Project?
0%
a) The size of genome or number of genes is unconnected with the complexity of body organization
0%
b) Eukaryotes contain mostly coding areas or exons
0%
c) Microsatellites are 11 – 60 base pairs
0%
d) The longest gene of human body is that of muscular dystrophy in Y chromosome
Explanation
genome size is clearly not an indicator of the genomic or biological complexity of an organism. A microsatellite is a tract of repetitive DNA in which certain DNA motifs (ranging in length from one to six or more base pairs) are repeated, typically 5–50 times. The largest known gene is the human dystrophin gene, which has 79 exons spanning at least 2,300 kilobases. the structural gene in a transcription unit could be said as monocistronic (mostly in eukaryotes) or polycistronic (mostly in bacteria or prokaryotes). In eukaryotes, the monocistronic structural genes have interrupted coding sequences – the genes in eukaryotes are split. The coding sequences or expressed sequences are defined as exons Answer:(a)
Q.22
ion 66 pBR 322, which is frequently used as a vector for cloning gene in E.coli is:
0%
a) Original bacterial plasmid
0%
b) Modified bacterial plasmid
0%
c) Viral genome
0%
d) Transposon
Explanation
pBR322 is a plasmid and was one of the first widely used E. coli cloning vectors. Created in 1977 in the laboratory of Herbert Boyer at the University of California, San Francisco. Answer:(b)
Q.23
ion 67 Which of the following statements is not correct?
0%
a) Recombinant technologies are used to produce desirable proteins
0%
b) Agrobacterium is a genus of bacteria that causes tumours in plants
0%
c) Log phase does not show any significant increase in the number of cells whereas the lag phase shows rapid multiplication of cells
0%
d) First gene therapy was done to cure ADA deficiency
Explanation
The initial phase is the lag phase where bacteria are metabolically active but not dividing. The exponential or log phase is a time of exponential growth. Answer:(c)
Q.24
ion 68 A eukaryotic gene has "sticky ends" produced by the restriction endonuclease EcoRI. The gene is added to a mixture containing EcoRI and a bacterial plasmid that carries two genes conferring resistance to Ampicillin and tetracycline. The plasmid has one recognition site for EcoRI located in the tetracycline resistance gene. This mixture is incubated for several hours, exposed to DNA ligase, and then added to bacteria growing in nutrient broth. The bacteria are allowed to grow overnight and are streaked on a plate using a technique that produces isolated colonies that are clones of the original. Samples of these colonies are then grown in four different media: nutrient broth plus ampicillin, nutrient broth plus tetracycline, nutrient broth plus Ampicillin and tetracycline, and nutrient broth without antibiotics. Bacteria that contain the plasmid, but not the eukaryotic gene, would grow
0%
a) in the nutrient broth plus ampicillin, but not in the broth containing tetracycline
0%
b) in the nutrient broth without antibiotics only
0%
c) in the broth containing tetracycline, but not in the broth containing ampicillin
0%
d) in all three types of broth
Explanation
Answer:(d)
Q.25
ion 69 Having become an expert on gel electrophoresis, you are asked to examine a gel for a colleague. Where would you find the smallest segments of DNA?
0%
a) Near the positive electrode, farthest away from the wells
0%
b) Near the negative electrode, farthest away from the wells
0%
c) Near the positive electrode, nearer to the wells
0%
d) Near the middle, they tend to slow down after the first few minutes
Explanation
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 (resolve) according to their size through sieving effect provided by the agarose gel. Hence, the smaller the fragment size, the farther it moves from wells Answer:(a)
Q.26
ion 70 EFB stands for:
0%
a) European federation of biology
0%
b) European federation of biotechnology
0%
c) Eastern federation of biology
0%
d) Eastern federation of biotechnology
Explanation
The European Federation of Biotechnology (EFB) was established by European scientists in 1978. Answer:(b)
Q.27
ion 71 Total number of genes in Y chromosome:
0%
a) 221
0%
b) 231
0%
c) 251
0%
d) 237
Explanation
Chromosome 1 has most genes (2968), and the Y has the fewest (231). Answer:(b)
Q.28
ion 72 Restriction endonuclease is also known as -
0%
a) Molecular glue
0%
b) DNA ligase
0%
c) DNA Polymerase
0%
d) molecular scissors
Explanation
The cutting of DNA at specific locations became possible with the discovery of the so-called ‘molecular scissors’– restriction endonuclease. Answer:(d)
Q.29
ion 73 Which of the following are the essential requirements for recombination?
