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NEET ]1[ Contd...
NEET Biology Class 12 - Biotechnology: Principles and Processes Ultra-Hard Question Bank
Instructions:
- Each question has four options (1), (2), (3), (4). Choose the most correct answer.
- Each correct answer carries 4 marks.
- Each wrong answer will deduct 1 marks.
- Unanswered questions will not be penalised.
1.Consider the following statements regarding the biographical and scientific milestones of
Herbert Boyer:
I. He completed his graduate work at the University of Pittsburgh in 1963, which was followed
by three years of post-graduate studies at Yale University.
II. In 1966, Boyer took over an assistant professorship at the University of California at San
Francisco.
III. By 1969, he performed studies on a couple of restriction enzymes of the E. coli bacterium
that left what became known as 'sticky ends' on the DNA strands.
IV. Boyer's discovery of restriction enzymes leaving sticky ends made the pasting together of
DNA pieces a highly random and unpredictable exercise.
Which of the statements given above are correct?
Herbert Boyer:
I. He completed his graduate work at the University of Pittsburgh in 1963, which was followed
by three years of post-graduate studies at Yale University.
II. In 1966, Boyer took over an assistant professorship at the University of California at San
Francisco.
III. By 1969, he performed studies on a couple of restriction enzymes of the E. coli bacterium
that left what became known as 'sticky ends' on the DNA strands.
IV. Boyer's discovery of restriction enzymes leaving sticky ends made the pasting together of
DNA pieces a highly random and unpredictable exercise.
Which of the statements given above are correct?
2.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Stanley Cohen developed a method of removing small ringlets of DNA called
plasmids from certain bacterial cells and then reinserting them in other cells.
Reason (R): Plasmids float about freely in the cytoplasm of certain bacterial cells and replicate
independently from the coding strand of DNA.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Stanley Cohen developed a method of removing small ringlets of DNA called
plasmids from certain bacterial cells and then reinserting them in other cells.
Reason (R): Plasmids float about freely in the cytoplasm of certain bacterial cells and replicate
independently from the coding strand of DNA.
In the light of the above statements, choose the correct answer:
3.Consider the following statements regarding the historic collaboration between Herbert
Boyer and Stanley Cohen:
I. Their rich and rewarding conversation occurred in Hawaii, bringing together Boyer's work
on restriction enzymes and Cohen's work on plasmids.
II. Combining plasmid isolation with DNA splicing enabled them to recombine segments of DNA
in desired configurations.
III. They inserted the recombined DNA into bacterial cells, which could then act as
manufacturing plants for specific lipids.
IV. The breakthrough of Boyer and Cohen was the basis upon which the discipline of
biotechnology was founded.
Which of the statements given above are correct?
Boyer and Stanley Cohen:
I. Their rich and rewarding conversation occurred in Hawaii, bringing together Boyer's work
on restriction enzymes and Cohen's work on plasmids.
II. Combining plasmid isolation with DNA splicing enabled them to recombine segments of DNA
in desired configurations.
III. They inserted the recombined DNA into bacterial cells, which could then act as
manufacturing plants for specific lipids.
IV. The breakthrough of Boyer and Cohen was the basis upon which the discipline of
biotechnology was founded.
Which of the statements given above are correct?
4.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Processes like making curd, bread, or wine, which are all microbe-mediated, are
considered forms of biotechnology.
Reason (R): In the modern context, biotechnology is used in a highly restricted sense to refer to
only those processes that use genetically modified organisms to produce products on a larger
scale.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Processes like making curd, bread, or wine, which are all microbe-mediated, are
considered forms of biotechnology.
Reason (R): In the modern context, biotechnology is used in a highly restricted sense to refer to
only those processes that use genetically modified organisms to produce products on a larger
scale.
In the light of the above statements, choose the correct answer:
5.According to the introductory section of Chapter 9, which of the following
techniques/processes are explicitly included as part of biotechnology?
I. In vitro fertilisation leading to a 'test-tube' baby.
II. Synthesising a gene and using it.
III. Developing a DNA vaccine.
IV. Correcting a defective gene.
Choose the correct option:
techniques/processes are explicitly included as part of biotechnology?
I. In vitro fertilisation leading to a 'test-tube' baby.
II. Synthesising a gene and using it.
III. Developing a DNA vaccine.
IV. Correcting a defective gene.
Choose the correct option:
6.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The European Federation of Biotechnology (EFB) has provided a definition of
biotechnology that encompasses only the modern molecular biotechnology view.
Reason (R): The EFB definition is: 'The integration of natural science and organisms, cells,
parts thereof, and molecular analogues for products and services'.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The European Federation of Biotechnology (EFB) has provided a definition of
biotechnology that encompasses only the modern molecular biotechnology view.
Reason (R): The EFB definition is: 'The integration of natural science and organisms, cells,
parts thereof, and molecular analogues for products and services'.
In the light of the above statements, choose the correct answer:
7.Consider the following statements regarding the two core techniques that enabled the birth
of modern biotechnology:
I. Genetic engineering involves techniques to alter the chemistry of genetic material (DNA and
RNA).
II. The ultimate aim of genetic engineering is to introduce altered genetic material into host
organisms and thus change the genotype of the host organism.
III. Bioprocess engineering involves the maintenance of sterile (microbial contamination-free)
ambience in chemical engineering processes.
IV. The sterile ambience in bioprocess engineering enables the growth of only the desired
microbe or eukaryotic cell in large quantities for the manufacture of products like antibiotics,
vaccines, and enzymes.
Which of the statements given above are correct?
of modern biotechnology:
I. Genetic engineering involves techniques to alter the chemistry of genetic material (DNA and
RNA).
II. The ultimate aim of genetic engineering is to introduce altered genetic material into host
organisms and thus change the genotype of the host organism.
III. Bioprocess engineering involves the maintenance of sterile (microbial contamination-free)
ambience in chemical engineering processes.
IV. The sterile ambience in bioprocess engineering enables the growth of only the desired
microbe or eukaryotic cell in large quantities for the manufacture of products like antibiotics,
vaccines, and enzymes.
Which of the statements given above are correct?
8.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Asexual reproduction preserves the genetic information, while sexual
reproduction permits variation.
Reason (R): Sexual reproduction provides opportunities for variations and formulation of
unique combinations of genetic setup, some of which may be beneficial to the organism as well
as the population.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Asexual reproduction preserves the genetic information, while sexual
reproduction permits variation.
Reason (R): Sexual reproduction provides opportunities for variations and formulation of
unique combinations of genetic setup, some of which may be beneficial to the organism as well
as the population.
In the light of the above statements, choose the correct answer:
9.Consider the following statements regarding the breeding methods used in agriculture and
animal husbandry:
I. Traditional hybridisation procedures very often lead to the inclusion and multiplication of
undesirable genes along with the desired genes.
II. Traditional hybridisation procedures are highly specific and always introduce only the
desired gene into the target organism.
III. The techniques of genetic engineering include the creation of recombinant DNA, use of gene
cloning, and gene transfer.
IV. Genetic engineering overcomes the limitations of traditional hybridisation by allowing us to
isolate and introduce only one or a set of desirable genes without introducing undesirable genes.
Which of the statements given above are correct?
animal husbandry:
I. Traditional hybridisation procedures very often lead to the inclusion and multiplication of
undesirable genes along with the desired genes.
II. Traditional hybridisation procedures are highly specific and always introduce only the
desired gene into the target organism.
III. The techniques of genetic engineering include the creation of recombinant DNA, use of gene
cloning, and gene transfer.
IV. Genetic engineering overcomes the limitations of traditional hybridisation by allowing us to
isolate and introduce only one or a set of desirable genes without introducing undesirable genes.
Which of the statements given above are correct?
10.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): An alien piece of DNA transferred into an host organism has to become part of a
chromosome to multiply and be inherited along with the host DNA.
Reason (R): A chromosome contains a specific DNA sequence called the origin of replication,
which is responsible for initiating replication.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): An alien piece of DNA transferred into an host organism has to become part of a
chromosome to multiply and be inherited along with the host DNA.
Reason (R): A chromosome contains a specific DNA sequence called the origin of replication,
which is responsible for initiating replication.
In the light of the above statements, choose the correct answer:
11.Consider the following statements regarding the molecular events of DNA replication and
cloning:
I. An alien DNA must be linked with the origin of replication to replicate and multiply itself in
the host organism.
II. Cloning is defined as the process of making multiple identical copies of any template DNA.
III. The likely fate of any unlinked piece of alien DNA transferred into an host organism is that
it will rapidly multiply and integrate itself automatically.
Which of the statements given above is/are correct?
cloning:
I. An alien DNA must be linked with the origin of replication to replicate and multiply itself in
the host organism.
II. Cloning is defined as the process of making multiple identical copies of any template DNA.
III. The likely fate of any unlinked piece of alien DNA transferred into an host organism is that
it will rapidly multiply and integrate itself automatically.
Which of the statements given above is/are correct?
12.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The construction of the first artificial recombinant DNA molecule was
accomplished by Stanley Cohen and Herbert Boyer in the year 1972.
Reason (R): They isolated the antibiotic resistance gene by cutting out a piece of DNA from a
native plasmid of Salmonella typhimurium.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The construction of the first artificial recombinant DNA molecule was
accomplished by Stanley Cohen and Herbert Boyer in the year 1972.
Reason (R): They isolated the antibiotic resistance gene by cutting out a piece of DNA from a
native plasmid of Salmonella typhimurium.
In the light of the above statements, choose the correct answer:
13.Consider the following statements regarding the role of plasmid vectors in recombinant
DNA technology:
I. A native plasmid of Salmonella typhimurium is an autonomously replicating circular extra-
chromosomal DNA.
II. Plasmids act as vectors to transfer pieces of DNA attached to them into host organisms.
III. The NCERT textbook compares the role of a plasmid vector to a mosquito, which acts as an
insect vector to transfer the malarial parasite into the human body.
IV. The insect vector used to transfer the malarial parasite is explicitly described in the text as
the female Anopheles mosquito.
Which of the statements given above are correct?
DNA technology:
I. A native plasmid of Salmonella typhimurium is an autonomously replicating circular extra-
chromosomal DNA.
II. Plasmids act as vectors to transfer pieces of DNA attached to them into host organisms.
III. The NCERT textbook compares the role of a plasmid vector to a mosquito, which acts as an
insect vector to transfer the malarial parasite into the human body.
IV. The insect vector used to transfer the malarial parasite is explicitly described in the text as
the female Anopheles mosquito.
Which of the statements given above are correct?
14.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The linking of the antibiotic resistance gene with the plasmid vector in vitro
became possible with the discovery of the enzyme DNA ligase.
