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CBSE Questions for Class 12 Medical Biology Biotechnology: Principles And Processes Quiz 5 - MCQExams.com
CBSE
Class 12 Medical Biology
Biotechnology: Principles And Processes
Quiz 5
The organism, which is used for gene transfer in higher organism is
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0%
Agrobacterium tumefaciens
0%
E.coli
0%
Acetobacter aceti
0%
Bacillus thuringiensis
Explanation
Agrobacterium tumefaciens
is a pathogen of several dicot plants. It is used for the gene transfer in higher organisms. It is able to deliver a piece of DNA known as 'T-DNA' to transform normal plant cells into a tumor and direct these tumor cells to produce the chemicals required by the pathogen. This bacterium invades plants at the site of wound, transforming them and nearby cells to form a tumor called crown gall.
Enzymes used in breaking DNA at specific sites are
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0%
DNA-ases
0%
Endonucleases
0%
Restriction endonucleases
0%
Exonucleases
Explanation
Restriction enzymes are used in genetic engineering for gene manipulation. It cuts DNA base pairs at specific sites. They cut the base pairs within the molecule so they are named as an endonuclease. 3000 restriction enzyme has been discovered till now. They are known as molecular scissors as they are used to cut a single gene from a larger piece of DNA. The restriction enzyme Eco RI, Bam II and Hind Ill are used in recombinant DNA technology to produce cuts in vector and other DNA molecules to obtain chimeric DNA.
So, the correct answer is option C.
Restriction enzymes are used to cut
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0%
Single stranded RNA
0%
Double stranded DNA
0%
Single stranded DNA
0%
Double stranded RNA
Explanation
Restriction enzymes are used in genetic engineering for gene manipulation. It cuts DNA base pairs at specific sites. They cut the base pairs within the molecule so they are named as an endonuclease. 3000 restriction enzyme has been discovered till now. They are known as molecular scissors as they are used to cut a single gene from a larger piece of double stranded DNA.
The restriction enzyme Eco RI, Bam II and Hind Ill are used in recombinant DNA technology to produce cuts in vector and other DNA molecules to obtain chimeric DNA.
So, the correct answer is option B.
In retroviruses, RNA dependent DNA polymerase synthesizes
Report Question
0%
DNA
0%
RNA
0%
RNA-DNA
0%
None of the above
Explanation
C. RNA-DNA
Solution : In retroviruses they can synthesize the DNA from RNA template in the host by help of reverse transcriptase that is RNA dependent DNA polymerase.
So the correct answer is " RNA-DNA"
Transfer of DNA bands from agarose gel to nitrocellulose or nylon membrane is
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0%
Southern transfer
0%
Western transfer
0%
Northern transfer
0%
Eastern transfer
0%
Gene transfer
Explanation
A. Southern Transfer
Solution : Southern Transfer is the process developed by Southern to transfer the DNA bands from agarose gel to nitrocellulose membrane in order to obtain a autoradiograph and visualize the bands under X ray.
So the correct answer is"
Southern Transfer"
Identify palindromic sequence
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0%
G
A
A
T
T
C
C
U
U
A
A
G
0%
G
A
A
T
T
C
C
T
T
U
U
G
0%
G
A
A
T
T
C
C
T
T
A
A
G
0%
G
A
A
T
T
C
G
A
A
T
I
C
Explanation
C .
G
A
A
T
T
C/
C
T
T
A
A
G
Solution : Palindromic sequence is the sequence of DNA bases which when read from the 5' end to 3' end is same when read from 3' end to 5 ' end.
So the correct answer is
G
A
A
T
T
C/
C
T
T
A
A
G
Common reporter gene used in plant expression vector is _______.
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0%
TAC
0%
GAT
0%
CAT
0%
TAG
In DNA segment of six coils, 22 bp are linked by two hydrogen bonds. How many cytosine bases would be present
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0%
22
0%
38
0%
44
0%
76
Explanation
Since, one complete turn of the double helix has 10 base pairs, 6 coils of DNA will have 10x6= 60 base pairs.
According to the question, there are 22 base pairs with two hydr
ogen
bonds which mean that out of total 60 base pairs in that DNA segment, the number of A-T pairs is 22;
the number of adenine = 22 and the number of thymine = 22;
Thus, number of G-C pairs = 60-22 = 38;
number of guanine = 38 and number of cytosine = 38;
So the correct answer is option B.
