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CBSE Questions for Class 12 Medical Biology Biotechnology: Principles And Processes Quiz 11 - MCQExams.com
CBSE
Class 12 Medical Biology
Biotechnology: Principles And Processes
Quiz 11
Which one of the following is a case of wrong matching.
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Somatic hybridization - Fusion of two diverse cells
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Vector DNA - Site for tRNA synthesis
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Micropropagation - In-vitro production of plants in large numbers.
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Callus - Unorganised mass of cells produced in tissue culture.
Explanation
Somatic hybridization also called as protoplast fusion, is a type of genetic modification in plants by which two distinct species of plants are fused together to form a new hybrid plant with the characteristics of both, a somatic hybrid.
Micropropagation is the practice of rapidly multiplying stock plant material to produce a large number of progeny plants, using modern plant tissue culture methods.
Callus is an unorganised mass of cells produced in tissue culture.
A cloning vector is a small piece of DNA, taken from a virus, a plasmid, or the cell of a higher organism, that can be stably maintained in an organism, and into which a foreign DNA fragment can be inserted for cloning purposes. It is not a site for t-RNA synthesis.
So, the correct answer is option B.
This method of finding a gene is used when researchers know very little about the gene they are trying to find. This process results in a complete gene library: a collection of copies of DNA fragments that represent the entire genome of an organism. This process is called as
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RFLP
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Shotgun cloning
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Gene synthesis cloning
0%
PCR
Explanation
Shotgun cloning is a technique that involves sequencing of gene when only little information is available about the gene. In this, entire DNA is cut into numerous fragments either using restriction enzymes or by physical method. These DNA fragments are then sequenced individually by inserting these fragments into bacteria or yeast with plasmids. It has been used to sequence the mouse, fly and human genomes. Hence, it results in a complete gene library.
Thus, the correct answer is option B.
Ti-plasmid naturally occurs in
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Agrobacterium
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Corynebacterium
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Staphylococcus
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Vibrio
Explanation
A Ti- or tumour inducing plasmid is a circular plasmid present in the cells of the bacterium
Agrobacterium tumefaciens
and
Agrobacterium
rhizogenes
. These bacteria
use the plasmid genes to transduce its genetic material and desired genes into the plants.
Thus, the correct answer is option A.
5'-GAATTC-3' is the recognition site, for which of the following restriction endonuclease?
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Hind III
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EcoRI
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Bam I
0%
Hae III
Explanation
EcoRI is the restriction enzyme, derived from
Escherichia coli,
strain R and is the first to be isolated.
EcoRI recognizes and cuts at the specific restriction site 5'-GAATTC-3' and produces sticky ends.
This is the common enzyme that is used as a tool for the restriction of the bacterial plasmid and desired genes in molecular biology techniques.
Thus, the correct answer is option B.
pBR322, which is frequently used as a vector for cloning gene in
E. coli
is a/an
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Original bacterial plasmid
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Modified bacterial plasmid
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Viral genome
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Transposon
Explanation
pBR322 is a plasmid and was one of the first widely used
E.coli
cloning vectors. It is a modified bacterial plasmid, created in 1977. It contains tetracycline and ampicillin antibiotic resistant gene which allows the bacteria to grow in particular antibiotic-containing medium.
A piece of nucleic acid used to find a gene by forming a hybrid with it, is called as
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Vector
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Probe
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Retrovirus
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Restriction sequence
Explanation
Nucleic acid hybridization is a fundamental tool in molecular genetics which takes advantage of the ability of individual single-stranded nucleic acid molecules to form double-stranded molecules (to hybridize to each other). Standard nucleic acid hybridization assays involve using a labelled nucleic acid probe to identify related DNA or RNA molecules (ones with a significantly high degree of sequence similarity) within a complex mixture of unlabelled nucleic acid molecules, the target nucleic acid.