Reason (R): DNA ligase acts on cut DNA molecules and joins their ends by catalyzing the
synthesis of phosphodiester bonds between adjacent nucleotides.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The linking of the antibiotic resistance gene with the plasmid vector in vitro
became possible with the discovery of the enzyme DNA ligase.
Reason (R): DNA ligase acts on cut DNA molecules and joins their ends by catalyzing the
synthesis of phosphodiester bonds between adjacent nucleotides.
In the light of the above statements, choose the correct answer:
15.Consider the following statements regarding the transfer and replication of the first
artificial recombinant DNA molecule:
I. The newly created circular autonomously replicating DNA created in vitro is known as
recombinant DNA.
II. The recombinant DNA was transferred into Escherichia coli, which is a bacterium closely
related to Salmonella.
III. The transferred DNA replicated in the host cell using E. coli's native DNA polymerase
enzyme.
IV. The multiplication of copies of the antibiotic resistance gene in E. coli was called the cloning
of the antibiotic resistance gene in E. coli.
Which of the statements given above are correct?
artificial recombinant DNA molecule:
I. The newly created circular autonomously replicating DNA created in vitro is known as
recombinant DNA.
II. The recombinant DNA was transferred into Escherichia coli, which is a bacterium closely
related to Salmonella.
III. The transferred DNA replicated in the host cell using E. coli's native DNA polymerase
enzyme.
IV. The multiplication of copies of the antibiotic resistance gene in E. coli was called the cloning
of the antibiotic resistance gene in E. coli.
Which of the statements given above are correct?
16.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): One of the basic steps in genetically modifying an organism is the introduction of
identified DNA with desirable genes into the host.
Reason (R): Once introduced, the identified DNA must be maintained in the host and
transferred to its progeny during cell division.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): One of the basic steps in genetically modifying an organism is the introduction of
identified DNA with desirable genes into the host.
Reason (R): Once introduced, the identified DNA must be maintained in the host and
transferred to its progeny during cell division.
In the light of the above statements, choose the correct answer:
17.According to Section 9.1, which of the following represents the correct, sequentially
ordered list of the three basic steps in genetically modifying an organism?
I. Identification of DNA with desirable genes.
II. Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
III. Introduction of the identified DNA into the host.
Choose the correct sequence from the options below:
ordered list of the three basic steps in genetically modifying an organism?
I. Identification of DNA with desirable genes.
II. Maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
III. Introduction of the identified DNA into the host.
Choose the correct sequence from the options below:
18.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Recombinant DNA technology can be accomplished only if we have key tools like
restriction enzymes, polymerase enzymes, ligases, vectors, and the host organism.
Reason (R): The host organism is required specifically to synthesize molecular scissors in vivo to
cut the vector DNA at high-efficiency sites.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Recombinant DNA technology can be accomplished only if we have key tools like
restriction enzymes, polymerase enzymes, ligases, vectors, and the host organism.
Reason (R): The host organism is required specifically to synthesize molecular scissors in vivo to
cut the vector DNA at high-efficiency sites.
In the light of the above statements, choose the correct answer:
19.Consider the following statements regarding the historic isolation of E. coli enzymes in the
year 1963:
I. In 1963, two enzymes responsible for restricting the growth of bacteriophage in Escherichia
coli were isolated.
II. One of the isolated enzymes added methyl groups to the viral capsid protein, while the other
cut the viral DNA.
III. The enzyme that cut the DNA was subsequently named restriction endonuclease.
Which of the statements given above is/are correct?
year 1963:
I. In 1963, two enzymes responsible for restricting the growth of bacteriophage in Escherichia
coli were isolated.
II. One of the isolated enzymes added methyl groups to the viral capsid protein, while the other
cut the viral DNA.
III. The enzyme that cut the DNA was subsequently named restriction endonuclease.
Which of the statements given above is/are correct?
20.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The functioning of Hind II, the first restriction endonuclease, was found to
depend on a specific DNA nucleotide sequence.
Reason (R): Hind II was isolated and characterized exactly five years after the initial 1963
enzyme isolation experiments.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The functioning of Hind II, the first restriction endonuclease, was found to
depend on a specific DNA nucleotide sequence.
Reason (R): Hind II was isolated and characterized exactly five years after the initial 1963
enzyme isolation experiments.
In the light of the above statements, choose the correct answer:
21.Consider the following statements regarding the molecular properties of Hind II:
I. Hind II always cuts DNA molecules at a particular point by recognizing a specific sequence of
six base pairs.
II. This specific base sequence is known as the recognition sequence for Hind II.
III. The sequence recognized by Hind II is a highly variable sequence consisting of a range of
four to eight base pairs depending on salt concentration.
Which of the statements given above are correct?
I. Hind II always cuts DNA molecules at a particular point by recognizing a specific sequence of
six base pairs.
II. This specific base sequence is known as the recognition sequence for Hind II.
III. The sequence recognized by Hind II is a highly variable sequence consisting of a range of
four to eight base pairs depending on salt concentration.
Which of the statements given above are correct?
22.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Today we know of more than 900 restriction enzymes that have been isolated
from over 230 strains of bacteria.
Reason (R): Each of these 900+ restriction enzymes recognizes different recognition sequences
within target DNA molecules.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Today we know of more than 900 restriction enzymes that have been isolated
from over 230 strains of bacteria.
Reason (R): Each of these 900+ restriction enzymes recognizes different recognition sequences
within target DNA molecules.
In the light of the above statements, choose the correct answer:
23.Consider the following statements regarding the naming convention of restriction
endonucleases using EcoRI as an example:
I. The first letter of the name comes from the genus of the prokaryotic cell from which the
enzyme was isolated.
II. The second two letters come from the species of the prokaryotic cell.
III. In EcoRI, the letter 'R' is derived from the name of the researcher who discovered the
strain.
IV. The Roman numbers following the names indicate the order in which the enzymes were
isolated from that strain of bacteria.
Which of the statements given above are correct?
endonucleases using EcoRI as an example:
I. The first letter of the name comes from the genus of the prokaryotic cell from which the
enzyme was isolated.
II. The second two letters come from the species of the prokaryotic cell.
III. In EcoRI, the letter 'R' is derived from the name of the researcher who discovered the
strain.
IV. The Roman numbers following the names indicate the order in which the enzymes were
isolated from that strain of bacteria.
Which of the statements given above are correct?
24.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The restriction endonuclease EcoRI is isolated from Escherichia coli RY 13.
Reason (R): In EcoRI, the letters 'co' come from the species 'coli' of the bacterium, and 'I'
indicates that it is the first enzyme isolated from this strain.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The restriction endonuclease EcoRI is isolated from Escherichia coli RY 13.
Reason (R): In EcoRI, the letters 'co' come from the species 'coli' of the bacterium, and 'I'
indicates that it is the first enzyme isolated from this strain.
In the light of the above statements, choose the correct answer:
25.Consider the following statements regarding the two major kinds of nucleases:
I. Restriction enzymes belong to a larger class of enzymes called nucleases.
II. Exonucleases make cuts at specific positions within the DNA.
III. Endonucleases remove nucleotides from the ends of the DNA.
Which of the statements given above is/are correct?
I. Restriction enzymes belong to a larger class of enzymes called nucleases.
II. Exonucleases make cuts at specific positions within the DNA.
III. Endonucleases remove nucleotides from the ends of the DNA.
Which of the statements given above is/are correct?
26.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Each restriction endonuclease functions by 'inspecting' the length of a DNA
sequence.
Reason (R): Once it finds its specific recognition sequence, it binds to the DNA and cuts only one
strand of the double helix at specific points in the sugar-phosphate backbone.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Each restriction endonuclease functions by 'inspecting' the length of a DNA
sequence.
Reason (R): Once it finds its specific recognition sequence, it binds to the DNA and cuts only one
strand of the double helix at specific points in the sugar-phosphate backbone.
In the light of the above statements, choose the correct answer:
27.Consider the following statements regarding the palindromic sequences recognized by
restriction endonucleases:
I. Each restriction endonuclease recognizes a specific palindromic nucleotide sequence in the
DNA.
II. A DNA palindrome is a sequence of base pairs that reads the same on the two strands when
the orientation of reading is kept the same.
III. The orientation of reading must be kept opposite on the two strands (e.g., 5′ 3′ on one and
3′ 5′ on the other) to find the same sequence.
IV. The sequence 5′-GAATTC-3′ reads the same as 3′-CTTAAG-5′ when both are read in the 5′ 3′ direction.
Which of the statements given above are correct?
restriction endonucleases:
I. Each restriction endonuclease recognizes a specific palindromic nucleotide sequence in the
DNA.
II. A DNA palindrome is a sequence of base pairs that reads the same on the two strands when
the orientation of reading is kept the same.
III. The orientation of reading must be kept opposite on the two strands (e.g., 5′ 3′ on one and
3′ 5′ on the other) to find the same sequence.
IV. The sequence 5′-GAATTC-3′ reads the same as 3′-CTTAAG-5′ when both are read in the 5′ 3′ direction.
Which of the statements given above are correct?
28.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The group of letters 'MALAYALAM' represents a word-palindrome because it
forms the same word when read both forward and backward.
Reason (R): A DNA palindrome is characterized by having complementary bases that read
identically when read in opposite directions on the same strand.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The group of letters 'MALAYALAM' represents a word-palindrome because it
forms the same word when read both forward and backward.
Reason (R): A DNA palindrome is characterized by having complementary bases that read
identically when read in opposite directions on the same strand.
In the light of the above statements, choose the correct answer:
29.Consider the following statements regarding the mechanical details of restriction
endonuclease cleavage:
I. Restriction enzymes cut the strand of DNA exactly in the center of the palindrome sites.
II. Cleavage occurs between the same two bases on the opposite strands of the double helix.
III. The cleavage leaves single-stranded portions at the ends, forming overhanging stretches
called sticky ends.
Which of the statements given above are correct?
endonuclease cleavage:
I. Restriction enzymes cut the strand of DNA exactly in the center of the palindrome sites.
II. Cleavage occurs between the same two bases on the opposite strands of the double helix.
III. The cleavage leaves single-stranded portions at the ends, forming overhanging stretches
called sticky ends.
Which of the statements given above are correct?
30.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Overhanging single-stranded stretches are named 'sticky ends' because they form
hydrogen bonds with their complementary cut counterparts.
Reason (R): The natural stickiness of these overhanging ends significantly facilitates the action
of the enzyme DNA ligase.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Overhanging single-stranded stretches are named 'sticky ends' because they form
hydrogen bonds with their complementary cut counterparts.