Who developed polymerase chain reaction technique and got Nobel Prize
Report Question
0%
Muller
0%
Mullis
0%
Wilson
0%
Nirenberg
Explanation
B. Mullis
Solution : Kary mulis developed the polymerase chain reaction that involved amplifying a small amount of DNA by series of polymerase chain reactions to get a large amount of DNA.
So the correct answer is"Mullis"
Thermal cycler is used in the reaction is
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0%
Radioacivity
0%
Enzyme catalyzed reaction
0%
Chemical reaction
0%
Polymerase chain reaction
Explanation
Polymerase chain reaction is a technique which is mainly used to
amplify
a DNA segment. It was given by Kary Mullis. The sample DNA strand is denatured by heating at the temperature of 95
o
C. Each strand act as a template for the new strand. The primers are annealed at 55
o
C
to all the template.
In the third step, the temperature is raised to about 72
o
C
and the DNA polymerase also known as Taq polymerase begins adding nucleotides onto the ends of the annealed primers.
The thermal cycler is an instrument with microprocessor-controlled temperature cycling required for polymerase chain reaction. It is a technique discovered in 1975 for recombinant DNA and gene cloning. The device has a thermal block with holes where tubes with the PCR reaction mixtures can be inserted. The cycler then rises and lowers the temperature of the block in discrete, pre-programmed steps.
So, the correct answer is option D.
Restriction enzymes are used in genetic engineering and
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0%
Cut DNA base pairs at specific sites
0%
Cut DNA base pairs at variable sites
0%
Join two DNA segments
0%
Cut RNA base pairs at specific sites
Explanation
Restriction enzymes are used in genetic engineering for gene manipulation. It cuts DNA base pairs at specific sites. They cut the base pairs within the molecule so they are named as an endonuclease. 3000 restriction enzyme has been discovered till now. They are known as molecular scissors as they are used to cut a single gene from a larger piece of DNA.
So, the correct answer is option A.
Polymerase chain reaction is used for
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0%
In vivo replication
0%
In vivo synthesis of mRNA
0%
In vitro replication of DNA segment
0%
In vitro synthesis of mRNA
Explanation
C. In vitro replication of DNA segment
Solution : Polymerase chain reaction is the process by which the DNA segment is replicated from a small amount into a large number inside a PCR reactor.
So the correct answer is "
In vitro replication of DNA segment"
Blood stain component to be used for DNA profiling technique is
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0%
Serum
0%
Leucocytes
0%
Platelets
0%
Erythrocytes
Explanation
B. leucocytes
Solution : leucocytes are the only components that have nucleus . Platelets and erythrocytes do not have nucleus . Serum is the solute and solvent component of blood that does not contain clotting elements and cellular components. The leucocytes are used for the DNA profiling by the DNA isolated from the leucocyte nucleus.
So the correct answer is " Leucocytes"
Which one of the following statements is wrong with respect to separation of DNA fragments on gel electrophoresis?
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DNA fragments move towards anode under electric field through the matrix.
0%
The commonly used matrix is agarose gel.
0%
DNA fragments resolve according to their size.
0%
The smaller DNA fragments remain close to cathode.
Explanation
Solution : During the gel electrophoresis DNA fragments are separated on agarose gel. The electric field is applied and the DNA fragments as they are negatively charged moves towards the positive electrode or the anode. They are separated according to their sizes and the smaller ones are separated first and move towards anode.
So, the correct answer is option D.
Which ones are simple sequence repeats (SSRs)
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Minisatellite sequences
0%
Microsatellites
0%
Pseudogenes
0%
Multiple gene family.
Explanation
Simple sequence repeats (SSRs), sometimes described as genetic 'stutters,' are DNA tracts in which a short base-pair motif is repeated several to many times in tandem (e.g. CAGCAGCAG). These sequences experience frequent mutations that alter the number of repeats similar to Multigene Family, a set of genes descended by duplication and variation from some ancestral gene.
So, the correct answer is 'Multiple gene family.'
PCR and RFLP are employed in ________.
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0%
DNA sequencing
0%
Genetic engineering
0%
Study of enzymes
0%
Genetic transformation
Explanation
B. Genetic engineering
Solution : PCR and RFLP is used in detecting the genome of an unknown organism from a very small amount of DNA. PCR can amplify the DNA into a large amount and RFLP is used to analyze the DNA based on their restriction maps.
So the correct answer is "Genetic engineering".
During gene amplification the mixture of sample DNA, nucleotides and polymerases is heated to
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Activate polymerases
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Activate nucleotides
0%
Separate sense and antisense DNA strands
0%
Provide energy for different strands
Explanation
PCR is an enzymatic process in which a specific region of DNA is replicated over and over again to yield many copies of a particular sequence. This molecular “xeroxing” process involves heating and cooling samples in a precise thermal cycling pattern over ≈30 cycles which causes to separate sense and antisense DNA strands.