Agarose which is extracted from sea weeds is most widely used in
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Gel electrophoresis
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Spectrophotometry
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Tissue culture
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PCR
Explanation
Agarose is the supporting structure in the cell walls of certain species of algae and which is released on boiling. Agarose is a polysaccharide polymer extracted from seaweed. Slabs of agarose gels are used for electrophoresis.
Thus, the correct answer is option A.
A virus that can reproduce without killing its host is called as
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Lytic virus
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Temperate virus
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Virion
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All of the above
Explanation
Temperate viruses are those that reproduce without killing their host cell. They reproduce in two ways: through the lytic cycle and the lysogenic cycle. In the lysogenic cycle, the phage's DNA recombines with the bacterial chromosome. Once it has inserted itself, it is known as a prophage. A host cell that carries a prophage has the potential to lyse, thus it is called as a lysogenic cell.
Which one among the following is just a cloning plasmid and not a expression plasmid?
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pBAD-18-Cam
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pBCSK
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pUC19
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pET
Explanation
Cloning plasmids are the plasmids that serve to carry the foreign DNA segment into the host cell while expression plasmids carry expression signals also to ensure maximum expression of the foreign gene.
pBAD-18-Cam, pBCSK and pET are expression plasmids carrying strong promoter and termination codons to ensure maximum gene expression.
pUC19 is a cloning vector-only and does not carry the sequences to facilitate gene expression.
Thus, the correct answer is option C.
A gene carried by recombinant DNA is cloned when
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Its host bacterium divides by binary fission.
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It is transcribed.
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It is fragmented by restriction enzymes.
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It is hybridized.
Explanation
Recombinant DNA and gene cloning are essential tools for research in molecular microbiology and medicine. They have many medical applications, including development of new vaccines, biologics, diagnostic tests and therapeutic methods.
The genetic material of bacteria and plasmids is DNA. Bacterial viruses (bacteriophages or phages) have DNA or RNA as genetic material. The two essential functions of genetic material are replication and expression. Genetic material must replicate accurately so that progeny inherit all of the specific genetic determinants (the genotype) of the parental organism.
Replication of chromosomal DNA in bacteria starts at a specific chromosomal site called as the origin and proceeds bidirectionally until the process is completed. When bacteria divide by binary fission after completing DNA replication, the replicated chromosomes are partitioned into each of the daughter cells.
The origin region specifically and transiently associate with the cell membrane after DNA replication has been initiated, leading to a model whereby membrane attachment directs separation of daughter chromosomes (the replicon model).
Ideal host for the amplification of DNA molecules is
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Viruses
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Plants
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Bacteria
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Animals
Explanation
Bacteria are ideal for the amplification of DNA because of 2 reasons; their short doubling time; and availability extensive knowledge and tools for manipulating the bacteria. The short doubling time is advantageous because it will provide enough amounts of amplified DNA (of our interest) in a short span of time. The fact that tools are available helps us to amplify a variety of DNA molecules.
So, the correct answer is '
Bacteria'
Plasmids are naturally occurring
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Linear single stranded DNA
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Linear single stranded RNA
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Linear duplex DNA
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Circular duplex DNA
Explanation
A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small, circular, double-stranded DNA molecules. In nature, plasmids often carry genes that may benefit the survival of the organism. Example: antibiotic resistance.
The phenomenon by which the phage DNA exists as a part of the host DNA is called as
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Lytic cycle
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Lysogeny
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Episome
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Prophage
Explanation
The phenomenon by which the phage DNA exists as part of the host DNA is known as lysogeny. The latent form of the virus genome remains within the host but does not destroy it, is called as the prophage.
Episome is a genetic element inside some bacterial cells, especially the DNA of some bacteriophages, that can replicate independently of the host and also in association with a chromosome with which it becomes integrated.
The lytic cycle is one of the two cycles of viral reproduction, the other being the lysogenic cycle. The lytic cycle results in the destruction of the infected cell and its membrane.
Thus, the correct answer is option B.
.................. is the natural defence of bacteria against invading phages.