0%
a) Single stranded DNA
0%
b) DNA ligase
0%
c) DNA Polymerase I
0%
d) All of the above
Explanation
Restriction endonuclease and DNA ligase are essential for recombination. Answer:(b)
Q.30
ion 74 Which one of the following pairs is correctly matched?
0%
a) RNA polymerase - RNA primer
0%
b) Restriction enzymes - Genetic engineering
0%
c) Central dogma - codon
0%
d) okazaki fragments - splicing
Explanation
Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources/genomes. Answer:(b)
Q.31
ion 75 Which of the following step is necessary part of DNA recombination technology?
0%
a) Insertion of DNA fragment into vector
0%
b) Insertion of vector into Bacteria
0%
c) Multiplication of the clones containing the recombination molecule
0%
d) All the above
Explanation
When you insert a piece of alien DNA into a cloning vector and transfer it into a bacterial, plant or animal cell, the alien DNA gets multiplied. In almost all recombinant technologies, the ultimate aim is to produce a desirable protein. Hence, there is a need for the recombinant DNA to be expressed. If any protein encoding gene is expressed in a heterologous host, it is called a recombinant protein. Answer:(c)
Q.32
ion 76 Which of the following statement is incorrect?
0%
a) Cosmid contains gene coding for viral protein
0%
b) Cosmid replicates like plasmids
0%
c) Cosmid has antibiotic resistant marker gene
0%
d) Cosmid has 12 bases helping to join complete genome to make it circular
Explanation
Cosmid vectors are hybrids between plasmid and phage λ vectors. The classic example of cosmid vector is c2RB, which carries an origin of replication and a cloning site and has antibiotic-resistant genes. As with the phage λ vector, the cosmid vector encodes the cos sequences required for packaging of DNA into λ capsid. Cosmids can contain 37 to 52 (normally 45) kb of DNA. Cos sequences are ~200 base pairs long and essential for packaging. They contain a cosN site where DNA is nicked at each strand, 12 bp apart, by terminase. This causes linearization of the circular cosmid with two "cohesive" or "sticky ends" of 12bp Answer:(a)
Q.33
ion 77 Plasmid vectors can replicate only in bacteria such as E coli. Many of the vectors for use in eukaryotic cells are constructed such that they can exist both in eukaryotic cells and E coli. Such vectors are called:
0%
a) BAC’s
0%
b) YAC’s
0%
c) Cosmids
0%
d) Shuttle vectors
Explanation
A shuttle vector is a vector (usually a plasmid) constructed so that it can propagate in two different host species. Shuttle vectors include plasmids that can propagate in eukaryotes and prokaryotes. Answer:(d)
Q.34
ion 78 Assertion - The term hybridoma is applied to fused cells Reason - They are formed by the fusion of lymphocyte cell and myeloma cell
0%
a) Assertion is correct, Reason is explanation of Assertion
0%
b) Assertion is correct, Reason is correct but it is not explanation of Assertion
0%
c) Assertion is correct, Reason is false
0%
d) Assertion is wrong, Reason correct
Explanation
Hybridoma is a culture of hybrid cells that results from the fusion of B cells and myeloma cells. Assertion is true but reason is false. Answer:(c)
Q.35
ion 96 Which process is involved in making bread cheese, beer and wine ?