So, the correct answer is 'Separate sense and antisense DNA strands.'
In a DNA fragment, there are 8 turns with 40% of the bases are cytosine. What would be the number of hydrogen bonds present in this DNA fragment
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0%
96
0%
192
0%
224
0%
60
Explanation
Number of pair of nucleotide in 1 major groove=10
Restriction endonuclease, in DNA finger printing, carries out following process
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Fragmentation of DNA
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Getting copies of DNA
0%
Loading DNA on agarose plate
0%
Synthesis of DNA
Explanation
A. Fragmentation of DNA
solution : Restriction endonuclease is used for cutting the DNA into fragments before loading them into agarose gel for electrophoresis before DNA fingerprinting.
So the correct answer is "
Fragmentation of DNA"
Escherichia coli
, in which both the strands of DNA are labeled with
15
N
is transferred to
14
N
medium and allowed to replicate for three generations. Find out the number of hybrid DNA molecules in the third generation
Report Question
0%
8
0%
2
0%
12
0%
10
Explanation
Messelson and Stahl in 1953 performed the experiment to find the semiconservative nature of DNA. They have taken
Escherichia
coli
and grown into the nutrient medium. First, they have added heavy nitrogen
N
15
in the medium for the growth of bacteria and then transferred it to light nitrogen
N
14
and allowed to grow. They were grown for several generations in both the mediums. During the stages of DNA duplication they have taken the strain of bacteria and make it undergo centrifugation, the heavier ones settle down while lighter ones at the top. There were four generations in which third generation have two hybrid DNA molecule that were observed as described in the figure.
The whole cycle of gene amplification requires
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0%
15 minutes
0%
30 minutes
0%
3 hours
0%
24 hours.
Explanation
The denaturation stage of PCR takes about 1–2 minutes. The thermocycler then lowers the temperature to about 50° to 60°C, which allows the short, oligonucleotide primers to anneal to their complementary sequences on the single-stranded DNA molecules. The annealing stage of PCR lasts about 30 seconds. Hence, the whole cycle of gene amplification requires 30 minutes.
So, the correct answer is '30 minutes.'
Which palindromic base sequence is cut at the middle by a restriction enzyme
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0%
5
′
−
C
G
T
T
C
G
−
3
′
3
′
−
C
C
A
A
G
C
−
5
′
0%
5
′
−
G
A
A
T
T
C
−
3
′
3
′
−
C
T
T
A
A
G
−
5
′
0%
5
′
−
C
T
A
C
T
G
−
3
′
3
′
−
G
T
G
C
A
A
−
5
′
0%
3
′
−
C
G
A
A
T
G
−
5
′
5
′
−
C
G
A
A
T
G
−
3
′
Explanation
A palindromic sequence is a sequence of DNA that is the exact same when read from 5' to 3' and from 3' to 5'.
5
′
−
G
A
A
T
T
C
−
3
′
3
′
−
C
T
T
A
A
G
−
5
′
In this DNA sequence the bases are same if the orientation kept same.
So the correct answer is option B.
Elution means?
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Separation of DNA fragments on agarose gel
0%
Cutting and extraction of DNA bands from the agarose gel
0%
Making the DNA bands visible under UV radiation
0%
Isolation of alien DNA from the choice organism
Explanation
B.
Cutting and extraction of DNA bands from the agarose gel.
Solution : Cutting and extraction of DNA is done to separate the DNA from the gel in which it is collected. Water or a low salt buffer is added to break the cation bridge and dislodge the DNA from the gel and elute it.
So the correct answer is "
B.
Cutting and extraction of DNA bands from the agarose gel."
The technique in which foreign DNA is precipitated over surface of metal particles for passing into target cells is __________.
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0%
Microinjection
0%
Electroporation
0%
Particle gun
0%
Chemical mediated gene transfer
Explanation
The Particle bombardment device, also known as the gene gun, was developed to enable penetration of the cell wall so that genetic material containing a gene of interest can be transferred into the cell. The particle bombardment starts with coating tungsten or gold particles with plasmid DNA.
So, option C is the correct option.
Advancement in genetic engineering has been possible due to discovery of
Report Question
0%
Oncogenes
0%
Transposons
0%
Restriction endonuclease
0%
Exonucleases
Explanation
A restriction enzyme, restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.