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Prophages
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Interferons
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Restriction enzymes
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All of the above
Explanation
A prophage is a bacteriophage genome which is inserted and integrated into the circular bacterial DNA chromosome or existing as an extrachromosomal plasmid. This is a latent form of a phage, in which the viral genes are present in the bacterium without causing disruption of the bacterial cell. Sometimes prophages may provide benefits to the host bacterium while they are dormant by adding new functions to the bacterial genome in a phenomenon called lysogenic conversion. Examples are the conversion of harmless strains of
Corynebacterium diphtheriae
or
Vibrio cholerae
by bacteriophages to highly virulent ones, which cause Diphtheria or cholera, respectively
The plasmid derived from $$E.\,coli$$ is
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pBR327
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pBR322
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Both (A) and (B)
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None of the above
Explanation
Simplest cloning vectors based on small bacterial plasmids are the most widespread in gene cloning experiment. A large number of different plasmid vectors are available for use with
E. coli
and these vectors combine ease of purification with desirable properties such as high transformation efficiency, convenient selectable markers for transformants and recombinants, and the ability to clone reasonably large pieces of DNA. One of the most popular vector used in gene cloning is pBR322. pBR327 plasmid is a higher copy number plasmid and was constructed by removing a 1089 bp segment from pBR322. Thus, the correct answer is option C.
A T$$_4$$ bacteriophage has a gene for the enzyme, lysozyme. The function of this enzyme is to digest the bacterial
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Cell wall
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Cell membrane
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Golgi
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Plasmid
Explanation
T$$_4$$ lysozyme helps to release mature phage particles from the cell wall by breaking down the peptidoglycan. The enzyme hydrolyses the 1,4-$$\beta$$ linkages between N-acetyl-D-glucosamine and N-acetylmuramic acid in peptidoglycan heteropolymers of prokaryotic cell walls.
The RTF region enables the plasmid to
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Be transmitted to other bacteria by conjugation
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Undergo transformation
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Replicate in the host cell
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Code for enzymes that inactivate specific drugs
Explanation
Resistance or R plasmid is a circular DNA which consists genes that make the bacterium antibiotic resistant.
Such a plasmid consists of two segments of DNA, one is responsible for replication as well as the transfer of R plasmid, and the second have the genes that produce substance neutralizing the action of one or another antibiotics or other drugs. These plasmids are conjugative and spread among the bacteria through conjugation.
Therefore, the correct answer is option A.
Which of the following plasmid does not show resistant to ampicillin?
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pBR327
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pBR322
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PUC
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None of the above
Explanation
pBR322 carries two sets of antibiotic resistance genes. pBR327 plasmid is a higher copy number plasmid and was constructed by removing a 1089 bp segment from pBR322. pUC8 plasmid is derived from pBR322, remaining only the replication origin and the ampR gene. Either ampicillin or tetracycline resistance can be used as a selectable marker for cells containing all the three plasmids, and each marker gene includes unique restriction sites that can be used in cloning experiments.
Thus, the correct answer is option D.
The sticky ends of a fragmented DNA molecule are made up of
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Calcium salts
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Endonuclease
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Unpaired bases
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Methyl groups
Explanation
The simplest DNA end of a double-stranded molecule is called a blunt end.
In a blunt-ended molecule, both strands terminate in a base pair.
Non-blunt ends are created by various overhangs.
An overhang is a stretch of unpaired nucleotides at the end of a DNA molecule.
These unpaired nucleotides can be in either strand, creating either 3' or 5' overhangs. Longer overhangs are called cohesive ends or sticky ends.
Therefore, the correct answer is option C.
Ti plasmid is useful in
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Bringing new genes into animal cells
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Bringing new genes into plant cells
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Bringing tumour cells into plant cells
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All of the above
Explanation
A Ti or tumour inducing plasmid is a circular plasmid that causes tumour or crown gall disease by direct injection of genetic material. Because of this property, it is used as the genetic equipment.
Agrobacterium tumefaciens
and
Agrobacterium rhizogenes
are used to transduce their genetic material to plants.
