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CBSE Questions for Class 12 Medical Biology Biotechnology: Principles And Processes Quiz 9 - MCQExams.com
CBSE
Class 12 Medical Biology
Biotechnology: Principles And Processes
Quiz 9
Technique used to detect the DNA in a clone is
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0%
Polymerase chain reaction
0%
Gel electrophoresis
0%
Chromatography
0%
Autoradiography
Explanation
A single stranded DNA or RNA joined with a radioactive molecule (probe) is allowed to hybridise 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.
Bacteria genetically engineered to express a gene from a plant will
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Synthesise 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.
0%
Synthesis a protein with essentially the same sequence of amino acids as in the plant with differences relating to different colon wobble rules between prokaryotes and eukaryotes
0%
Not be able to synthesise a protein due to the presence of exon splicing sequences in the DNA sequence from the plant
0%
Not be able to synthesise a protein because transaction is coupled with transaction and posttranscriptional processing does not occur in it.
Explanation
When bacteria (a prokaryote) is engineered to express a gene from a plant (an eukaryote), a slightly different approach is used. Eukaryotic genes have both exons and Introns which are transcribed into the primary transcript. Primary transcript is then processed by splicing (removal of introns and joining of exons), capping and tailling to produce functional mRNAs. This functional mRNA is then expressed into proteins. Prokaryotes lack such machinery, hence expression of an eukaryotic DNA becomes difficult in prokaryotic cells. Therefore, scientists prepare cDNA from the functional nRNA (without introns) using reverse transcriptase. This DNA is incorporated into bacteria (or another prokaryotic cell) for expression of plant gene. Such foreign gene synthesises a protein with the same sequence of amino acids as in the plant, and therefore the proteins have the same structure and function as in the plant.
So, the correct answer is 'Synthesise 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.'
You discovered a novel eukaryotic organism that glows in the dark. You believe this trait is due to a single gene, and you wish to clone the gene. which of the following strategies is most likely to be successful?
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Isolate the genomic DNA from the organism, digest with a restriction endonuclease, insert into a plasmid vector and transform into a plasmid
0%
Isolate the genomic DNA from the organism, digest with a restriction endonuclease, insert into a plasmid vector and transform into bacteria. Screen colonies for for the ability to glow in the dark.
0%
Isolate mRNA from the organism, reverse transcribe and generate cDNA, insert into a plasmid vector and transform into bacteria. Screen colonies for the ability to glow in the dark.
0%
Isolate mRNA from the organism, reverse transcribe and genetate cDNA, Insert into a plasmid vector and transform into eukaryotic cells such as yeast. Screen colonies for the ability to glow in the dark.
Explanation
As it is a eukaryotic gene, it is better to be incorporated in a eukaryotic cell. Digestion by restriction endonuclease is not possible as the gene is unidentified and is to be isolated and cloned. It is better and easier to identify the gene transcript, i.e., protein coding mRNA, reverse transcribe it to produce cDNA and then transferring this intron less cDNA into an eukaryotic cell like yeast through a plasmid vector.
So, the correct answer is 'Isolate mRNA from the organism, reverse transcribe and generate cDNA, Insert into a plasmid vector and transform into eukaryotic cells such as yeast. Screen colonies for the ability to glow in the dark'.
Gel electrophoresis is a
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Technique of separation of charged molecules under the influence of magnetic field.
0%
Technique of incorporation of DNA molecules Into the cell through transient pore made due to electrical impulses.
0%
Technique of separation and isolation of DNA fragments through the pores of agarose.
0%
Technique of separation and purification of gene products.
Select the incorrect Statement regarding DNA replication with respect to the template strand
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Leading strand is formed in 5 $$\rightarrow$$ 3 direction.
0%
Okazaki fragments are formed in 5 $$\rightarrow$$ 3 direction.
0%
DNA polymerase catalyses polymerisation in 5 $$\rightarrow$$ 3 direction.
0%
DNA polymerase catalyses palymerisation in 3 $$\rightarrow$$ 5 direction.
Explanation
Since
DNA polymerase
requires a free
3
' OH group for initiation of synthesis, it can synthesize in only one
direction
by extending the
3
' end of the preexisting nucleotide chain. Hence,
DNA polymerase
moves along the template strand in a
3
'–
5
'
direction
, and the daughter strand is formed in a
5
'–
3
'
direction
.