0%
a) Respiration / hydrolysis
0%
b) Degradation
0%
c) Fermentation
0%
d) Decomposition
Explanation
Fermentation is a chemical process by which carbohydrates, such as starch and glucose, are broken down anaerobically. Fermentation has many health benefits and is used in the production of alcoholic beverages, bread, cheese. Answer:(c)
Q.36
ion 81 Agarose extracted from weeds finds use in ______
0%
a) Spectrophotometry
0%
b) Tissue culture
0%
c) Gel electrophoresis
0%
d) PCR
Explanation
Gel electrophoresis is a technique to separate fragments of DNA. 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. Now-a-days the most commonly used matrix is agarose which is a natural polymer extracted from seaweeds (e.g., Gelidium, Gracilaria, Gigartina, etc.). Answer:(c)
Q.37
ion 82 Some of the steps involved in the production of insulin are given below. Choose the correct sequence (i) Synthesis of gene (DNA) for human insulin artificially (ii) Culturing recombinant E.coli in bioreactors (iii) Purification of insulin (iv) Insertion of human insulin gene into plasmid (v) Introduction of recombinant Plasmid into E.coli (vi) Extraction of recombinant gene product From E.coli
0%
a) (ii), (i), (iv), (iii) (v), (vi)
0%
b) (i), (iii), (v), (vi), (ii), (iv)
0%
c) (i), (iv), (v), (ii), (vi), (iii)
0%
d) (iii), (v), (ii), (i), (vi), (iv)
Explanation
Steps involved are as followed: 1. Synthesis of the gene for human insulin artificially. 2. Insertion of human insulin into plasmid. 3. Introduction of recombinant plasmid into E.coli. 4. Culturing recombinant E.coli in bioreactors. 5. Extraction of a recombinant gene product from E. coli 6. Purification of Humulin. Answer:(c)
Q.38
ion 83 An important limitation to the use of Agrobacterium tumefaciens is that:
0%
a) Infect dicots
0%
b) Be genetically modified
0%
c) Be cultured in nutrient medium
0%
d) Infect crop plants such as wheat, corn, etc
Explanation
Ti plasmid is a genetically engineered plasmid which has the ability of inducing cell division or tumour formation in plants. The Ti plasmid is formed by modifying the plasmid of Agrobacterium tumefaciens through genetic engineering. The limitation of this Ti-plasmid mediated gene transfer is that it can't be used to transform monocots such as grasses, corn. Answer:(d)
Q.39
ion 84 Structure involved in genetic engineering is:
0%
a) Plastid
0%
b) Restriction endonuclease
0%
c) DNA polymerase I
0%
d) Prochromosome
Explanation
Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources/genomes. Answer:(b)
Q.40
ion 85 In genetic engineering, a chimera is
0%
a) an enzyme that links DNA molecules
0%
b) a plasmid that contains foreign DNA
0%
c) a virus that infects bacteria
0%
d) a fungi
Explanation
Chimera, in genetics, an organism or tissue that contains at least two different sets of DNA, most often originating from the fusion of as many different zygotes (fertilized eggs). As per options, it can be a plasmid containing foreign DNA of two species. Answer:(b)
Q.41
ion 86 Which of the following vector can maintain the largest fragment of foreign DNA?
0%
a) YAC
0%
b) Cosmid
0%
c) Plasmid
0%
d) Phage
Explanation
Yeast artificial chromosome (YAC) is one engineered vector used to clone DNA sequences in yeast cells. Segments of an organism's DNA, up to one million base pairs in length, can be inserted into YACs. Yeast artificial chromosomes (YACs) are shuttle-vectors that can be amplified in bacteria and employed for the cloning and manipulation of large deoxyribonucleic acid (DNA) inserts (up to 3 Mb pairs) in the yeast Saccharomyces cerevisiae. Answer:(a)
Q.42
ion 87 Select the incorrect match:
0%
a) Agrobacterium tumefaciens – pathogen of monocot plants
0%
b) Retroviruses – pathogen of animal cells
0%
c) Chitinase – fungal cell wall degradation
0%
d) Chilled ethanol – precipitation of DNA
Explanation
The soil-dwelling bacterium Agrobacterium tumefaciens causes crown gall disease of dicots, which is a type of plant tumor. It does so by inserting a piece of a large plasmid it carries into susceptible plant cells. The plasmid is known as the Ti plasmid and the inserted DNA is called T-DNA Answer:(a)
Q.43
ion 88 Which of the following is an application of DNA fingerprinting?
0%
a) Useful in guiding breeding programmes for endangered animals
0%
b) Provides information about human lineage and relationship with great apes
0%
c) Study the relationships amongst various groups of people for knowing historical migration
0%
d) All of the above
Explanation
DNA fingerprinting is a very quick way to compare the DNA sequences of any two individuals. DNA fingerprinting is the basis of paternity testing, in case of disputes. In addition to application in forensic science, it has much wider application, such as in determining population and genetic diversities. Answer:(d)
Q.44
ion 89 If a person obtains transformants by inserting a recombinant DNA within the coding sequence of enzyme β- galactosidase, he will separate out recombinants from non – recombinants by which of the following observations?