Therefore, the correct answer is option B.
pBR322 vector was produced by
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Bolivar.
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Rodriguez.
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Milstein and Kohler.
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Both A and B.
Explanation
Simplest cloning vectors based on small bacterial plasmids are the most widespread in gene cloning experiment. One of the most popular vector used in gene cloning is pBR322, and its nomenclature is pBR322 plasmid, p- A plasmid, BR. The laboratory in which the vector was originally constructed (Bolivar and Rodriguez, the two researchers who developed pBR322), 322- this number distinguishes the plasmid from other plasmids developed in the same laboratory.
Therefore, the correct answer is option D.
PCR method is useful for
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Amplification of DNA for forming billions of copies of itself.
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Monoclonal antibody production.
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Both of (A) and (B).
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None of the above.
Explanation
The polymerase chain reaction (PCR) is a technology in molecular biology used to amplify a single copy and to make multiple copies of the same fragment of the DNA. The two strands are separated and each strand is considered as the template strand for the synthesis of the new strand. In this way, many cycles are performed to produce multiple copies.
Thus, the correct answer is option A.
Many copies of a DNA molecule in test tube are produced by
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Polymerase chain reaction (PCR)
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Molecular chain reaction (MCR)
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Ephemeral chain reaction (ECR)
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All of the above
Explanation
PCR (Polymerase Chain Reaction) is a method to amplify the single copy of DNA into the thousand copies. In this method, DNA polymerase synthesizes new strand of DNA complementary to the offered template strand.
Therefore, the correct answer is option A.
Restriction enzymes are
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Not always required in genetic engineering
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Essential tools in genetic engineering
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Nucleases that cleave DNA wherever it contains a particular short sequence of nucleotides
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Both B and C
Explanation
A restriction enzyme is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. These are the enzymes which are used in the genetic engineering techniques for the cleavage of the desired gene and the vector. Restriction enzymes recognize a sequence and produce a double-stranded cut in the DNA. All types of enzymes recognize specific short DNA sequences and carry out the endonucleolytic cleavage of DNA to give specific fragments with terminal 5'-phosphates.
Thus, the correct answer is option D.
The plasmid called as recombinant plasmid and used for introduction of large genome to host cells is?
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Lamda
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2μ plasmid
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Cosmid
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Fertility factor
Explanation
Cosmids are cloning vectors that were developed to enable large fragments of DNA to be cloned and maintained.
Cosmid vectors allow the cloning of fragments up to 45 kilobases (kb) and are commonly used in genomic library construction.
Cosmid vectors are plasmids with a small region of cos sequence of bacteriophage.
Thus, the correct answer is option C.
The natural function of restriction enzymes is to cut up foreign DNA. Who got the Nobel prize for their experiments on these enzymes?
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W. Arber and H. Smith
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D. Nathans
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Both A and B
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None of the above
Explanation
Restriction endonuclease and its experiments were done by Arber, Smith, and Nathans who all were awarded the Nobel prize in 1978. They performed experiments proving that there are certain enzymes produced by the bacteria which help in the cleavage of the genomes of the pathogens.
So the correct answer is "Both A and B".
Who discovered PCR (polymerase chain reaction)?
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Wilmut
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A. Jeffreys
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Einthoven
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Kary Mullis
Explanation
In 1979, Kary Mullis invented the polymerase chain reaction (PCR), a technique that amplifies specific DNA sequences from very small amounts of genetic material.
The one which has largest genome size
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R
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F
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$${ { \mu }_{ 4 } }$$
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$${ \lambda }$$
Explanation
Genome size is usually measured in base pairs (or bases in single-stranded DNA or RNA). The C-value is another measure of genome size. A special plasmid called a fertility (F) factor plays an important role in conjugation. The F factor contains genes that encourage cellular attachment during conjugation and accelerate plasmid transfer between conjugating bacterial cells. R plasmid or resistance plasmid is a conjugative factor in bacterial cells that promotes resistance to agents such as antibiotics, metal ions, ultraviolet radiation, and bacteriophages. It has the largest genome size of about 117 kb length base pairs. Bacteriophage lambda vectors can complete their life cycles even if foreign DNA was inserted into a portion of its genome. A lambda molecule that is between 78% and 105% of wild-type length can be packaged. This is from 37 to 53 kb in length. The 2-mu plasmid of yeast has a mechanism which allows it to rapidly amplify its copy number without initiating multiple rounds of replication. Thus, the correct answer is option A.