So, the correct answer is '
DNA polymerase catalyses polymerisation in 5
→
→
3 direction'
Bacterial artificial chromosomes (BACs), cosmids, phages, plasmids and yeast artificial chromosomes (YACs) are all commonly used cloning vectors that differ in their cloning capacities, with a range from approximately 100 bp to 1000 kb. Which of the following is the increasing cloning capacity?
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BAC, cosmid, phage, plasmid, YAC
0%
YAC, BAC, cosmid, phage, plasmid
0%
Plasmid, phage, cosmid, BAC, YAC
0%
Plasmid, Cosmid, phage, BAC, YAC
Explanation
Plasmid - generally up to 15 Kb long DNA fragments
Phage - up to 23 Kb long DNA fragments
Cosmid - up to 45 Kb long DNA fragments
BAC - up to 300-350 Kb long DNA fragments
YAC - up to 1 Mb long DNA fragments
A doctor while operating on an HIV(+)ve patient accidentally cuts himself with a scalpel. Suspecting himself to have contracted the virus which test will he take to rule out/confirm his suspicion?
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0%
PCR
0%
Routine urine examination
0%
TLC
0%
DLC
Explanation
Very low count of bacteria or viruses (when the symptoms of the disease are not yet visible) can be detected by multiplication of their nucleic acid by PCR, (PCR can detect very low amounts of DNA). PCR is usually used to detect HIV in suspected AIDS patients.
The plasmid derived from
E.coli
is
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PBR $$327$$
0%
PBR $$322$$
0%
Phagemid
0%
None of the above
Explanation
A pBR 322 is a plasmid derived from
E. coli
. It is widely used
E. coli
cloning vectors. It contains the origin of replication and the rop gene, which encodes a restrictor of plasmid copy number. It also contains unique restriction sites for more than 40 restriction enzymes.
Thus, the correct answer is 'pBR 322.'
The term 'molecular scissors' generally refers to
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DNA polymerases
0%
RNA polymerases
0%
restriction endonucleases
0%
DNA ligases
Explanation
Restriction endonucleases cut DNA segments at specific sites of 4 or 6 base pair length, called the restriction sites and are therefore known as the molecular scissors. DNA polymerase helps in the synthesis of DNA and RNA polymerase catalyses the synthesis of RNA. DNA ligases on the other hand help in joining DNA fragments by helping in the formation of phosphodiester bonds between them. So, the correct option is 'restriction endonucleases'.
In the $$PCR$$ technology the $$DNA$$ segment is replicated over a billion times. This repeated replication is catalyzed by the enzyme.
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$$DNA$$ polymerase
0%
Taq polymerase
0%
$$DNA$$ dependent $$RNA$$ polymerase
0%
Primase
Explanation
Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.
T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, with a half-life of greater than 2 hours at 92.5 °C, 40 minutes at 95 °C and 9 minutes at 97.5 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.
So the correct option is 'Taq polymerase'.
The usual source of restriction endonucleases used in gene cloning is
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fungi
0%
bacteria
0%
plants
0%
viruses
Explanation
Bacterial species are the major source of commercial restriction enzymes. These enzymes serve to defend the bacterial cells from invasion by foreign DNA, such as nucleic acid sequences used by viruses to replicate themselves inside a host cell. Basically, the enzyme will chop DNA into much smaller pieces which pose little danger to the cell. The enzymes are named for the species and strain of bacteria that produces it. For instance, the first restriction enzyme extracted from Escherichia coli strain RY13 is called EcoRI, and the fifth enzyme extracted from the same species is called EcoRV.
So the correct option is 'Bacteria'.
In a genetic engineering experiment, restriciton enzymes can be used for
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0%
bacterial DNA only
0%
viral DNA only
0%
any DNA fragment
0%
eukaryotic DNA only
Explanation
Restriction enzymes, also called restriction endonucleases, bind to DNA and cleave the double strand, forming smaller pieces of DNA. There are three types of restriction enzymes; Type I restriction enzymes recognize a DNA sequence and cut the strand randomly more than one thousand base pairs away from the site. Type II restriction enzymes, the most useful for molecular biology laboratories, recognize and cut the DNA strand predictably at a specific sequence which is usually less than ten base pairs long. Type III restriction enzymes are similar to Type I, but these cut the DNA about thirty base pairs from the recognition sequence.