Without the discovery of Restriction endonuclease, the cutting of DNA would not have been possible. Hence, the advancement in genetic engineering not all, but a major part was due to restriction endonuclease.
So, option C is the correct option.
Restriction enzymes are used in genetic engineering because they
Report Question
0%
Can join DNA fragments
0%
Cut DNA at specific base sequence
0%
Cut DNA at variable sites
0%
Are proteolytic enzymes which degrade harmful proteins
Explanation
So the correct option is B.
Gene gun can introduce genes into cells with the help of
Report Question
0%
Plasmids
0%
Cosmids
0%
Microscopic pellets
0%
Phagemids
Explanation
In the gene gun method, microscopic pellets of gold or tungsten are coated with the transgene fragments and shot into the plant cells or tissues
at high velocity
.
So the correct option is C.
Endonucleases break DNA at specific sites called
Report Question
0%
Palindromic sequences
0%
Restriction sites
0%
Conserved sites
0%
Both A and B
Explanation
Restriction enzyme, also called restriction endonuclease, a protein produced by bacteria that cleaves DNA at palindromic sequences and restriction sites along the molecule. In bacterial enzymes cleave foreign DNA, thus eliminating infecting organisms.
So, option D is the correct option.
Bacterial resistance to antibiotics is a genetic trait. It is normally carried by.
Report Question
0%
Centromere
0%
Plasmid
0%
Chromosome
0%
Intron
Enzyme that cuts DNA at specific sites is
Report Question
0%
DNA ligase
0%
Restriction endonuclease
0%
DNA polymerase
0%
Reverse transcriptase
Explanation
A restriction enzyme, restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. Restriction enzymes are one class of the broader endonuclease group of enzymes.
So, option B is the correct option.
Arber, Smith and Nathans are famous for discovery of
Report Question
0%
Gene therapy
0%
Restriction enzyme
0%
Humulin
0%
Second generation vaccines
Restriction endonuclease is employed for cutting
Report Question
0%
A single stranded DNA
0%
Double stranded DNA
0%
RNA fragment
0%
mRNA
Explanation
So the correct option is B.
Which enzyme is useful in genetic engineering?
Report Question
0%
DNA-ase
0%
Amylase
0%
Lipase
0%
Restriction endonuclease
Explanation
A restriction enzyme, restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.
So, option D is the correct option.
Plasmids are vectors for gene cloning because they
Report Question
0%
Self replicate in bacterial cells
0%
Replicate freely outside bacterial cells
0%
Can be multiplied in culture
0%
Can be multiplied in laboratories using enzymes
Explanation
Scientists have taken advantage of plasmids to use them as tools to clone, transfer, and manipulate genes. Researches can insert DNA fragments or genes into a plasmid vector, creating a so-called recombinant plasmid. This plasmid can be introduced into a bacterium by way of the process called transformation.
So, option A is the correct option.
Enzyme required for polymerase chain reaction (PCR) is
Report Question
0%
RNA polymerase
0%
Ribonuclease
0%
Taq polymerase
0%
Endonuclease
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, option C is the correct option.
Restriction endonucleases are
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0%
Used in genetic engineering for uniting two DNA molecules
0%
Used for in vitro DNA synthesis
0%
Present in mammalian cells for degeneration of DNA of dead cells
0%
Synthesised by bacteria for their defence
Explanation
Correct Option: D
Explanation:
Endonucleases
identify certain sequences in incoming DNA and digest it into pieces.
They either cut the
DNA
at specified locations or more randomly.
As a result,
bacteria
produce restriction endonucleases as part of their defence mechanism.
Hence, Restriction Endonuclease are synthesised by bacteria for their defence.
Restriction endonucleases are useful in
Report Question
0%
Breaking DNA at specific sites
0%
Creating sticky ends
0%
Both A and B
0%
Crossing over
Chemical knives/molecular scissors/genetic scalpels of DNA are
Report Question
0%
Restriction endonucleases
0%
Polymerases
0%
Ligases
0%
Transcriptases
Explanation
A restriction enzyme, restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. In the bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms. Restriction endonuclease is also known as molecular scissors as it cuts the DNA at the restriction sites.
So, option A is the correct option.
Extrachromosomal DNA used as vector in gene cloning is
Report Question
0%
Transposon
0%
Intron
0%
Exon
0%
Plasmid
Explanation
The most commonly used cloning vectors are
E.coli
plasmids, small circular DNA molecules that include three functional regions:
(1) an origin of replication,
(2) a drug-resistance gene, and
(3) a region where DNA can be inserted without interfering with plasmid replication or expression of the drug-resistance genes.