The frequency of recombination is
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Same for all genes
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Highest for genes that first entered the recipient cells
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Lowest for genes that first entered the recipient cells
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None of the above
Explanation
The frequency of recombinants determines the order of entry for each gene. During the process of conjugation, the genes are transferred through the conjugation tube. Spontaneous breakage of this tube creates a natural gradient of transfer. There are fewer chances that the latter genes will be received by the bacterial cell. The gene which enters the first in the cell has the maximum frequency of recombination compared to the other latter genes.
Thus, the correct answer is option B.
Plasmid's replication
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Is autonomous.
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Depends on the genomic DNA.
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Initiator dependent.
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Does not replicate.
Explanation
A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small, circular, double-stranded DNA molecules. Plasmids are considered replicons, a unit of DNA capable of replicating autonomously within a suitable host. Plasmids can be transmitted from one bacterium to another (even of another species) via three main mechanisms transformation, transduction and conjugation. This host-to-host transfer of genetic material is called as horizontal gene transfer.
Therefore, the correct answer is option A.
The most useful plasmid for cloning is
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pBR 323
0%
pTM 223
0%
pBR 222
0%
pBR 322
Explanation
A cloning vector is a small piece of DNA, which carries the desired gene from one cell to another for cloning.
There are many types of cloning vectors, but the most commonly used ones are genetically engineered plasmids.
pBR322 is a plasmid and is one of the first widely used
E. coli
cloning vectors.
It was created in 1977 in the laboratory of Herbert Boyer at the University of California, San Francisco.
Hence, Option D is correct.
This is figure of plasmid pBRThe gene conferring resistance to ampicillin (ApR) can be interrupted by insertion of a DNA fragment into the Pstl site, and the gene conferring resistance to tetracycline (TcR) can be interrupted by insertion of a DNA fragment into the BamHI site. Replication is controlled by the CoIEl origin. Use of the TcR and ApR genes allows for easy screening for recombinants carrying inserts of foreign DNA. For locating Eco RI, TcR and ApR gene on it. Identify, what is represented by A, B and C.
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A- TeR, B- ApR and C- EcoRI
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A- EcoRI, B- ApR and C- TcR
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A- TeR, B- EcoRI and C- ApR
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A- ApR, B- tet R and C- EcoRI
Explanation
pBR322 is a plasmid and was one of the first widely used
E. coli
cloning vectors. pBR322 contains the ampR gene (A), encoding the ampicillin resistance protein and the tetR gene (B), encoding the tetracycline resistance protein and the rop gene, encoding a restrictor of plasmid copy number. Restriction endonucleases EcoRI (C) and HindIII are used to analyze the structure of the plasmid genome responsible for the EcoRI restriction endonuclease and modification methylase.
Therefore, the correct answer is option D.
In genetic engineering, the term vector is applied for
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Plasmids
0%
Source of DNA
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Cell which receives DNA
0%
Active disease causing viruses
0%
All of the above
Explanation
In molecular cloning, 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 containing foreign DNA is termed as recombinant DNA. The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes. Of these, the most commonly used vectors are plasmids. Plasmids may be used specifically as transcription vectors and such plasmids may lack crucial sequences for protein expression. Plasmids used for protein expression, called as expression vectors, would include elements for translation of protein, such as a ribosome binding site, start and stop codons.