Reason (R): The natural stickiness of these overhanging ends significantly facilitates the action
of the enzyme DNA ligase.
In the light of the above statements, choose the correct answer:
31.Consider the following statements regarding the molecular events surrounding the
discovery of restriction enzymes:
I. The two enzymes isolated in 1963 worked together to prevent the replication of
bacteriophages in E. coli host cells.
II. One of the isolated enzymes added methyl groups to host DNA to protect it from host-
mediated self-digestion.
III. The second isolated enzyme cleaved the bacteriophage DNA to restrict its growth.
IV. The cleavage reaction performed by the second enzyme is described in NCERT as taking
place at specific, sequence-defined coordinates inside E. coli.
Which of the statements given above are correct?
discovery of restriction enzymes:
I. The two enzymes isolated in 1963 worked together to prevent the replication of
bacteriophages in E. coli host cells.
II. One of the isolated enzymes added methyl groups to host DNA to protect it from host-
mediated self-digestion.
III. The second isolated enzyme cleaved the bacteriophage DNA to restrict its growth.
IV. The cleavage reaction performed by the second enzyme is described in NCERT as taking
place at specific, sequence-defined coordinates inside E. coli.
Which of the statements given above are correct?
32.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Hind II always cuts DNA molecules at a highly specific point by recognizing a
unique base sequence of six base pairs.
Reason (R): Today we know of more than 900 restriction enzymes each of which recognizes
different recognition sequences.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Hind II always cuts DNA molecules at a highly specific point by recognizing a
unique base sequence of six base pairs.
Reason (R): Today we know of more than 900 restriction enzymes each of which recognizes
different recognition sequences.
In the light of the above statements, choose the correct answer:
33.Consider the following statements regarding the quantitative distribution and strains of
restriction enzymes:
I. More than 900 restriction enzymes have been isolated so far by geneticists.
II. These 900+ enzymes have been isolated from exactly 230 strains of bacteria.
III. Each bacterial strain yields only one specific restriction enzyme.
IV. The Roman numbers following the names of restriction enzymes indicate the order in which
the enzymes were isolated from that strain of bacteria.
Which of the statements given above are correct?
restriction enzymes:
I. More than 900 restriction enzymes have been isolated so far by geneticists.
II. These 900+ enzymes have been isolated from exactly 230 strains of bacteria.
III. Each bacterial strain yields only one specific restriction enzyme.
IV. The Roman numbers following the names of restriction enzymes indicate the order in which
the enzymes were isolated from that strain of bacteria.
Which of the statements given above are correct?
34.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): In the naming convention of restriction enzymes, the first letter comes from the
genus and the next two letters come from the species of the host cell.
Reason (R): The restriction endonuclease EcoRI is isolated from the bacterium Escherichia coli
RY 13.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): In the naming convention of restriction enzymes, the first letter comes from the
genus and the next two letters come from the species of the host cell.
Reason (R): The restriction endonuclease EcoRI is isolated from the bacterium Escherichia coli
RY 13.
In the light of the above statements, choose the correct answer:
35.Consider the following statements regarding the structural components of the name
'EcoRI':
I. The letter 'E' represents the genus Escherichia, and 'co' represents the species coli.
II. The letter 'R' is derived from the first letter of the name of the researcher who first isolated
the strain.
III. The Roman numeral 'I' indicates that it was the first enzyme isolated from Escherichia coli
RY 13.
Which of the statements given above are correct?
'EcoRI':
I. The letter 'E' represents the genus Escherichia, and 'co' represents the species coli.
II. The letter 'R' is derived from the first letter of the name of the researcher who first isolated
the strain.
III. The Roman numeral 'I' indicates that it was the first enzyme isolated from Escherichia coli
RY 13.
Which of the statements given above are correct?
36.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Exonucleases and endonucleases represent the two major kinds of nucleases to
which restriction enzymes belong.
Reason (R): Exonucleases remove nucleotides from the middle of the DNA sequence, whereas
endonucleases make cuts only at the absolute ends of the DNA.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Exonucleases and endonucleases represent the two major kinds of nucleases to
which restriction enzymes belong.
Reason (R): Exonucleases remove nucleotides from the middle of the DNA sequence, whereas
endonucleases make cuts only at the absolute ends of the DNA.
In the light of the above statements, choose the correct answer:
37.Consider the following statements regarding the binding and cleavage mechanism of
restriction endonucleases:
I. Each restriction endonuclease functions by 'inspecting' the length of a DNA sequence.
II. Once it finds its specific recognition sequence, it binds to the DNA molecule.
III. It cuts each of the two strands of the double helix at specific points in their nitrogenous base
backbones.
Which of the statements given above are correct?
Choose the correct option:
restriction endonucleases:
I. Each restriction endonuclease functions by 'inspecting' the length of a DNA sequence.
II. Once it finds its specific recognition sequence, it binds to the DNA molecule.
III. It cuts each of the two strands of the double helix at specific points in their nitrogenous base
backbones.
Which of the statements given above are correct?
Choose the correct option:
38.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Palindromic nucleotide sequences in DNA are highly specific recognition
sequences that read the same on the two strands when orientation is kept the same.
Reason (R): Word-palindromes like 'MALAYALAM' form the same word when read in both
forward and backward directions.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Palindromic nucleotide sequences in DNA are highly specific recognition
sequences that read the same on the two strands when orientation is kept the same.
Reason (R): Word-palindromes like 'MALAYALAM' form the same word when read in both
forward and backward directions.
In the light of the above statements, choose the correct answer:
39.Consider the following statements regarding the palindromic sequences read in 5′ 3′ and
3′ 5′ directions:
I. In a DNA palindrome, the sequence on one strand read in the 5′ 3′ direction matches the
sequence on the complementary strand read in the 3′ 5′ direction.
II. The sequence 5′-GAATTC-3′ on one strand has the complementary sequence 3′-CTTAAG-5′
on the opposite strand.
III. The sequence 5′-GAATTC-3′ reads the same on both strands when read in the 5′ 3′
direction.
IV. The sequence 5′-GAATTC-3′ is the recognition sequence specifically cleaved by Hind II.
Which of the statements given above are correct?
3′ 5′ directions:
I. In a DNA palindrome, the sequence on one strand read in the 5′ 3′ direction matches the
sequence on the complementary strand read in the 3′ 5′ direction.
II. The sequence 5′-GAATTC-3′ on one strand has the complementary sequence 3′-CTTAAG-5′
on the opposite strand.
III. The sequence 5′-GAATTC-3′ reads the same on both strands when read in the 5′ 3′
direction.
IV. The sequence 5′-GAATTC-3′ is the recognition sequence specifically cleaved by Hind II.
Which of the statements given above are correct?
40.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Restriction endonucleases cut the strands of DNA a little away from the center of
the palindrome sites.
Reason (R): The cuts are made between completely different base pairs on the opposite strands
to ensure that the resultant ends are non-complementary.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Restriction endonucleases cut the strands of DNA a little away from the center of
the palindrome sites.
Reason (R): The cuts are made between completely different base pairs on the opposite strands
to ensure that the resultant ends are non-complementary.
In the light of the above statements, choose the correct answer:
41.Consider the following statements regarding the cleavage of the GAATTC palindromic
sequence by the restriction enzyme EcoRI as shown in Figure 9.1:
I. EcoRI binds to the DNA and cuts the sugar-phosphate backbone specifically between G and A
bases on both strands.
II. The cleavage leaves overhanging single-stranded stretches of sequence 5′-AATT-3′ on both
cut DNA fragments.
III. The complementary sticky ends form hydrogen bonds with each other automatically under
appropriate conditions.
IV. The joining of these sticky ends is catalyzed by the enzyme DNA polymerase in the presence
of ATP.
Which of the statements given above are correct?
sequence by the restriction enzyme EcoRI as shown in Figure 9.1:
I. EcoRI binds to the DNA and cuts the sugar-phosphate backbone specifically between G and A
bases on both strands.
II. The cleavage leaves overhanging single-stranded stretches of sequence 5′-AATT-3′ on both
cut DNA fragments.
III. The complementary sticky ends form hydrogen bonds with each other automatically under
appropriate conditions.
IV. The joining of these sticky ends is catalyzed by the enzyme DNA polymerase in the presence
of ATP.
Which of the statements given above are correct?
42.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Recombinant DNA molecules are composed of DNA fragments derived from
entirely different sources or genomes.
Reason (R): Unless one cuts the vector and the source DNA with the same restriction enzyme,
the recombinant vector molecule cannot be created.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Recombinant DNA molecules are composed of DNA fragments derived from
entirely different sources or genomes.
Reason (R): Unless one cuts the vector and the source DNA with the same restriction enzyme,
the recombinant vector molecule cannot be created.
In the light of the above statements, choose the correct answer:
43.Consider the following statements regarding the technical requirements of restriction
enzyme digestion for constructing recombinant plasmids:
I. Normally, one must cut the vector and the source DNA with the same restriction enzyme to
create a recombinant vector.
II. If different restriction enzymes are used, the resultant sticky ends will automatically undergo
non-specific cross-ligation at high efficiency.
III. The sticky ends produced by the same restriction enzyme can be joined together end-to-end
using DNA ligase.
Which of the statements given above is/are correct?
enzyme digestion for constructing recombinant plasmids:
I. Normally, one must cut the vector and the source DNA with the same restriction enzyme to
create a recombinant vector.
II. If different restriction enzymes are used, the resultant sticky ends will automatically undergo
non-specific cross-ligation at high efficiency.
III. The sticky ends produced by the same restriction enzyme can be joined together end-to-end
using DNA ligase.
Which of the statements given above is/are correct?
44.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): DNA fragments generated by restriction endonuclease digestion can be separated
using a technique known as gel electrophoresis.
Reason (R): DNA fragments are negatively charged molecules, and therefore they can be forced
to migrate towards the positive electrode (anode) under an electric field.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): DNA fragments generated by restriction endonuclease digestion can be separated
using a technique known as gel electrophoresis.
Reason (R): DNA fragments are negatively charged molecules, and therefore they can be forced
to migrate towards the positive electrode (anode) under an electric field.
In the light of the above statements, choose the correct answer:
45.Consider the following statements regarding the matrix and resolution properties of
agarose gel electrophoresis:
I. The most commonly used matrix today is agarose, which is a natural polymer extracted from
sea weeds.
II. DNA fragments separate (resolve) according to their size through the chemical binding effect
provided by the agarose matrix.
III. The smaller the fragment size, the farther and faster it moves through the gel matrix.
Which of the statements given above are correct?
agarose gel electrophoresis:
I. The most commonly used matrix today is agarose, which is a natural polymer extracted from
sea weeds.