So the correct option is 'any DNA fragment'.
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?
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B - denaturation at a temperature of about $$98^0$$C separating the two DNA strands.
0%
A - denaturation at a temperature of about $$50^0$$C
0%
C - extension in the presence of heat stable DNA polymerase.
0%
A - annealing with two sets of primers.
Explanation
The key ingredients of a PCR reaction are Taq polymerase, primers, template DNA, and nucleotides (DNA building blocks). The ingredients are assembled in a tube, along with cofactors needed by the enzyme, and are put through repeated cycles of heating and cooling that allow DNA to be synthesized.
The basic steps are:-
Denaturation (96°C): Heat the reaction strongly to separate, or denature, the DNA strands. This provides single-stranded template for the next step.
Annealing (55 - 65°C): Cool the reaction so the primers can bind to their complementary sequences on the single-stranded template DNA.
Extension (72°C): Raise the reaction temperatures so Taq polymerase extends the primers, synthesizing new strands of DNA.
This cycle repeats 25- 35 times in a typical PCR reaction, which generally takes 22 - 44 hours, depending on the length of the DNA region being copied. If the reaction is efficient (works well), the target region can go from just one or a few copies to billions.
So the correct option is 'C - extension in the presence of heat stable DNA polymerase'.
The given figure is the diagrammatic representation of the $$E.coli$$ vector $$pBR \,322$$. Which one of the given options correctly identifies its certain components?
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$$ori - $$original restriction enzyme
0%
$$rop - $$reduced osmotic pressure
0%
$$Hin \,d \,III,\, Eco \,R\, I$$ - selectable markers
0%
$$amp^{R}, tet^{R}$$ - antibiotic resistance genes
Explanation
The plasmid is a naturally occurring, extrachromosomal, circular, double-stranded DNA that can replicate autonomously. It has been manipulated to act as vector for the biotechnological processes.
A.
ori
is the origin of replication region of the plasmid from where the replication can initiate.
B.
rop
region codes for a protein that maintains the copy number of plasmid in the cell.
C.
Hind III, EcoRI
are the sites on the plasmid that can be recognized by their respective restriction endonuclease and cut can be made so that gene-of-interest can be inserted.
D.
amp$$^{R}$$, tet$$^{R}$$
are the selectable markers or the antibiotic resistance genes that confer resistance against the ampicillin and the tetracycline and allow the selection of the transformed host cell in a culture.
So, the correct answer is '
amp$$^{R}$$, tet$$^{R}$$
- antibiotic resistance genes'
Which one is a true statement regarding $$DNA$$ polymerase used in $$PCR$$
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it is used to ligate introduced $$DNA$$ in recipient cell
0%
it serves as a selectable marker
0%
it is isolated from a virus
0%
it remains active at high temperature
Explanation
Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.
T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, with a half-life of greater than 2 hours at 92.5 °C, 40 minutes at 95 °C and 9 minutes at 97.5 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.
So the correct option is 'it remains active at high temperature'.
The taq polymerase enzyme is obtained from
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Thiobacillus ferroxidans
0%
Bacillus subtilis
0%
Pseudomonas putida
0%
Thermus aquaticus
Explanation
Taq polymerase is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction (PCR), a method for greatly amplifying the quantity of short segments of DNA.
T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein-denaturing conditions (high temperature) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq's optimum temperature for activity is 75–80 °C, with a half-life of greater than 2 hours at 92.5 °C, 40 minutes at 95 °C and 9 minutes at 97.5 °C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 °C.
So the correct option is '
Thermus aquaticus'.
$$Eco \,RI$$ cleaves the $$DNA$$ strands to produce
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blunt ends
0%
sticky ends
0%
satellite ends
0%
ori replication end
Explanation
EcoRI is a restriction endonuclease enzyme isolated from species E. coli. The Eco part of the enzyme's name originates from the species from which it was isolated, while the R represents the particular strain, in this case RY13. The last part of its name, the I, denotes that it was the first enzyme isolated from this strain. EcoRI is a restriction enzyme that cleaves DNA double helices into fragments at specific sites. It is also a part of the restriction modification system.
In molecular biology it is used as a restriction enzyme. EcoRI creates 4 nucleotide sticky ends with 5' end overhangs of AATT. The nucleic acid recognition sequence where the enzyme cuts is G/AATTC, which has a palindromic, complementary sequence of CTTAA/G. The / in the sequence indicates which phosphodiester bond the enzyme will break in the DNA molecule.