Restriction endonuclease cuts DNA at specific sites and cellular DNA is not damaged as
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Rest enzyme susceptible sites are coated with protein
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Rest enzyme susceptible sites are catalyzed by particular enzymes
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They cleave DNA only at very limited and specific sites
0%
All of the above
Explanation
The restriction enzymes used in molecular biology usually recognize short target sequences of about 4 8 base pairs. Restriction enzymes are very specific to their cleavage function. The site which is recognized by this enzyme for cleavage is the restriction site.
Typically, a restriction site will be a palindromic sequence of about four to six nucleotides long where restriction endonuclease makes nick.
Therefore, the correct answer is option C.
The enzyme used in polymerase chain reaction (PCR) is
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Taq polymerase
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RNA polymerase
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Ribonuclease
0%
Endonuclease
Explanation
The key ingredients of polymerase chain reaction are Taq polymerase which is a DNA polymerase enzyme that makes new DNA strand from the isolated DNA. It is isolated from bacterium,
Thermus acquaticus.
Whereas R
NA polymerase is a type of enzyme that produces Primary RNA transcript from the DNA, nuclease enzyme is used to cleave the nucleic acid within the sequence called as endonuclease such as ribonuclease
So, the correct answer is '
Taq polymerase'
Metabolic engineering is the branch of biotechnology for improvement of cellular activities by manipulation of enzymatic, transport and regulatory functions of cells using recombinant DNA technology. Still this science has limitations due to
Report Question
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Difficulty in making industrial strains by DNA recombinant technology.
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Complex interaction of metabolic network.
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Both of (A) and (B).
0%
None of the above.
Explanation
Metabolic engineering is generally referred to as the targeted and purposeful alteration of metabolic pathways found in an organism in order to better understand and utilize cellular pathways for chemical transformation, energy transduction and supramolecular assembly. Microbial catalysts are not as malleable as those in synthetic organic chemistry and metabolic engineers face many difficulties in the development of microbial catalysts: (i) cost and availability of starting materials (e.g., carbon substrates); (ii) metabolic route and corresponding genes encoding the enzymes in the pathway to produce the desired product; (iii) most appropriate microbial host; (iv) robust and responsive genetic control system for the desired pathways and chosen host; (v) methods for debugging and debottle necking the constructed pathway; and (vi) ways to maximize yields, titres, and productivities. The practical applications of biocatalytic chemical conversions are often restricted due to their complexities involving the unpredictability of product yield and the troublesome controls in fermentation processes.
DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by
Report Question
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Polymerase chain reaction
0%
Electrophoresis
0%
Restriction mapping
0%
Centrifugation
Explanation
A restriction enzyme (or restriction endonuclease) is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. The DNA fragments are separated by electrophoresis, a process that involves application of an electric field to cause the DNA fragments to migrate into an agarose gel. The gel is then stained with a methylene blue stain to visualize the DNA bands and may be photographed.
Thus, the correct answer is option B.
PCR and Restriction Fragment Length Polymorphism are the methods used for ?
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DNA sequencing
0%
Genetic fingerprinting
0%
Study of immunology
0%
Genetic transformation
Explanation
PCR and RFLP are the methods used for genetic fingerprinting. DNA fragmentation plays an important part in forensics, especially that of DNA profiling. Restriction fragment length polymorphism (RFLP) analyses the variable lengths of DNA fragments which are formed from the digestion of a DNA sample with a restriction endonuclease. They are then hybridized with DNA probes that bind to a complementary DNA sequence in the sample. In polymerase chain reaction (PCR), This sample DNA is amplified from a single copy to millions of copies of DNA. It used to amplify a specific region of a DNA strand. Most PCR methods amplify DNA fragments of between 0.1 and 10 kilo base pairs (kb), although some techniques allow amplification of fragments up to 40 kb in size.
Plasmids useful in genetic engineering are cut at specific sites by
Report Question
0%
Same enzymes that cut the portion of DNA to be inserted into it
0%
Hot alkaline solution
0%
Any hydrolytic enzymes
0%
Ligase enzyme
Explanation
Plasmids are the vectors that are used for the transfer of genes from the parent cell to the desired cell.