II. DNA fragments separate (resolve) according to their size through the chemical binding effect
provided by the agarose matrix.
III. The smaller the fragment size, the farther and faster it moves through the gel matrix.
Which of the statements given above are correct?
46.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Pure DNA fragments resolved on an agarose gel are completely invisible under
normal visible light and without staining.
Reason (R): To visualize separated DNA bands, the gel must be stained with a compound named
ethidium bromide followed by exposure to UV radiation.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Pure DNA fragments resolved on an agarose gel are completely invisible under
normal visible light and without staining.
Reason (R): To visualize separated DNA bands, the gel must be stained with a compound named
ethidium bromide followed by exposure to UV radiation.
In the light of the above statements, choose the correct answer:
47.Consider the following statements regarding the visualization and purification of DNA
bands from agarose gels:
I. Stained DNA bands exposed to UV light appear as bright orange coloured bands.
II. Stained DNA bands exposed to UV light appear as bright blue coloured bands in a dark
background.
III. The separated bands of DNA are cut out from the agarose gel and extracted from the gel
piece in a step known as elution.
IV. The purified DNA fragments extracted via elution are directly used in constructing
recombinant DNA by joining them with cloning vectors.
Which of the statements given above are correct?
bands from agarose gels:
I. Stained DNA bands exposed to UV light appear as bright orange coloured bands.
II. Stained DNA bands exposed to UV light appear as bright blue coloured bands in a dark
background.
III. The separated bands of DNA are cut out from the agarose gel and extracted from the gel
piece in a step known as elution.
IV. The purified DNA fragments extracted via elution are directly used in constructing
recombinant DNA by joining them with cloning vectors.
Which of the statements given above are correct?
48.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Plasmids and bacteriophages have the unique ability to replicate within bacterial
cells independent of the control of chromosomal DNA.
Reason (R): Bacteriophages, because of their high number per cell, generally have very high
copy numbers of their genome within the host bacterial cells.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Plasmids and bacteriophages have the unique ability to replicate within bacterial
cells independent of the control of chromosomal DNA.
Reason (R): Bacteriophages, because of their high number per cell, generally have very high
copy numbers of their genome within the host bacterial cells.
In the light of the above statements, choose the correct answer:
49.Consider the following statements regarding the genome copy numbers of plasmids in host
bacterial cells:
I. Some plasmids may have only one or two copies per bacterial cell.
II. Other plasmids may have copy numbers ranging from 15 to 100 per cell, and their numbers
can go even higher.
III. If we link an alien piece of DNA with a vector, we can multiply its numbers equal to the copy
number of the vector.
IV. Current engineered cloning vectors are designed specifically to minimize copy numbers to
prevent host cell lysis.
Which of the statements given above are correct?
bacterial cells:
I. Some plasmids may have only one or two copies per bacterial cell.
II. Other plasmids may have copy numbers ranging from 15 to 100 per cell, and their numbers
can go even higher.
III. If we link an alien piece of DNA with a vector, we can multiply its numbers equal to the copy
number of the vector.
IV. Current engineered cloning vectors are designed specifically to minimize copy numbers to
prevent host cell lysis.
Which of the statements given above are correct?
50.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): If one wants to recover a very large number of copies of the target DNA, it should
be cloned in a vector whose origin of replication (ori) supports high copy numbers.
Reason (R): The origin of replication is a specific sequence in a vector from where replication
starts and is also responsible for controlling the copy number of the linked DNA.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): If one wants to recover a very large number of copies of the target DNA, it should
be cloned in a vector whose origin of replication (ori) supports high copy numbers.
Reason (R): The origin of replication is a specific sequence in a vector from where replication
starts and is also responsible for controlling the copy number of the linked DNA.
In the light of the above statements, choose the correct answer:
51.Consider the following statements regarding the role of selectable markers and
transformation in E. coli:
I. In addition to 'ori', a cloning vector requires a selectable marker to identify and permit non-
transformants while eliminating transformants.
II. Transformation is a procedure through which a piece of DNA is introduced into a host
bacterium.
III. The genes encoding resistance to antibiotics like ampicillin, chloramphenicol, tetracycline,
or kanamycin are considered useful selectable markers for E. coli.
IV. Normal, wild-type E. coli cells naturally carry resistance against all of these common
antibiotics.
Which of the statements given above are correct?
transformation in E. coli:
I. In addition to 'ori', a cloning vector requires a selectable marker to identify and permit non-
transformants while eliminating transformants.
II. Transformation is a procedure through which a piece of DNA is introduced into a host
bacterium.
III. The genes encoding resistance to antibiotics like ampicillin, chloramphenicol, tetracycline,
or kanamycin are considered useful selectable markers for E. coli.
IV. Normal, wild-type E. coli cells naturally carry resistance against all of these common
antibiotics.
Which of the statements given above are correct?
52.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Genes encoding resistance to ampicillin, chloramphenicol, tetracycline, or
kanamycin are considered highly useful selectable markers for cloning in E. coli.
Reason (R): Normal, non-transformed Escherichia coli cells do not naturally carry resistance
against any of these four specific antibiotics.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Genes encoding resistance to ampicillin, chloramphenicol, tetracycline, or
kanamycin are considered highly useful selectable markers for cloning in E. coli.
Reason (R): Normal, non-transformed Escherichia coli cells do not naturally carry resistance
against any of these four specific antibiotics.
In the light of the above statements, choose the correct answer:
53.Consider the following statements regarding the number of recognition sites in cloning
vectors:
I. In order to link alien DNA, a vector needs to have very few, preferably single, recognition sites
for commonly used restriction enzymes.
II. Presence of more than one recognition site within the vector will generate several fragments,
which will significantly complicate gene cloning.
III. Modern vectors are engineered with multiple recognition sites for the same restriction
enzyme clustered together to maximize cleavage efficiency.
Which of the statements given above are correct?
vectors:
I. In order to link alien DNA, a vector needs to have very few, preferably single, recognition sites
for commonly used restriction enzymes.
II. Presence of more than one recognition site within the vector will generate several fragments,
which will significantly complicate gene cloning.
III. Modern vectors are engineered with multiple recognition sites for the same restriction
enzyme clustered together to maximize cleavage efficiency.
Which of the statements given above are correct?
54.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The E. coli cloning vector pBR322 contains two antibiotic resistance genes, ampR
and tetR, which represent useful selectable markers.
Reason (R): The plasmid contains single restriction sites for Hind III, EcoR I, BamH I, Sal I,
Pvu II, Pst I, and Cla I, which are all located exclusively within the ampR gene region.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The E. coli cloning vector pBR322 contains two antibiotic resistance genes, ampR
and tetR, which represent useful selectable markers.
Reason (R): The plasmid contains single restriction sites for Hind III, EcoR I, BamH I, Sal I,
Pvu II, Pst I, and Cla I, which are all located exclusively within the ampR gene region.
In the light of the above statements, choose the correct answer:
55.Consider the following statements regarding the molecular cloning strategy using pBR322
as shown in the text:
I. Ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic
resistance genes.
II. For example, a foreign DNA can be ligated at the BamH I site of the ampicillin resistance
gene in pBR322.
III. The recombinant plasmids will lose tetracycline resistance due to the insertion of foreign
DNA at the BamH I site.
IV. Recombinants can still be selected from non-recombinants by plating on ampicillin-
containing medium.
Which of the statements given above are correct?
as shown in the text:
I. Ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic
resistance genes.
II. For example, a foreign DNA can be ligated at the BamH I site of the ampicillin resistance
gene in pBR322.
III. The recombinant plasmids will lose tetracycline resistance due to the insertion of foreign
DNA at the BamH I site.
IV. Recombinants can still be selected from non-recombinants by plating on ampicillin-
containing medium.
Which of the statements given above are correct?
56.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): E. coli transformants containing pBR322 recombinant plasmids (ligated at
BamHI) will grow on ampicillin-containing medium but fail to grow on tetracycline-containing
medium.
Reason (R): Splicing of foreign DNA into the BamH I restriction site of pBR322 causes the
insertional inactivation of the tetracycline resistance gene.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): E. coli transformants containing pBR322 recombinant plasmids (ligated at
BamHI) will grow on ampicillin-containing medium but fail to grow on tetracycline-containing
medium.
Reason (R): Splicing of foreign DNA into the BamH I restriction site of pBR322 causes the
insertional inactivation of the tetracycline resistance gene.
In the light of the above statements, choose the correct answer:
57.Consider the following statements regarding the selection steps for pBR322 recombinants
ligated at the BamHI site:
I. Transformants are first plated on a medium containing ampicillin to select plasmid-carrying
cells.
II. The colonies growing on the ampicillin medium are then transferred to a medium containing
tetracycline.
III. Recombinants will grow on the tetracycline medium, whereas non-recombinants will grow
only on the ampicillin medium.
IV. Non-recombinants will grow on the medium containing both ampicillin and tetracycline.
Which of the statements given above are correct?
ligated at the BamHI site:
I. Transformants are first plated on a medium containing ampicillin to select plasmid-carrying
cells.
II. The colonies growing on the ampicillin medium are then transferred to a medium containing
tetracycline.
III. Recombinants will grow on the tetracycline medium, whereas non-recombinants will grow
only on the ampicillin medium.
IV. Non-recombinants will grow on the medium containing both ampicillin and tetracycline.
Which of the statements given above are correct?
58.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The 'rop' region in the E. coli cloning vector pBR322 codes for proteins that are
involved in the replication of the plasmid.
Reason (R): Deletion or inactivation of the rop gene leads to the absolute arrest of plasmid
translation and host cell death.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The 'rop' region in the E. coli cloning vector pBR322 codes for proteins that are
involved in the replication of the plasmid.
Reason (R): Deletion or inactivation of the rop gene leads to the absolute arrest of plasmid
translation and host cell death.
In the light of the above statements, choose the correct answer:
59.Consider the following statements regarding the selection of recombinants based on
antibiotic inactivation:
I. Selecting recombinants via antibiotic inactivation is a highly simple, rapid, and single-step
procedure.
II. This procedure is described in NCERT as cumbersome because it requires simultaneous
plating on two plates having different antibiotics.
III. The limitations of antibiotic selection led to the development of alternative selectable
markers that differentiate cells on the basis of colour production.
Which of the statements given above are correct?
antibiotic inactivation:
I. Selecting recombinants via antibiotic inactivation is a highly simple, rapid, and single-step
procedure.
II. This procedure is described in NCERT as cumbersome because it requires simultaneous
plating on two plates having different antibiotics.