So the correct option is 'sticky ends'.
How many copies of the DNA sample are produced in PCR technique after 6-cycle?
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0%
$$4$$
0%
$$32$$
0%
$$64$$
0%
$$16$$
Explanation
Polymerase chain reaction (PCR) is a technique that exponentially amplifies a single copy of a specific DNA segment. It generates thousands of copies of that specific DNA segment. After completion of one cycle, 2 copies are produced from a single DNA segment. After completion of the second cycle,
2$$^2$$
= 4 copies are produced. Similarly, after n$$^{th}$$ cycle, 2$$^2$$ copies are produced, where n is the number of cycles. Hence, after completion of 6 cycle, 2$$^6$$ = 64 copies will be produced.
Thus, the correct answer is '64.'
Ideally, in a process of genetically modifying an organism, a vector should have
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Recognition site
0%
Tetracycline resistant site
0%
Kanamycin resistant site
0%
Chloramphenicol
resistant site
Explanation
A vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed. A vector should have a recognition site because without recognition site the required DNA can't be inserted into the vector for the transfer into another cell. When a vector has a recognition site it can be cut at those recognition sites with the help of enzymes and the required DNA fragment can be inserted into it for the transfer into another cell.
So, the correct answer is the 'Recognition site'.
The cutting of DNA at specific locations became possible with the discovery of
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0%
restriction enzymes
0%
probes
0%
selectable markers
0%
ligases
Explanation
A restriction enzyme or restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within the molecule known as restriction sites. Restrictions enzymes are one class of the broader endonuclease group of enzymes. Restriction enzymes are commonly classified into five types, which differ in their structure and whether they cut their DNA substrate at their recognition site, or if the recognition and cleavage sites are separate from one another. To cut DNA, all restriction enzymes make two incisions, once through each sugar-phosphate backbone (i.e. each strand) of the DNA double helix.
So the correct option is 'Restriction Enzymes'.
DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by
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electrophoresis
0%
restriction mapping
0%
centrigugation
0%
polymerase chain reaction
Explanation
Correct Answer: A
Explanation:
Treatment of DNA with
restriction endonuclease
produces a number of DNA fragments of variable lengths.
These fragments are separated through
gel electrophoresis
.
Gel electrophoresis is a technique of
separating biomolecules
under an
electric field
when placed over a matrix of
gel
.
In electrophoresis, the
cathode(-) and anode(+)
are present at the two ends of the instrument, and the matrix is made up of
agarose
.
The DNA fragments are placed over the cathode end. When an electric field is activated, the
negatively charged DNA
fragments
move
towards the
cathode
end.
The
sieve effect
of the agarose, causes the larger fragments to move slowly and smaller fragments to move fast.
Hence, the correct answer is
Electrophoresis
.
Commonly used vectors for human genome sequencing are ?
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0%
T-DNA
0%
BAC and YAC
0%
expression vectors
0%
T/A cloning vectors
Explanation
Correct Answer: B
Explanation:
During
human genome sequencing
, the DNA is isolated
for sequencing
, and broken into small fragments which are separated.
For the amplification of separated
fragments in the process, these are attached to the vectors like
BAC
(bacterial artificial chromosome and
YAC
(yeast artificial chromosome) and
cloned
inside the
host
bacteria or yeast.
Hence, the correct answer is
BAC and YAC
.
Which of the following restriction enzymes produces blunt ends?
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0%
Sal I
0%
Eco RV
0%
Xho
0%
Hind III
Explanation
A. Sal I is a restriction endonuclease isolated from
Streptomyces albus
. It produces sticky ends by making the cut in the nucleotide sequence
G/TCGAC
B. Eco RV is type II restriction endonuclease isolated from
Escherichia coli which
produces blunt ends by making a cut in the center of the nucleotide sequence GAT/ATC.
C. Xho is a restriction endonuclease isolated from
Xanthomonas campestris
. It produces sticky ends by making a cut in the recognition sequence
C/TCGAG.
D. Hind III is a type II restriction enzyme isolated from
Haemophilus influenzae
. It produces sticky ends by making a cut in the nucleotide sequence
A/AGCTT.
(Note: '/' denotes the position where the restriction enzyme is making cut in the nucleotide sequence).