0%
a) Non – recombinant colonies do not produce any colour whereas recombinant colonies give blue coloured colonies
0%
b) Recombinant colonies do not produce any colour whereas non – recombinant colonies gives blue coloured colonies
0%
c) Recombinants and non – recombinants both produce blue coloured colonies
0%
d) No colonies are formed due to Insertional inactivation
Explanation
Selection of recombinants due to inactivation of antibiotics is a cumbersome procedure because it requires simultaneous plating on two plates having different antibiotics. Therefore, alternative selectable markers have been developed which differentiate recombinants from non-recombinants on the basis of their ability to produce colour in the presence of a chromogenic substrate. In this, a recombinant DNA is inserted within the coding sequence of an enzyme, β-galactosidase. This results into inactivation of the gene for synthesis of this enzyme, which is referred to as insertional inactivation. The presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert. Presence of insert results into insertional inactivation of the β-galactosidase gene and the colonies do not produce any colour, these are identified as recombinant colonies. Answer:(b)
Q.45
ion 90 Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to:
0%
a) insert the fragments cut with X directly into the plasmid without cutting the plasmid
0%
b) cut the plasmid with restriction enzyme X and insert the fragments cut with Y into the plasmid
0%
c) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme
0%
d) cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X
Explanation
Because the plasmid only has a site for enzyme Y to cut, it will need to be cut with enzyme Y in order to create an opening to insert the gene. cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid Answer:(c)
Q.46
ion 91 In addition to Taq polymerase enzyme which other thermostable DNA polymerases have been isolated to be used in polymerase chain reaction (PCR)?
0%
a) Pfu polymerase isolated from Pyrococcus furiosus
0%
b) Tli polymerase (vent polymerase) isolated from Thermococcus litoralis
0%
c) Both (A) and (B)
0%
d) None of these
Explanation
Pfu polymerase and Tli polymerase have been isolated are also thermostable. Answer:(c)
Q.47
ion 92 Restriction endonucleases:
0%
a) Are present in mammalian cells for degradation of DNA when the cell dies
0%
b) Are used in genetic engineering for ligating two DNA molecules
0%
c) Are used for in vitro DNA synthesis
0%
d) Are synthesized by bacteria as part of their defense mechanism
Explanation
A bacterium uses a restriction enzyme to defend against bacterial viruses called bacteriophages, or phages. When a phage infects a bacterium, it inserts its DNA into the bacterial cell so that it might be replicated. The restriction enzyme prevents replication of the phage DNA by cutting it into many pieces. Answer:(d)
Q.48
ion 93 The genes encoding resistance to antibiotics such as ampicillin, Chloramphenicol, tetracycline or Kanamycin, etc. are considered as useful selectable markers for:
0%
a) Escherichia coli
0%
b) Bacillus thuringiensis
0%
c) Meloidogyne incognita
0%
d) Thermus aquaticus
Explanation
The genes encoding resistance to antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin, etc., are considered useful selectable markers for E. coli. The normal E. coli cells do not carry resistance against any of these antibiotics. Answer:(a)
Q.49
ion 94 A technique used to make numerous copies of a specific segment of DNA quickly and accurately
0%
a) Translation
0%
b) transcription
0%
c) Ligase chain reaction
0%
d) polymerase chain reaction
Explanation
Transcription makes mRNA from DNA but polymerase chain reaction make multiple copies of a segment of DNA Answer:(d)
Q.50
ion 95 Genetic engineering is possible because
0%
a) The phenomenon of transduction in bacteria is well understood
0%
b) We can see DNA by electron microscope
0%
c) We can cut DNA at specific sites by endonucleases like DNase I
0%
d) Restriction endonuclease purified from bacteria can be used in vitro
Explanation
Genetic engineering : Techniques to alter the chemistry of genetic material (DNA and RNA), to introduce these into host organisms and thus change the phenotype of the host organism. Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources/genomes. Each restriction endonuclease functions by ‘inspecting’ the length of a DNA sequence. Once it finds its specific recognition sequence, it will bind to the DNA and cut each of the two strands of the double helix at specific points in their sugar -phosphate backbones. Answer:(d)
0 h : 0 m : 1 s
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
Report Question
×
What's an issue?
Question is wrong
Answer is wrong
Other Reason
Want to elaborate a bit more? (optional)
Support mcqgeeks.com by disabling your adblocker.
×
Please disable the adBlock and continue.
Thank you.
Reload page