III. The limitations of antibiotic selection led to the development of alternative selectable
markers that differentiate cells on the basis of colour production.
Which of the statements given above are correct?
60.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Alternative selectable markers differentiate recombinants from non-
recombinants based on their ability to produce colour in the presence of a chromogenic
substrate.
Reason (R): In these markers, a recombinant DNA is inserted within the coding sequence of the
enzyme beta-galactosidase, leading to its inactivation.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Alternative selectable markers differentiate recombinants from non-
recombinants based on their ability to produce colour in the presence of a chromogenic
substrate.
Reason (R): In these markers, a recombinant DNA is inserted within the coding sequence of the
enzyme beta-galactosidase, leading to its inactivation.
In the light of the above statements, choose the correct answer:
61.Consider the following statements regarding the selection of recombinants using
alternative selectable markers based on chromogenic reactions:
I. The presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the
bacteria does not have an insert.
II. The presence of a chromogenic substrate gives white or colourless colonies if the plasmid in
the bacteria has an insert.
III. The blue colour is produced due to the insertional inactivation of the enzyme beta-
galactosidase.
IV. The white/colourless phenotype of recombinant colonies is due to the presence of an active,
functional beta-galactosidase enzyme.
Which of the statements given above are correct?
alternative selectable markers based on chromogenic reactions:
I. The presence of a chromogenic substrate gives blue coloured colonies if the plasmid in the
bacteria does not have an insert.
II. The presence of a chromogenic substrate gives white or colourless colonies if the plasmid in
the bacteria has an insert.
III. The blue colour is produced due to the insertional inactivation of the enzyme beta-
galactosidase.
IV. The white/colourless phenotype of recombinant colonies is due to the presence of an active,
functional beta-galactosidase enzyme.
Which of the statements given above are correct?
62.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Recombinant colonies are easily identified on a chromogenic agar plate because
they do not produce any colour and remain white.
Reason (R): The insertion of a foreign DNA fragment within the coding sequence of beta-
galactosidase results in the insertional inactivation of the enzyme.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Recombinant colonies are easily identified on a chromogenic agar plate because
they do not produce any colour and remain white.
Reason (R): The insertion of a foreign DNA fragment within the coding sequence of beta-
galactosidase results in the insertional inactivation of the enzyme.
In the light of the above statements, choose the correct answer:
63.Consider the following statements regarding the transfer of genes into plants using
bacterial pathogens:
I. Agrobacterium tumefaciens is a pathogen of several monocot plants that delivers a piece of
DNA to transform plant cells.
II. The piece of DNA delivered by Agrobacterium tumefaciens is known as 'T-DNA'.
III. The pathogen transforms normal plant cells into a tumor, which is then directed to produce
the chemicals required by the pathogen.
IV. The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens has been modified into a
cloning vector which is no longer pathogenic.
Which of the statements given above are correct?
bacterial pathogens:
I. Agrobacterium tumefaciens is a pathogen of several monocot plants that delivers a piece of
DNA to transform plant cells.
II. The piece of DNA delivered by Agrobacterium tumefaciens is known as 'T-DNA'.
III. The pathogen transforms normal plant cells into a tumor, which is then directed to produce
the chemicals required by the pathogen.
IV. The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens has been modified into a
cloning vector which is no longer pathogenic.
Which of the statements given above are correct?
64.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens has been
engineered into an ideal cloning vector for plant systems.
Reason (R): The engineered Ti plasmid is no longer pathogenic to plants but retains the
operational mechanism to deliver genes of interest into a variety of plants.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens has been
engineered into an ideal cloning vector for plant systems.
Reason (R): The engineered Ti plasmid is no longer pathogenic to plants but retains the
operational mechanism to deliver genes of interest into a variety of plants.
In the light of the above statements, choose the correct answer:
65.Consider the following statements regarding the transfer of foreign genes into animal cells:
I. Retroviruses in animals have the natural ability to transform normal cells into cancerous
cells.
II. Retroviruses have been engineered and disarmed to deliver desirable genes into animal host
cells.
III. Adenoviruses have been disarmed and are the primary vectors used to transform normal
animal cells into tumor cells for commercial protein production.
Which of the statements given above are correct?
I. Retroviruses in animals have the natural ability to transform normal cells into cancerous
cells.
II. Retroviruses have been engineered and disarmed to deliver desirable genes into animal host
cells.
III. Adenoviruses have been disarmed and are the primary vectors used to transform normal
animal cells into tumor cells for commercial protein production.
Which of the statements given above are correct?
66.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Geneticists have successfully learned the art of transferring genes into plants and
animals from pathogenic bacteria and viruses.
Reason (R): Pathogens like Agrobacterium tumefaciens and retroviruses have known for ages
how to deliver genes to transform eukaryotic host cells and force them to produce the chemicals
they require.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Geneticists have successfully learned the art of transferring genes into plants and
animals from pathogenic bacteria and viruses.
Reason (R): Pathogens like Agrobacterium tumefaciens and retroviruses have known for ages
how to deliver genes to transform eukaryotic host cells and force them to produce the chemicals
they require.
In the light of the above statements, choose the correct answer:
67.Consider the following statements regarding the physical-chemical properties of DNA and
cell membranes:
I. DNA is a highly hydrophilic molecule.
II. DNA is a highly hydrophobic molecule.
III. Due to its chemical nature, DNA cannot pass through lipid-rich cell membranes.
IV. In order to force bacteria to take up plasmids, they must first be made 'competent' to take
up DNA.
Which of the statements given above are correct?
cell membranes:
I. DNA is a highly hydrophilic molecule.
II. DNA is a highly hydrophobic molecule.
III. Due to its chemical nature, DNA cannot pass through lipid-rich cell membranes.
IV. In order to force bacteria to take up plasmids, they must first be made 'competent' to take
up DNA.
Which of the statements given above are correct?
68.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Treating host bacterial cells with a specific concentration of a divalent cation like
calcium increases their competence for DNA uptake.
Reason (R): Divalent cations neutralize the charges on the DNA backbone, thereby decreasing
the efficiency with which DNA enters through cell wall pores.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Treating host bacterial cells with a specific concentration of a divalent cation like
calcium increases their competence for DNA uptake.
Reason (R): Divalent cations neutralize the charges on the DNA backbone, thereby decreasing
the efficiency with which DNA enters through cell wall pores.
In the light of the above statements, choose the correct answer:
69.Consider the following statements regarding the physical steps of the heat shock protocol
used to force recombinant DNA into competent bacterial cells:
I. The protocol begins by incubating the cells with recombinant DNA on ice.
II. The cells are then placed briefly at a temperature of exactly 42°C to induce heat shock.
III. After heat shock, the cells are immediately transferred and kept at a warm recovery
temperature of 37°C before plating.
IV. The final step involves putting the cells back on ice before plating.
Which of the statements given above are correct?
used to force recombinant DNA into competent bacterial cells:
I. The protocol begins by incubating the cells with recombinant DNA on ice.
II. The cells are then placed briefly at a temperature of exactly 42°C to induce heat shock.
III. After heat shock, the cells are immediately transferred and kept at a warm recovery
temperature of 37°C before plating.
IV. The final step involves putting the cells back on ice before plating.
Which of the statements given above are correct?
70.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The specific sequence of incubating competent cells on ice, heating them at 42°C,
and returning them to ice is mandatory for bacterial transformation.
Reason (R): This physical temperature cycling protocol destabilizes cell wall components,
thereby enabling the bacteria to take up the recombinant DNA.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The specific sequence of incubating competent cells on ice, heating them at 42°C,
and returning them to ice is mandatory for bacterial transformation.
Reason (R): This physical temperature cycling protocol destabilizes cell wall components,
thereby enabling the bacteria to take up the recombinant DNA.
In the light of the above statements, choose the correct answer:
71.Consider the following statements regarding the alternative methods used to introduce
alien DNA into host cells:
I. In a method known as micro-injection, recombinant DNA is directly injected into the
cytoplasm of an animal cell.
II. In a method suitable for plants, cells are bombarded with high velocity micro-particles of
gold or tungsten coated with DNA.
III. The plant bombardment method is commercially known as biolistics or gene gun.
IV. The last method uses 'armed pathogen' vectors to actively infect the host and transfer
disease-causing genes.
Which of the statements given above are correct?
alien DNA into host cells:
I. In a method known as micro-injection, recombinant DNA is directly injected into the
cytoplasm of an animal cell.
II. In a method suitable for plants, cells are bombarded with high velocity micro-particles of
gold or tungsten coated with DNA.
III. The plant bombardment method is commercially known as biolistics or gene gun.
IV. The last method uses 'armed pathogen' vectors to actively infect the host and transfer
disease-causing genes.
Which of the statements given above are correct?
72.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Micro-injection is a highly successful direct gene transfer method restricted
primarily to animal cell hosts.
Reason (R): In micro-injection, the recombinant DNA is directly injected into the nucleus of an
animal cell using microscopic needles.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Micro-injection is a highly successful direct gene transfer method restricted
primarily to animal cell hosts.
Reason (R): In micro-injection, the recombinant DNA is directly injected into the nucleus of an
animal cell using microscopic needles.
In the light of the above statements, choose the correct answer:
73.Consider the following statements regarding the biolistics or gene gun technique:
I. The method is highly suitable for plant hosts.
II. Plant cells are bombarded with high velocity micro-particles of gold or tungsten.
III. These metal micro-particles must be coated with DNA molecules.
IV. In alternative configurations, micro-particles of platinum or silver are used due to lower
chemical reactivity.
Which of the statements given above are correct?
I. The method is highly suitable for plant hosts.
II. Plant cells are bombarded with high velocity micro-particles of gold or tungsten.
III. These metal micro-particles must be coated with DNA molecules.
IV. In alternative configurations, micro-particles of platinum or silver are used due to lower
chemical reactivity.
Which of the statements given above are correct?
74.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Disarmed pathogen vectors represent a highly efficient biological method to
deliver recombinant DNA into host cells.
Reason (R): When these disarmed pathogens are allowed to infect host cells, they actively
transfer the recombinant DNA into the host genome.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Disarmed pathogen vectors represent a highly efficient biological method to
deliver recombinant DNA into host cells.
Reason (R): When these disarmed pathogens are allowed to infect host cells, they actively
transfer the recombinant DNA into the host genome.
In the light of the above statements, choose the correct answer:
75.According to Section 9.3, which of the following represents the correct sequence of steps
involved in recombinant DNA technology?
I. Isolation of DNA followed by fragmentation of DNA by restriction endonucleases.
II. Ligation of the DNA fragment into a vector and transferring the recombinant DNA into the
host.