So, the correct answer is 'Eco RV'.
Foreign DNA is also called
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0%
vehicle DNA
0%
Passenger DNA
0%
r-DNA
0%
Vector DNA
Explanation
For delivering the foreign DNA into the recipient cells we take the help of genetic vectors. They can replicate autonomously and typically include features to facilitate the manipulation of DNA. They are also referred to as the vehicle for foreign DNA.
So, the correct option is 'Vehicle DNA'.
In reference to DNA polymerase III, which statement is wrong?
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It requires ATP For polymerase action.
0%
Required for PCR
0%
More active than DNA Pol I & II
0%
Requires a previously made template to work on
Explanation
Like DNA replication in an organism, PCR requires a
DNA polymerase
enzyme that makes new strands of DNA, using existing strands as templates. The
DNA polymerase
typically used in PCR is called
Taq polymerase
, after the heat-tolerant bacterium from which it was isolated
(Thermus aquaticus).
So, the correct option is 'Required for PCR'.
Observe the diagram of pBR322 and select the INCORRECT statement.
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0%
They have antibiotics resistant gene for tetracycline and amipicillin.
0%
It has a Origin of replication.
0%
It has rop gene.
0%
None of the above
Explanation
pBR322 DNA is a commonly used plasmid cloning vector in E. coli. The molecule is a double-stranded circle 4,361 base pairs in length. pBR322 contains the genes for resistance to ampicillin and tetracycline and can be amplified with chloramphenicol. It contains the origin of replication(Ori) of pMB1, and the rop gene, which encodes a restrictor of plasmid copy number. The plasmid has unique restriction sites for more than forty restriction enzymes.
So, the correct answer is 'None of the above'.
Which of the following is not necessary to execute polymerase chain reaction successfully?
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All four DNA bases
0%
Short DNA base pairs
0%
DNA polymerase
0%
DNA library
Identify the INCORRECT statement.
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0%
The first restriction endonuclease enzyme, which has been isolated and characterized was Hind III.
0%
EcoRI recognize 5` GAATTC-3`, and cut the DNA between G and A
0%
The genes of plasmids encoding resistance to antibiotics like ampicillin, tetracycline, etc are considered useful selectable markers for Coli.
0%
pUC19 also encodes for an ampicillin resistance gene.
Explanation
a) The first restriction endonuclease enzyme, which has been isolated and characterized was Hind II. It was isolated from the bacterium
Haemophilus influenzae
by Hamilton Smith, Thomas Kelly and Kent Wilcox.
b) EcoRI restriction enzymes recognize hexamer 5'-GAATTC-3' and cute the DNA between G and A.
c) The genes of plasmids encoding resistance to antibiotics like ampicillin, tetracycline, etc are considered useful selectable markers for
E. coli.
If the plasmid is successfully inserted into the host genome, the antibiotic resistant gene will be encoded and the host will be able to grow in presence of specific antibiotic.
d) A plasmid called as pUC19 encodes for β-galactosidase. It also encodes for an ampicillin resistance gene.
Thus, the correct answer is 'The first restriction endonuclease enzyme, which has been isolated and characterized was Hind III.'
Which of the following is not a method of introducing alien DNA into host cells?
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Micro injection
0%
Electroporation
0%
Being placed along with the cell into a gene gun
0%
Gel electrophoresis
Explanation
A. Microinjection is a technique in which DNA is directly injected into the host cells with the help of microinjection.
B. Electroporation is a technique in which pores are created in the cell membrane and thus, permeability is increased. As a result, foreign DNA can easily enter the cells.
C. Gene gun is a method to introduce alien DNA into host cells through microprojectile particles. The DNA coated gold or tungsten particles are bombarded with the host cells and alien DNA enters the cells.
D. Gel electrophoresis is a technique of separating DNA fragments on the basis of their size.
Hence, option D is not a method of introducing alien DNA into host cells.
So, the correct answer 'Gel electrophoresis'.
A DNA sequencing reaction was performed with the fragment $$5-XXXGCGATCGYYYY-3'$$ as the template, dideoxy GTP, all the four $$dNTPs$$, and the required primers and enzyme. $$XXXX$$ and $$YYYY$$ in the given DNA fragment represent primer binding sites. The set of fragments obtained during the reaction will be (the primers are not shown in the amplified fragments).