If we cut plasmid DNA and foreign DNA with the same restriction enzyme both will produce fragments with the same complementary sticky ends.
Foreign DNA and a plasmid having complementary ends can be easily ligated using DNA ligase.
So, the correct answer is option A.
Hfr forms of bacteria are those which have
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No F factor
0%
F factor
0%
F factor fused with main chromosome
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None of the above
Explanation
HFr
is a
high-frequency
recombination bacterial cell whose sex plasmid is attached to the main chromosome. They have more affinity for F-ve bacterial cells. When a
bacterium that possesses the F factor integrated into the bacterial genome conjugates with another bacterium, it attempts to transfer a copy of the F factor as well as a portion of or the entire chromosome to the recipient bacterium. Hfr stands for high frequency of recombination, first described by the population geneticist, Luca Cavalli-Sforza.
Bacteria uses restriction endonuclease to protect itself from viral attack. The bacterial DNA does not get degraded by its own enzyme because
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DNA of bacteria is able to reintegrate itself.
0%
Bacterial DNA does not have specific site.
0%
Bacterial DNA protect itself by changing the configuration of active site.
0%
The enzyme cannot identify the sites.
Explanation
Bacteria have restriction endonucleases, which cleave double stranded DNA at specific points. This prevents viral infection of by destroying the viral DNA introduced by a bacteriophage. Therefore, in order to prevent the destruction of its own DNA by the restriction enzymes, bacteria uses modification system where they modify their DNA by adding methyl groups. This modification must not interfere with the DNA base-pairing, and therefore, usually only a few specific bases are modified on each strand.
Thus, the correct answer is option C.
Electroporation involves
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Promotion of seed germination by induced imbibition of water with electric current
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Making transient pores in cell membranes to facilitate entry of gene constructs
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Purification of saline water with the help of an artificial membrane
0%
Passage of sucrose through sieve pores by electro-osmosis
Explanation
Electroporation is a molecular biology technique in which an electrical field is created to create pores in the cell wall of the host cells. This results in the increase in the permeability of the cells and they allow the entry of the chemicals, drugs, or DNA molecules into the cell. This technique can be used to modify the genome of the bacteria, yeast and plant cells.
Thus, the correct answer is option B.
Restriction endonuclease, an enzyme used in genetic engineering is employed for
Report Question
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Probing exons
0%
Cutting double stranded DNA
0%
Cutting single stranded DNA
0%
Joining strands of DNA
0%
Copying DNA strands
Explanation
A restriction enzyme (or restriction endonuclease) is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. To cut DNA, all restriction enzymes make two incisions, once through each sugar-phosphate backbone (i.e., each strand) of the DNA double helix. These enzymes are found in bacteria and archaea and provide a defence mechanism against invading viruses. Inside a prokaryote, the restriction enzymes selectively cut up foreign DNA in a process called as restriction.
Gene recombinant technology is used for
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Vectorless gene transfer into target cell.
0%
Vector based gene transfer into target cell.
0%
Direct transfer of DNA protein complex.
0%
Liposome base direct gene transfer into target cell.
Explanation
In molecular cloning, the DNA molecules are used as the vector to transfer the desired gene into the host cell.
Desired gene gets incorporated into the host genome and then replicates to express the gene.
The vectors are constructed using the recombinant DNA technology method.
Vectors are of different types based on their size and the number of genes they can carry. The most common vectors are the plasmids.
Thus, the correct answer is option B.
In a PCR machine, which of the following is used to produce multiple copies of DNA?
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Agrobacterium
0%
Escherichia coli
0%
Thermus aquaticus
0%
Lactobacillus
Explanation
The thermal cycler is a laboratory apparatus most commonly used to amplify segments of DNA via the polymerase chain reaction (PCR).
It is
also known as a thermocycler, PCR machine or DNA amplifier.
Thermal cyclers may also be used in laboratories to facilitate other temperature-sensitive reactions, including but not limited to restriction enzyme digestion or rapid diagnostics.