III. Isolation of the desired DNA fragment followed immediately by large-scale commercial
marketing.
IV. Culturing the host cells in a medium at large scale and extraction of the desired product.
Which of the combinations represents ONLY correct steps?
Choose the correct option:
involved in recombinant DNA technology?
I. Isolation of DNA followed by fragmentation of DNA by restriction endonucleases.
II. Ligation of the DNA fragment into a vector and transferring the recombinant DNA into the
host.
III. Isolation of the desired DNA fragment followed immediately by large-scale commercial
marketing.
IV. Culturing the host cells in a medium at large scale and extraction of the desired product.
Which of the combinations represents ONLY correct steps?
Choose the correct option:
76.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): In order to cut DNA with restriction enzymes, the cells must be broken open to
release DNA along with other macromolecules.
Reason (R): This cell lysis is achieved by treating host tissues with non-specific organic solvents
like chilled ethanol to dissolve cellulose and chitin barriers.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): In order to cut DNA with restriction enzymes, the cells must be broken open to
release DNA along with other macromolecules.
Reason (R): This cell lysis is achieved by treating host tissues with non-specific organic solvents
like chilled ethanol to dissolve cellulose and chitin barriers.
In the light of the above statements, choose the correct answer:
77.Consider the following statements regarding the specific enzymes used to digest cell wall
barriers in different host systems:
I. Bacterial cell walls are lysed using the enzyme lysozyme.
II. Plant cells are lysed using the enzyme chitinase.
III. Fungal cells are lysed using the enzyme cellulase.
Which of the statements given above is/are correct?
barriers in different host systems:
I. Bacterial cell walls are lysed using the enzyme lysozyme.
II. Plant cells are lysed using the enzyme chitinase.
III. Fungal cells are lysed using the enzyme cellulase.
Which of the statements given above is/are correct?
78.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): RNA and proteins present in the host cell lysate must be removed to obtain DNA
in pure form.
Reason (R): RNA is removed by treatment with protease, whereas proteins are removed by
treatment with ribonuclease.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): RNA and proteins present in the host cell lysate must be removed to obtain DNA
in pure form.
Reason (R): RNA is removed by treatment with protease, whereas proteins are removed by
treatment with ribonuclease.
In the light of the above statements, choose the correct answer:
79.Consider the following statements regarding the final precipitation and collection of
purified DNA:
I. Purified DNA ultimately precipitates out after the addition of chilled ethanol.
II. The precipitated DNA can be seen as a collection of fine threads in the suspension.
III. The DNA that separates out can be removed using a technique known as centrifugation.
IV. The DNA that separates out can be removed using a technique known as spooling.
Which of the statements given above are correct?
purified DNA:
I. Purified DNA ultimately precipitates out after the addition of chilled ethanol.
II. The precipitated DNA can be seen as a collection of fine threads in the suspension.
III. The DNA that separates out can be removed using a technique known as centrifugation.
IV. The DNA that separates out can be removed using a technique known as spooling.
Which of the statements given above are correct?
80.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Chilled ethanol is introduced as the final chemical step to precipitate the purified
DNA out of the suspension.
Reason (R): DNA is highly soluble in cold alcohol, which causes it to form visible fine threads
that immediately sediment at the bottom.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Chilled ethanol is introduced as the final chemical step to precipitate the purified
DNA out of the suspension.
Reason (R): DNA is highly soluble in cold alcohol, which causes it to form visible fine threads
that immediately sediment at the bottom.
In the light of the above statements, choose the correct answer:
81.Consider the following statements regarding the digestion and joining processes in
recombinant DNA construction:
I. Restriction enzyme digestions are checked by running agarose gel electrophoresis to monitor
fragment migration.
II. Vector DNA digestion is checked separately using the same gel electrophoresis technique.
III. Recombinant DNA is prepared by mixing the cut source DNA with the undigested circular
vector DNA, followed by ligase addition.
Which of the statements given above are correct?
recombinant DNA construction:
I. Restriction enzyme digestions are checked by running agarose gel electrophoresis to monitor
fragment migration.
II. Vector DNA digestion is checked separately using the same gel electrophoresis technique.
III. Recombinant DNA is prepared by mixing the cut source DNA with the undigested circular
vector DNA, followed by ligase addition.
Which of the statements given above are correct?
82.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): During gel electrophoresis to monitor digestion progress, DNA fragments are
forced to migrate towards the positive electrode.
Reason (R): The positive electrode in an electric field setup is called the cathode, which attracts
the negatively charged phosphate backbone of DNA.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): During gel electrophoresis to monitor digestion progress, DNA fragments are
forced to migrate towards the positive electrode.
Reason (R): The positive electrode in an electric field setup is called the cathode, which attracts
the negatively charged phosphate backbone of DNA.
In the light of the above statements, choose the correct answer:
83.Consider the following statements regarding the molecular components and reaction
conditions of PCR:
I. PCR stands for Polymerase Chain Reaction.
II. In this reaction, multiple copies of the gene of interest are synthesized in vitro.
III. The synthesis requires two sets of primers, which are small chemically synthesized
oligonucleotides complementary to regions of DNA.
IV. The primers are extended using the host cell's native RNA polymerase enzyme.
Which of the statements given above are correct?
conditions of PCR:
I. PCR stands for Polymerase Chain Reaction.
II. In this reaction, multiple copies of the gene of interest are synthesized in vitro.
III. The synthesis requires two sets of primers, which are small chemically synthesized
oligonucleotides complementary to regions of DNA.
IV. The primers are extended using the host cell's native RNA polymerase enzyme.
Which of the statements given above are correct?
84.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Each cycle of PCR consists of three major sequential steps: denaturation, primer
annealing, and extension of primers.
Reason (R): During primer annealing, the reaction mixture is heated to 94°C to break the
hydrogen bonds between complementary strands.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Each cycle of PCR consists of three major sequential steps: denaturation, primer
annealing, and extension of primers.
Reason (R): During primer annealing, the reaction mixture is heated to 94°C to break the
hydrogen bonds between complementary strands.
In the light of the above statements, choose the correct answer:
85.Consider the following statements regarding the quantitative yield of DNA amplification in
PCR:
I. If the process of replication of DNA is repeated many times, the segment of DNA can be
amplified to approximately billion times.
II. Repeating the cycles of replication results in the generation of approximately 1 billion copies
of the template gene.
III. This massive billion-fold amplification is theoretically achieved in exactly 30 cycles of a
standard PCR reaction.
IV. If the reaction is allowed to proceed for 100 cycles, it yields a maximum of 1 million copies
due to enzyme exhaustion.
Which of the statements given above are correct?
PCR:
I. If the process of replication of DNA is repeated many times, the segment of DNA can be
amplified to approximately billion times.
II. Repeating the cycles of replication results in the generation of approximately 1 billion copies
of the template gene.
III. This massive billion-fold amplification is theoretically achieved in exactly 30 cycles of a
standard PCR reaction.
IV. If the reaction is allowed to proceed for 100 cycles, it yields a maximum of 1 million copies
due to enzyme exhaustion.
Which of the statements given above are correct?
86.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Repeated cycles of high-temperature denaturation in PCR do not permanently
destroy the catalytic activity of the added DNA polymerase.
Reason (R): The DNA polymerase used in PCR is isolated from the thermostable bacterium
Thermus aquaticus and remains active at high temperatures.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Repeated cycles of high-temperature denaturation in PCR do not permanently
destroy the catalytic activity of the added DNA polymerase.
Reason (R): The DNA polymerase used in PCR is isolated from the thermostable bacterium
Thermus aquaticus and remains active at high temperatures.
In the light of the above statements, choose the correct answer:
87.Consider the following statements regarding the synthesis and ligation of PCR products:
I. Thermus aquaticus is a eukaryotic thermophilic alga that yields Taq polymerase.
II. The thermostable polymerase extends the primers using the deoxynucleoside triphosphates
provided in the reaction.
III. The genomic DNA serves as the initial template for primer extension.
IV. The amplified PCR fragment, if desired, can now be used to ligate with a vector for further
cloning.
Which of the statements given above are correct?
I. Thermus aquaticus is a eukaryotic thermophilic alga that yields Taq polymerase.
II. The thermostable polymerase extends the primers using the deoxynucleoside triphosphates
provided in the reaction.
III. The genomic DNA serves as the initial template for primer extension.
IV. The amplified PCR fragment, if desired, can now be used to ligate with a vector for further
cloning.
Which of the statements given above are correct?
88.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Spreading a mixture of transformed and untransformed E. coli host cells on agar
plates containing ampicillin permits only the transformants to grow.
Reason (R): The ampicillin resistance gene in the recombinant plasmid functions as a selectable
marker by conferring ampicillin resistance to the host.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Spreading a mixture of transformed and untransformed E. coli host cells on agar
plates containing ampicillin permits only the transformants to grow.
Reason (R): The ampicillin resistance gene in the recombinant plasmid functions as a selectable
marker by conferring ampicillin resistance to the host.
In the light of the above statements, choose the correct answer:
89.Consider the following statements regarding the expression of foreign genes in host cells:
I. In almost all recombinant technologies, the ultimate aim is to produce a desirable lipid.
II. If any protein encoding gene is expressed in a heterologous host, it is called a recombinant
protein.
III. The foreign gene gets expressed only under highly restricted, non-physiological anaerobic
conditions.
IV. The cells harbouring cloned genes of interest may be grown on a small scale in the
laboratory for initial extraction and purification.
Which of the statements given above are correct?
I. In almost all recombinant technologies, the ultimate aim is to produce a desirable lipid.
II. If any protein encoding gene is expressed in a heterologous host, it is called a recombinant
protein.
III. The foreign gene gets expressed only under highly restricted, non-physiological anaerobic
conditions.
IV. The cells harbouring cloned genes of interest may be grown on a small scale in the
laboratory for initial extraction and purification.
Which of the statements given above are correct?
90.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Multiplying cells in a continuous culture system produces a much larger biomass
leading to higher yields of the desired recombinant protein.
Reason (R): In a continuous culture setup, used medium is periodically drained out from one
side while fresh medium is added from the other to maintain the cells in their active log phase.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Multiplying cells in a continuous culture system produces a much larger biomass
leading to higher yields of the desired recombinant protein.
Reason (R): In a continuous culture setup, used medium is periodically drained out from one
side while fresh medium is added from the other to maintain the cells in their active log phase.
In the light of the above statements, choose the correct answer:
91.Consider the following statements regarding the matrix used in gel electrophoresis and its
physical-chemical resolution properties:
I. Agarose is a natural polymer extracted from marine red algae or sea weeds.
II. The concentration of agarose in the gel determines the pore size and sieving effect.
III. DNA fragments resolve strictly according to their molecular weight, where larger fragments
travel farther.