So, option D is the correct option.
Genetic engineering has been made possible due to
Report Question
0%
Observation of DNA under electron microscope
0%
We can break DNA at specific points by DNA-ases
0%
Availability of restriction endonucleases in purified form
0%
Knowledge of transduction
Explanation
Genetic engineering has been made possible due to availability of restriction endonucleases in purified form. Restriction endonuclease is an enzyme that cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites. In bacterial cell, restriction enzymes cleave foreign DNA, thus eliminating infecting organisms.
So, option C is the correct option.
Structure involved in genetic engineering is
Report Question
0%
Plastid
0%
Restriction endonuclease
0%
DNA polymerase I
0%
Prochromosome
Explanation
The structure involved in genetic engineering is
Restriction endonuclease. So
the correct option is B.
Endonuclease is employed in
Report Question
0%
Transcription
0%
Translation
0%
Genetic engineering
0%
DNA replication
Thermal cycle is used in
Report Question
0%
Radioactivation
0%
Chemical reaction
0%
Polymerase chain reaction
0%
Enzyme catalysed reactions
Explanation
The thermal cycler is a laboratory apparatus most commonly used to amplify segments of DNA via the polymerase chain reaction (PCR). The cycler then raises and lowers the temperature of the block in discrete, pre-programmed steps.
So, option C is the correct option.
Identify the plasmid
Report Question
0%
EcoRI
0%
pBR 322
0%
AIUI
0%
Hind III
Explanation
The pBR322 plasmid is an E. coli vector. It was constructed in the year 1977 in the laboratory of Herbert Boyer. In pBR322, the p stands for “plasmid” and the B and R for "Bolivar" and "Rodriguez”, respectively. It is 4361 base pair long and contains ampicillin and tetracycline resistance genes.
So, the correct answer is '
pBR322'.
Plasmids are suitable vectors for gene cloning because they are ________.
Report Question
0%
Small circular DNA molecules with their own origin of replication site
0%
Small circular DNA molecules which can integrate with host chromosomal DNA
0%
Having antibiotic genes
0%
Able to shuttle between prokaryotic and eukaryotic cells
The most extensively used bacteria in genetic engineering is ____________.
Report Question
0%
Bacillus
0%
Clostridium
0%
Escherichia
0%
Salmonella
Explanation
Artificial gene manipulation is known as genetic engineering. The bacterium
Escherichia coli
is widely used in genetic engineering experiments as:
(1) Human insulin chains are synthesized within the
E.coli
.
(2) Hormone somatostatin is also produced within the bacterium
E. coli
.
So, option C is the correct option.
Electroporation is
Report Question
0%
Making transient pores in cell membranes to introduce gene constructs
0%
Fast passage of nutrients through phloem sieve pores by electric stimulation
0%
Opening of stomata by artificial light during night
0%
Purification of saline water with the help of membrane system
Explanation
Electroporation is now used to transfer the foreign DNA into the fragile cells. The electric pulses induce the formation of large pores in the cell membrane.
These pores give a passage through which the foreign DNA can enter into the protolasts and thus, increase the transformation frequency.
So, option A is the correct option.
Restriction endonucleases used widely in RDT are obtained from ____________.
Report Question
0%
Plasmids
0%
Bacterial cells
0%
Bacteriophages
0%
All prokaryotic cells
Explanation
Restriction endonucleases are called as molecular scissors. It is because of the special feature of these enzymes to cut at desired sites of DNA in the technique of genetic engineering. These are obtained from all prokaryotic cells.
So, option D is the correct option.
In gel electrophoresis, differential mobility of DNA depends upon
Report Question
0%
Helical nature of DNA
0%
Double stranded nature of DNA
0%
Charge and size of DNA
0%
Hydrogen bonding between bases
Explanation
Gel electrophoresis is a method for separation and analysis of DNA, RNA and proteins and their fragments based on their size and charge and in biochemistry and in molecular biology to separate a mixed population of DNA and RNA fragments by length, to estimate the size of DNA and RNA fragments or to separate proteins by charge.
So, option C is the correct option.
Fragments of DNA formed after treatment with endonucleases are separated by the technique
Report Question
0%
Polymerase chain reaction
0%
Southern blotting
0%
Colony hybridisation
0%
Electrophoresis
Explanation
Gel electrophoresis uses a positively charged grid to attract the negatively charged DNA fragments, thereby separating them by size, because the smaller ones will migrate the most. Radioactive or fluorescent probes are added, which attract and bind with the desired DNA to produce visible bands.
So, option D is the correct option.
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