Later, the PCR process was adapted to the use of thermostable DNA polymerase enzyme from
Thermus aquaticus
, which greatly simplified the design of the thermal cycler.
So, the correct answer is '
Thermus aquaticus'
Cloning is meant for
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Production of HGH gene in $$E.\, coli$$
0%
To preserve the genotype of organism
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To replace the original gene
0%
All of the above
Explanation
Clone is a population of cells or individuals which are genetically identical. With the death of an organism, a particular genotype is lost. Cloning is meant for preservation of the genotype of an organism. The cloning is of two types namely i.e., gene cloning at molecular level and
cloning of organisms.
Therefore, the correct answer is option B.
Which one is a true statement regarding DNA polymerase used in PCR?
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0%
It is isolated from a virus.
0%
It remains active at high temperature.
0%
It is used to ligate introduced DNA in recipient cells.
0%
It serves as a selectable marker.
Explanation
The primary requirements for a DNA polymerase used in PCR are optimal activity at temperatures around 75$$^o$$C and the ability to retain that activity after prolonged incubation at even higher temperatures (95$$^o$$C). The first thermostable DNA polymerase to be widely used for PCR is Taq DNA Polymerase.
Trigger protein required by cells to pass through restriction point is
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0%
U-protein
0%
R-protein
0%
T-protein
0%
P-protein
Explanation
The restriction point (R) is a point in the G$$_1$$ phase of an animal cell cycle. At this point the cell becomes committed and no extracellular proliferation stimulants are required. The cells require a protein to pass through the restriction point. This protein is known as the trigger point or the T-protein. There should be enough trigger protein to allow the cell to cross the checkpoint.
Thus, the correct answer is option C.
Select the wrong statement from the following.
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0%
Pectinase and cellulase dissolve the cell wall.
0%
Some
Cyanobacteria
form symbiotic association with the fern
Azolla
.
0%
Regeneration of cell wall in somatic hybridisation is induced by PEG.
0%
Plants obtained through pollen culture are always haploids.
0%
Shoot regeneration in callus is promoted by cytokinin like BAP.
0%
None of the above.
Explanation
Pollen culture (microspore culture) is a technique in which haploid plants are obtained from isolated pollen grains. Pollen or microspore culture is an in vitro technique by which the pollen grains, preferably at the uninucleate stage, are squeezed out aseptically from the intact anther and then cultured on nutrient medium where the microscope, without producing male gametes, develop into haploid embryoids or callus tissues that give rise to haploid plantlets by embryogenesis or organogenesis. Polyethylene glycol (PEG)-mediated cell fusion is a simple and efficient technique used widely for the production of somatic cell hybrids and for nuclear transfer in mammalian cloning. Fusion can be performed between adherent and suspension cells or between adherent cells or suspension cells. Cytokinins are the key factor to induce the direct shoot regeneration.
Azolla
form a symbiotic relationship with the cyanobacterium,
Anabaena azollae
, which fixes atmospheric nitrogen, giving the plant access to the essential nutrient. Pectinase is an enzyme that breaks down pectin, a polysaccharide found in plant cell walls. Cellulases contribute to the enzymatic splitting of cellulose, a component of cell wall.
For transformation, micro-particles coated with DNA to be bombarded with biolistic gene gun are made up of?
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0%
Silicon or platinum
0%
Gold or tungsten
0%
Silver or aluminium
0%
Platinum or zinc
Explanation
A gene gun is a system in which a particle is used to inject the genetic material directly into the host's genome. This method is known as biolistic particle delivery system which was originally designed for plant transformation. A metal particle is coated with the genetic material and transferred into the host cells to allow the foreign DNA get incorporated into the hosts' genome.
The particles are generally made up of the inert materials like the gold or tungsten which are inert and does not react with the DNA. The particles are accelerated with force to enter into the cells and then the selectable markers are used to identify the cells that take up the transgene.
Thus, the correct answer is option B.
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Practice Class 12 Medical Biology Quiz Questions and Answers
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