IV. The smaller the fragment size, the farther it moves through the sieving matrix.
Which of the statements given above are correct?
physical-chemical resolution properties:
I. Agarose is a natural polymer extracted from marine red algae or sea weeds.
II. The concentration of agarose in the gel determines the pore size and sieving effect.
III. DNA fragments resolve strictly according to their molecular weight, where larger fragments
travel farther.
IV. The smaller the fragment size, the farther it moves through the sieving matrix.
Which of the statements given above are correct?
92.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Gel electrophoresis uses an electric field to force negatively charged DNA
molecules through an agarose matrix.
Reason (R): In a density gradient centrifugation, molecules are separated based on their
sedimenting mass under centrifugal force.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Gel electrophoresis uses an electric field to force negatively charged DNA
molecules through an agarose matrix.
Reason (R): In a density gradient centrifugation, molecules are separated based on their
sedimenting mass under centrifugal force.
In the light of the above statements, choose the correct answer:
93.Consider the following statements regarding the visualization protocol for DNA bands in
gels:
I. Separated DNA fragments can be visualised in normal visible light without any staining if the
gel concentration is high.
II. Staining with ethidium bromide is mandatory for DNA visualization.
III. Stained gels must be exposed to ultraviolet (UV) radiation to excite the fluorophore.
IV. Under UV exposure, the stained DNA appears as brilliant blue bands.
Which of the statements given above are correct?
gels:
I. Separated DNA fragments can be visualised in normal visible light without any staining if the
gel concentration is high.
II. Staining with ethidium bromide is mandatory for DNA visualization.
III. Stained gels must be exposed to ultraviolet (UV) radiation to excite the fluorophore.
IV. Under UV exposure, the stained DNA appears as brilliant blue bands.
Which of the statements given above are correct?
94.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): The purified DNA fragments extracted from agarose gels are used directly in
constructing recombinant DNA.
Reason (R): The separated bands of DNA are physically cut out from the agarose gel and
chemically extracted from the gel piece in a step termed elution.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): The purified DNA fragments extracted from agarose gels are used directly in
constructing recombinant DNA.
Reason (R): The separated bands of DNA are physically cut out from the agarose gel and
chemically extracted from the gel piece in a step termed elution.
In the light of the above statements, choose the correct answer:
95.Consider the following statements regarding the loading of samples and migration patterns
shown in Figure 9.3:
I. DNA samples are loaded into wells located near the cathode (negative electrode) end of the gel.
II. Undigested DNA remains as a single, slow-migrating band located closest to the wells.
III. Digested DNA samples show multiple resolved bands migrating away from the wells.
IV. In Figure 9.3, lane 1 represents the digested DNA set, while lanes 2 to 4 represent the
undigested DNA set.
Which of the statements given above are correct?
shown in Figure 9.3:
I. DNA samples are loaded into wells located near the cathode (negative electrode) end of the gel.
II. Undigested DNA remains as a single, slow-migrating band located closest to the wells.
III. Digested DNA samples show multiple resolved bands migrating away from the wells.
IV. In Figure 9.3, lane 1 represents the digested DNA set, while lanes 2 to 4 represent the
undigested DNA set.
Which of the statements given above are correct?
96.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): Some bacterial plasmids may have only one or two copies per cell, whereas others
may maintain 15 to 100 copies per cell.
Reason (R): Bacteriophages generally have high copy numbers because they replicate in tight
coordinate control with host chromosomal DNA replication.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): Some bacterial plasmids may have only one or two copies per cell, whereas others
may maintain 15 to 100 copies per cell.
Reason (R): Bacteriophages generally have high copy numbers because they replicate in tight
coordinate control with host chromosomal DNA replication.
In the light of the above statements, choose the correct answer:
97.Consider the following statements regarding the recovery of target DNA linked to cloning
vectors:
I. If we ligate an alien DNA with a plasmid, we can multiply its numbers equal to the copy
number of the plasmid.
II. Linking an alien DNA to a bacteriophage yields a much lower copy number due to viral gene
exclusion.
III. Modern cloning vectors are specifically designed and engineered to facilitate easy selection
of recombinants from non-recombinants.
Which of the statements given above are correct?
vectors:
I. If we ligate an alien DNA with a plasmid, we can multiply its numbers equal to the copy
number of the plasmid.
II. Linking an alien DNA to a bacteriophage yields a much lower copy number due to viral gene
exclusion.
III. Modern cloning vectors are specifically designed and engineered to facilitate easy selection
of recombinants from non-recombinants.
Which of the statements given above are correct?
98.Given below are two statements, one is labelled as Assertion (A) and the other is labelled as
Reason (R):
Assertion (A): To facilitate cloning into a vector, three core features are strictly required: origin
of replication, selectable marker, and cloning sites.
Reason (R): In addition to these three core features, plant and animal cloning vectors require
specialized bacterial ribosomal binding sites to initiate host transcription.
In the light of the above statements, choose the correct answer:
Reason (R):
Assertion (A): To facilitate cloning into a vector, three core features are strictly required: origin
of replication, selectable marker, and cloning sites.
Reason (R): In addition to these three core features, plant and animal cloning vectors require
specialized bacterial ribosomal binding sites to initiate host transcription.
In the light of the above statements, choose the correct answer:
99.Consider the following statements regarding the origin of replication (ori) in vectors:
I. Any piece of DNA linked to the ori sequence can be made to replicate within host cells.
II. The ori sequence is solely responsible for initiating replication and has no influence over
plasmid copy numbers.
III. If one wants to recover a high number of copies of target DNA, it must be cloned in a vector
whose origin supports high copy numbers.
Which of the statements given above are correct?
I. Any piece of DNA linked to the ori sequence can be made to replicate within host cells.
II. The ori sequence is solely responsible for initiating replication and has no influence over
plasmid copy numbers.
III. If one wants to recover a high number of copies of target DNA, it must be cloned in a vector
whose origin supports high copy numbers.
Which of the statements given above are correct?
100.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Selectable markers are essential genetic elements that allow us to identify and
selectively permit the growth of transformants while eliminating non-transformants.
Reason (R): In a transformation procedure, a piece of foreign DNA is introduced into a host
bacterium, altering its genotypic and phenotypic properties.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Selectable markers are essential genetic elements that allow us to identify and
selectively permit the growth of transformants while eliminating non-transformants.
Reason (R): In a transformation procedure, a piece of foreign DNA is introduced into a host
bacterium, altering its genotypic and phenotypic properties.
In the light of the above statements, choose the correct answer:
101.According to the NCERT text, which of the following antibiotic resistance genes are
explicitly considered useful selectable markers for E. coli cloning vectors?
I. Ampicillin resistance gene.
II. Chloramphenicol resistance gene.
III. Tetracycline resistance gene.
IV. Kanamycin resistance gene.
Choose the correct option:
explicitly considered useful selectable markers for E. coli cloning vectors?
I. Ampicillin resistance gene.
II. Chloramphenicol resistance gene.
III. Tetracycline resistance gene.
IV. Kanamycin resistance gene.
Choose the correct option:
102.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Normal, wild-type Escherichia coli cells do not carry resistance against
ampicillin, chloramphenicol, tetracycline, or kanamycin.
Reason (R): Wild-type E. coli cells lack native plasmids and must be treated with divalent
cations to synthesize endogenous resistance proteins.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Normal, wild-type Escherichia coli cells do not carry resistance against
ampicillin, chloramphenicol, tetracycline, or kanamycin.
Reason (R): Wild-type E. coli cells lack native plasmids and must be treated with divalent
cations to synthesize endogenous resistance proteins.
In the light of the above statements, choose the correct answer:
103.Consider the following statements regarding the number and density of restriction
recognition sites in engineered vectors:
I. Cloning vectors require very few, preferably single, recognition sites for commonly used
restriction enzymes.
II. The presence of more than one recognition site for a single enzyme within a vector will
generate several fragments.
III. Generating several fragments during vector cleavage simplifies the linking of foreign DNA
by providing multiple insertion points.
Which of the statements given above are correct?
recognition sites in engineered vectors:
I. Cloning vectors require very few, preferably single, recognition sites for commonly used
restriction enzymes.
II. The presence of more than one recognition site for a single enzyme within a vector will
generate several fragments.
III. Generating several fragments during vector cleavage simplifies the linking of foreign DNA
by providing multiple insertion points.
Which of the statements given above are correct?
104.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In pBR322, the ligation of alien DNA is typically carried out at a restriction site
present in one of the two antibiotic resistance genes.
Reason (R): Splicing a foreign gene into a resistance gene enables the selection of recombinants
through the insertional inactivation of that specific antibiotic marker.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In pBR322, the ligation of alien DNA is typically carried out at a restriction site
present in one of the two antibiotic resistance genes.
Reason (R): Splicing a foreign gene into a resistance gene enables the selection of recombinants
through the insertional inactivation of that specific antibiotic marker.
In the light of the above statements, choose the correct answer:
105.Consider the following statements regarding the spatial organization of restriction sites in
E. coli cloning vector pBR322 shown in Figure 9.4:
I. The restriction sites Pst I and Pvu I are located within the ampicillin resistance (ampR) gene.
II. The restriction sites BamH I and Sal I are located within the tetracycline resistance (tetR)
gene.
III. The restriction sites EcoR I, Cla I, and Hind III are located outside the antibiotic resistance
genes.
IV. The restriction site Pvu II is located within the 'rop' gene region.
Which of the statements given above are correct?
E. coli cloning vector pBR322 shown in Figure 9.4:
I. The restriction sites Pst I and Pvu I are located within the ampicillin resistance (ampR) gene.
II. The restriction sites BamH I and Sal I are located within the tetracycline resistance (tetR)
gene.
III. The restriction sites EcoR I, Cla I, and Hind III are located outside the antibiotic resistance
genes.
IV. The restriction site Pvu II is located within the 'rop' gene region.
Which of the statements given above are correct?
106.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Cloning a gene of interest in a site located within the rop region of pBR322 can
affect the replication efficiency of the plasmid.
Reason (R): The 'rop' gene in pBR322 codes for specific proteins that are involved in the
replication of the plasmid.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Cloning a gene of interest in a site located within the rop region of pBR322 can
affect the replication efficiency of the plasmid.
Reason (R): The 'rop' gene in pBR322 codes for specific proteins that are involved in the
replication of the plasmid.