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0%
$$5'-CGATCGC-3'$$ only
0%
$$5'-CG-3', 5'-CGCTAG-3', 5'-CCCTAGC-3'$$
0%
$$5'-CG-3', 5'-CGATCG-3', 5'-CGATCGC-3'$$
0%
$$5'-G-3', 5'-GCG-3', 5'-GCGATCG-3'$$
Explanation
A DNA sequencing reaction was performed with the fragment
5
−
X
X
X
G
C
G
A
T
C
G
Y
Y
Y
Y
−
3
′
as the template, dideoxy GTP, all the four
d
N
T
P
s
, and the required primers and enzyme.
X
X
X
X
and
Y
Y
Y
Y
in the given DNA fragment represent primer binding sites. The set of fragments obtained during the reaction will be CGATCGC, because if primer is attache to the XXXX binding site it polymerization starts and its complimentary fragment is CGATCGC.
Most important part if Ti-plasmid at which desired gene is put to target into plant cell is
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0%
Ti-gene
0%
Vir gene
0%
T- DNA
0%
Ori site
Explanation
Most important part if Ti-plasmid at which desired gene is put to target into the plant cell is Vir gene. The Ti-plasmid contains several genes containing Ti-gene, Vir gene etc. Ti gene is used to express specific compounds, which are used by the bacterium as a carbon source. The Vir gene is an important part of Ti-plasmid at which desired gene is put to target into a plant cell.
So, the correct answer is 'Vir gene'.
Polymerisation of DNA is in
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0%
$$3' \rightarrow 5'$$ direction
0%
$$5' \rightarrow 3'$$ direction
0%
Both $$3' \rightarrow 5'$$ and $$5' \rightarrow 3'$$ direction
0%
None of the above
Explanation
DNA polymerase has 5' $$\rightarrow$$ 3' activity. All known DNA replication systems require a free 3' hydroxyl group before synthesis can be initiated (note: the DNA temple is read in 3' to 5' direction whereas a new strand is synthesized in 5' to 3' direction).
So, the correct answer is "
5' $$\rightarrow$$ 3'
".
A bacterial plasmid ________
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0%
Does not replicate
0%
Can replicate independently
0%
Replicates, but with some association with chromosome
0%
Shows independent assortment (like in Mendelian Genetics)
Explanation
A bacterial plasmid is typically circular and double stranded. It is also called extra chromosomal DNA that can replicate in a cell separately from the chromosomes.
So, the correct answer is 'Can replicate independently'.
The basic procedure involved in the construction of a recombinant DNA molecule is depicted. The mistake in the procedure is?
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0%
Enzyme polymerase is not included
0%
Mammalian DNA is used
0%
Two different restriction enzymes are used
0%
The cut ends of vector and chromosomal DNA have staggering ends
Which of the following statements is incorrect about plasmids?
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0%
They are extrachromosomal DNA
0%
They are used in genetic engineering
0%
They help in the replication of nucleoid
0%
They are small, circular and confer certain unique phenotypic characters to some bacteria like resistance to antibiotics
Explanation
Plasmids are small, circular, extrachromosomal DNA which are able to self replicate. They are seen in certain bacteria. They usually contain some unique phenotypic characters to some bacteria like resistance to antibiotics. They are widely used in genetic engineering for transfer of desired gene. The transformants are identified due to presence of antibiotic resistance genes.
Thus, the correct answer is 'They help in the replication of nucleoid.'
During heat shock to the bacterium , the temperature used for giving thermal shock is:
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0%
$$82^oC$$
0%
$$109^oC$$
0%
Liquid nitrogen
0%
$$42^oC$$
Explanation
Heat Shock is given to bacteria for transformation that alters the membrane fluidity. The increase in temperature creates pores in the bacterial plasma membrane and allow plasmid DNA to enter the bacterial DNA. For the heat shock, the DNA-bacteria mixture is put into a 42C to 37C water bath.
Identify the correct sequence of steps in the construction of recombinant DNA.
$$(1)$$ use restriction enzymes
$$(2)$$ use DNA ligase
$$(3)$$ remove plasmid from parent bacterium
$$(4)$$ introduce plasmid into new host bacterium.
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0%
$$1-2-3-4$$
0%
$$4-3-2-1$$
0%
$$3-1-2-4$$
0%
$$2-3-1-4$$
Explanation
Generation of rDNA steps:
1) The DNA for insulin is first disengaged.
2) A plasmid made of DNA is expelled from a bacterial cell.
3) A limitation protein cuts the plasmid DNA open, leaving sticky finishes.
4) The insulin quality, with integral sticky closures, is included.
5) DNA ligase catalyst grafts (joins) together with the plasmid DNA and the Insulin DNA.
6) The plasmid (now hereditarily changed) is embedded again into the bacterium.
7) The bacterium has cell, partitions and delivers duplicates of the plasmid.
8) The Bacterium makes human insulin utilizing the quality in the plasmid.
9) The insulin is removed from the bacterial culture.
So, the correct option '
2−3−1−4'.
Selected the vectors which have the ability to incomplete a foreign DNA in chromosomal DNA of plant cell.
Report Question
0%
Disarmed Ti plasmid
0%
$$pBR322$$
0%
Bacteriophage
0%
Both (1) and (2).
Explanation
Vectors are the agent that helps in transporting the DNA to the host cell for multiplication of the alien DNA.
The choice of the vector can be a bacteriophage or plasmids. Bacteriophages infect bacteria and are a type of viruses.
pBR322 is a cloning vector for E.coli and is used for it.
The Ti plasmids which are obtained from Agrobacterium tumefaciens is the vector which is used to introduce new genes into plant cells.
It gets its name as tumour-inducing plasmid because it induces a tumour in the broadleaf plant.
So, the correct option is 'Disarmed Ti plasmid'.
How many fragments will be generated in total upon digestion of a closed circular DNA molecule and liner DNA molecule with a same restriction enzyme having six recognition sites on both DNA molecules?
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0%
$$13$$
0%
$$14$$
0%
$$12$$
0%
$$6$$
Explanation
Restriction endonucleases are a class of enzymes that cut the DNA by recognising a specific sequence or base pairing of the DNA.
These enzymes have a very important role in recombinant DNA techniques.
Linear DNA is the form of DNA present in the eukaryotic nucleus and is composed of two free ends. Circular DNA is predominantly found in prokaryotes, whereas the mitochondria, chloroplast and plasmids also contain circular DNA. Circular DNA is found in the cytoplasm of the prokaryotic cell, in mitochondria or in the chloroplast.
So when the restriction endonuclease will cut the DNA from the recognition site fragments of DNA will be produced. As the linear NA has 2 free ends it will produce 7 fragments and the circular DNA will produce 6 fragments.
So, the correct option is '13'.
Which of the following is not a feature of plasmid $$pBR322$$?
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0%
Double stranded circular DNA
0%
Autonomous replication
0%
Integrates with chromosomal DNA in host cell
0%
Absence of histones
Explanation
pBR322 is an important cloning factor which adds the DNA to the host cell. The pbr322 vector is a cloning vector for E.coli and it contains restriction sites for many restriction endonucleases such as Bam HI and EcoRI. This also has various cloning sites as well as selectable markers.
These vectors are generally single-stranded DNA molecules and they have the origin of replication sites which enables the replication of any piece of DNA when this is linked to the host cell.
So, the correct option is 'Double stranded circular DNA'.
E.coli cloning vector pBR322 showing restriction sites, ori and antibiotic resistance genes is given below. Select the correct option.
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0%
A-Hind III,B-Eco RI, C-Bam H I, D-Sal I
0%
A-Eco RI, B-Hind III, C-Bam HI, D-Sal I
0%
A-Eco RI, B-BamH I, C-Hind III, D-Sal I
0%
None of these
Explanation
The correct answer is 'A-Eco RI, B- Hind III, C- Bam HI, D-Sal I'.
Option B is correct.
Column I Column II
I. Agarose A. PCR
II. Opines B. Gene gun
III. Biolistic C. Ti plasmid
iv. Thermal cycler D. Sea weeds
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0%
$$I-D,II-A,III-B,IV-C$$
0%
$$I-D,II-C,III-B,IV-A$$
0%
$$I-D,II-A,III-C,IV-B$$
0%
$$I-A,II-D,III-B,IV-C$$
Explanation
Agarose is derived from seaweeds
Gelidium
and
Gracilaria
Opine synthesis is
the function
of Ti plasmid of
Agrobacterium
Biolistic is
the term
used for gene gun used for biotransformation
Thermocycler is used to carry out PCR reaction
So the correct option is B. (
I−D,II
−C
,II
I−B
,IV−A
)
Which of the following techniques can be used to introduce foreign DNA into the cell?
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0%
Using disarmed pathogen
0%
Microinjection
0%
Gene gun
0%
All of these
Explanation
Vectors, gene gun ( biolistic ) and microinjection are all viable techniques to insert foreign DNA into the host cell. So, the correct option is All of these.
Insertional inactivation is related to
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0%
Microinjection
0%
Gene gun
0%
Gel electrophoresis
0%
Selection of recombinations
Explanation
Insertional inactivation is the inactivation of a gene upon insertion of another gene inside in its place or within its coding sequence. This helps the selection of transformant and as well as recombinant colonies in selective antibiotic medium aided due to insertional inactivation of the antibiotic gene which becomes inactive due to foreign gene insert within its sequence.
So, the correct option is Selection of recombination.
The areas of application of PCR include
A. Production of monoclonal antibodies
B. Insertion of recombinant DNA into an organism
C. Diagnosis of specific mutation
D. Detection of plant pathogens
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0%
A, B
0%
B, C
0%
C, D
0%
A, B, C, D
Explanation
The areas of application of PCR include
Clinical Diagnosis
DNA Sequencing
Gene Manipulation and Expression Studies
in Comparative Studies of Genomes
in Forensic
Medicine
in Comparison with Gene Cloning
So, the correct option is '
C,D
'.
X technique is now routinely used to detect HIV in suspected AIDs patients. It is being used to detect mutations in genes in suspected cancer patients too. It is a powerful technique to identify many other genetic disorders. Identify X-
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0%
X=PCR
0%
X=DNA fingerprinting
0%
X-Bioinformatic
0%
X-X-ray defreaction
Explanation
The development of molecular techniques that access viral load and the development of genotypic resistance have revolutionized the treatment of HIV disease. Commercially available viral load assays use a number of different approaches from reverse transcriptase PCR to amplification of branched chain DNA. New real-time PCR assays are under development, including LightCycler- and TaqMan-based tests. So, the correct answer is option A. ( X=PCR ).
The first plasmid used for recombinant DNA technology is obtained from
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0%
Bacillus thuringiensis
0%
Thermus aquaticus
0%
Salmonella typhimurium
0%
E. coli
Which of the following is not a source of restriction endonuclease?
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0%
Haemophilus influenza
0%
Escherichia coli
0%
Agrobacterium tumefaciens
0%
Bacillus amyloli
Explanation
Agrobacterium tumefaciens is a pathogen of several dicot plants. It delivers a piece of DNA known as T-DNA' in the Ti plasmid which transforms normal plant cells into tumor cells to produce chemicals against pathogens.
The restriction enzyme Eco Rl, is isolated from Escherichia coli RY13. The first restriction enzyme Hind II was isolated from the bacterium Haemophilus influenzas.
The restriction enzyme Bam HI is isolated from Bacillus amyloli.
So, the correct option is option C.
In E.coli, a finished polypeptide has $$162$$ amino acids of which the first amino acid is not methionine compound. How many nucleotides of DNA are required to code this polypeptide?
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0%
$$486$$
0%
$$54$$
0%
$$489$$
0%
$$492$$
Explanation
There is an intimate connection between genes and synthesis of polypeptides or enzymes The relationship between the sequence, of amino acids in a polypeptide and nucleotide sequence of DNA or mRNA is called genetic code. To code a polypeptide of 162 amino acids 486 nucleotides required but here, methionine is absent. Therefore, 489 nucleotides required and methionine may remove from polypeptide later.
So, the correct option is option C.
The technique in which a foreign DNA is precipitated on the surface of the tungsten or gold particle and shot into target cells is known as?
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0%
Microinjection
0%
Chemical - mediated genetic transformation
0%
Electroporation
0%
Biolistic method
Explanation
In microinjection, a glass-made micropipette is used for DNA transfer.
The chemical-mediated genetic transformation uses chemical agents.
In Electroporation, the target cells are mixed and treated with an electric field to create pores for DNA entry.
In the biolistic method or gene gun method, the foreign DNA is precipitated over the surface of metals like; gold or tungsten, and bullets are prepared.
These bullets are then fired into the solution of target cells. This foreign DNA gets inserted and helps in the production of desired products.
So, the correct option is option D.
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Practice Class 12 Medical Biology Quiz Questions and Answers
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