In the light of the above statements, choose the correct answer:
107.Consider the following statements regarding the phenotypic characteristics of E. coli cells
transformed with pBR322 containing a foreign insert at the BamHI site:
I. Recombinant E. coli cells are resistant to ampicillin but sensitive to tetracycline.
II. Non-recombinant E. coli cells are sensitive to ampicillin but resistant to tetracycline.
III. Non-recombinant transformant cells are resistant to both ampicillin and tetracycline.
IV. Untransformed recipient E. coli host cells are sensitive to both ampicillin and tetracycline.
Which of the statements given above are correct?
transformed with pBR322 containing a foreign insert at the BamHI site:
I. Recombinant E. coli cells are resistant to ampicillin but sensitive to tetracycline.
II. Non-recombinant E. coli cells are sensitive to ampicillin but resistant to tetracycline.
III. Non-recombinant transformant cells are resistant to both ampicillin and tetracycline.
IV. Untransformed recipient E. coli host cells are sensitive to both ampicillin and tetracycline.
Which of the statements given above are correct?
108.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Plating a mixture of transformants on ampicillin-containing medium is the first
step to select out cells carrying pBR322 plasmids (cloned at BamHI).
Reason (R): Non-transformant host E. coli cells are naturally sensitive to ampicillin and fail to
grow on ampicillin-supplemented agar plates.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Plating a mixture of transformants on ampicillin-containing medium is the first
step to select out cells carrying pBR322 plasmids (cloned at BamHI).
Reason (R): Non-transformant host E. coli cells are naturally sensitive to ampicillin and fail to
grow on ampicillin-supplemented agar plates.
In the light of the above statements, choose the correct answer:
109.Consider the following statements regarding the sequential replica plating steps for
pBR322 selection:
I. Transformants are first plated on ampicillin medium to select plasmid-carrying cells.
II. The colonies growing on the ampicillin plate are replica-plated onto a tetracycline-containing
plate.
III. The colonies that fail to grow on the tetracycline plate but grew on the ampicillin plate are
identified as recombinants.
IV. The colonies that grow on both plates are identified as recombinants because they carry the
foreign insert.
Which of the statements given above are correct?
pBR322 selection:
I. Transformants are first plated on ampicillin medium to select plasmid-carrying cells.
II. The colonies growing on the ampicillin plate are replica-plated onto a tetracycline-containing
plate.
III. The colonies that fail to grow on the tetracycline plate but grew on the ampicillin plate are
identified as recombinants.
IV. The colonies that grow on both plates are identified as recombinants because they carry the
foreign insert.
Which of the statements given above are correct?
110.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Selecting recombinants using antibiotic resistance genes in pBR322 is considered
a highly cumbersome procedure in laboratory practice.
Reason (R): The selection requires simultaneous plating on two separate plates having different
antibiotics to distinguish recombinants from non-recombinants.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Selecting recombinants using antibiotic resistance genes in pBR322 is considered
a highly cumbersome procedure in laboratory practice.
Reason (R): The selection requires simultaneous plating on two separate plates having different
antibiotics to distinguish recombinants from non-recombinants.
In the light of the above statements, choose the correct answer:
111.Consider the following statements regarding the alternative selectable markers developed
to replace cumbersome antibiotic selection:
I. Alternative selectable markers differentiate recombinants from non-recombinants based on
their ability to produce colour in the presence of a chromogenic substrate.
II. In these systems, recombinant plasmids are selected because they produce a brilliant, highly
visible fluorescent color.
III. The system relies on the insertion of foreign DNA within the coding sequence of the enzyme
beta-galactosidase.
IV. The enzyme beta-galactosidase is chemically inactivated by the insert, a process referred to
as insertional inactivation.
Which of the statements given above are correct?
to replace cumbersome antibiotic selection:
I. Alternative selectable markers differentiate recombinants from non-recombinants based on
their ability to produce colour in the presence of a chromogenic substrate.
II. In these systems, recombinant plasmids are selected because they produce a brilliant, highly
visible fluorescent color.
III. The system relies on the insertion of foreign DNA within the coding sequence of the enzyme
beta-galactosidase.
IV. The enzyme beta-galactosidase is chemically inactivated by the insert, a process referred to
as insertional inactivation.
Which of the statements given above are correct?
112.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Colonies carrying non-recombinant plasmids produce a highly characteristic
blue colour in the presence of a chromogenic substrate.
Reason (R): The coding sequence of beta-galactosidase in non-recombinant plasmids remains
uninterrupted, leading to the synthesis of a functional enzyme.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Colonies carrying non-recombinant plasmids produce a highly characteristic
blue colour in the presence of a chromogenic substrate.
Reason (R): The coding sequence of beta-galactosidase in non-recombinant plasmids remains
uninterrupted, leading to the synthesis of a functional enzyme.
In the light of the above statements, choose the correct answer:
113.Consider the following statements regarding the cloning vectors developed for eukaryotic
hosts:
I. Pathogens like Agrobacterium tumefaciens naturally deliver genes to transform plant cells.
II. Pathogens like retroviruses naturally deliver genes to transform animal cells.
III. Geneticists have engineered these tools of pathogens into useful vectors to deliver genes of
interest into eukaryotic hosts.
IV. Eukaryotic vectors must retain their wild-type pathogenicity to force host cells to replicate
the foreign insert DNA.
Which of the statements given above are correct?
hosts:
I. Pathogens like Agrobacterium tumefaciens naturally deliver genes to transform plant cells.
II. Pathogens like retroviruses naturally deliver genes to transform animal cells.
III. Geneticists have engineered these tools of pathogens into useful vectors to deliver genes of
interest into eukaryotic hosts.
IV. Eukaryotic vectors must retain their wild-type pathogenicity to force host cells to replicate
the foreign insert DNA.
Which of the statements given above are correct?
114.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Agrobacterium tumefaciens is a highly successful pathogen that naturally
transforms host cells by delivering a piece of T-DNA.
Reason (R): This pathogen is highly specific and naturally infects only cereal monocot crops like
wheat, rice, and maize.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Agrobacterium tumefaciens is a highly successful pathogen that naturally
transforms host cells by delivering a piece of T-DNA.
Reason (R): This pathogen is highly specific and naturally infects only cereal monocot crops like
wheat, rice, and maize.
In the light of the above statements, choose the correct answer:
115.Consider the following statements regarding the molecular events of T-DNA transfer in
plant hosts:
I. Agrobacterium tumefaciens delivers a piece of DNA known as 'T-DNA' to host cells.
II. The transferred T-DNA transforms normal plant cells into a tumor.
III. The T-DNA directs the tumor cells to produce the chemicals required by the pathogen.
IV. The chemicals produced by the tumor cells are explicitly described in the text as specific
amino acids and vitamins.
Which of the statements given above are correct?
plant hosts:
I. Agrobacterium tumefaciens delivers a piece of DNA known as 'T-DNA' to host cells.
II. The transferred T-DNA transforms normal plant cells into a tumor.
III. The T-DNA directs the tumor cells to produce the chemicals required by the pathogen.
IV. The chemicals produced by the tumor cells are explicitly described in the text as specific
amino acids and vitamins.
Which of the statements given above are correct?
116.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens can be used to
deliver genes of our interest into a variety of plant hosts.
Reason (R): The Ti plasmid has been modified into a disarmed cloning vector that is no longer
pathogenic to plants.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens can be used to
deliver genes of our interest into a variety of plant hosts.
Reason (R): The Ti plasmid has been modified into a disarmed cloning vector that is no longer
pathogenic to plants.
In the light of the above statements, choose the correct answer:
117.Consider the following statements regarding the disarming of retroviruses for animal cell
cloning:
I. Retroviruses have the natural ability to transform normal animal cells into cancerous cells.
II. In modern biotechnology, retroviruses have been disarmed and are used to deliver desirable
genes into animal host cells.
III. The disarmed retrovirus retains its oncogenic genes to force the host cell into rapid mitotic
division.
Which of the statements given above are correct?
cloning:
I. Retroviruses have the natural ability to transform normal animal cells into cancerous cells.
II. In modern biotechnology, retroviruses have been disarmed and are used to deliver desirable
genes into animal host cells.
III. The disarmed retrovirus retains its oncogenic genes to force the host cell into rapid mitotic
division.
Which of the statements given above are correct?
118.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): DNA is a highly hydrophilic molecule that is completely unable to pass through
cell membranes on its own.
Reason (R): Cell membranes consist of a hydrophobic lipid bilayer that presents an absolute
thermodynamic barrier to charged hydrophilic molecules.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): DNA is a highly hydrophilic molecule that is completely unable to pass through
cell membranes on its own.
Reason (R): Cell membranes consist of a hydrophobic lipid bilayer that presents an absolute
thermodynamic barrier to charged hydrophilic molecules.
In the light of the above statements, choose the correct answer:
119.Consider the following statements regarding the divalent cation competence protocol:
I. Bacterial cells are treated with a specific concentration of a divalent cation like calcium.
II. Calcium treatment increases the efficiency with which DNA enters the bacterium through
pores in its cell wall.
III. The calcium ions actively digest the peptidoglycan wall to open up large permanent gaps.
Which of the statements given above is/are correct?
I. Bacterial cells are treated with a specific concentration of a divalent cation like calcium.
II. Calcium treatment increases the efficiency with which DNA enters the bacterium through
pores in its cell wall.
III. The calcium ions actively digest the peptidoglycan wall to open up large permanent gaps.
Which of the statements given above is/are correct?
120.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles coated with DNA.
Reason (R): The micro-particles used in biolistics must consist of heavy metals like gold or
tungsten to ensure high momentum and biological inertness.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles coated with DNA.
Reason (R): The micro-particles used in biolistics must consist of heavy metals like gold or
tungsten to ensure high momentum and biological inertness.
In the light of the above statements, choose the correct answer:
121.Consider the following statements regarding the selection of transformants in E. coli
using antibiotic resistance genes:
I. Antibiotics like ampicillin, chloramphenicol, tetracycline, and kanamycin are widely used as
selectable markers in E. coli cloning.
II. Wild-type, non-transformed E. coli cells are naturally sensitive to all four of these antibiotics.
III. The selectable marker functions primarily to identify and selectively permit the growth of
non-transformants while eliminating transformants.
IV. Normal E. coli cells carry native resistance against ampicillin and tetracycline, making these
two antibiotics redundant for selection.
Which of the statements given above are correct?
using antibiotic resistance genes:
I. Antibiotics like ampicillin, chloramphenicol, tetracycline, and kanamycin are widely used as
selectable markers in E. coli cloning.
II. Wild-type, non-transformed E. coli cells are naturally sensitive to all four of these antibiotics.
III. The selectable marker functions primarily to identify and selectively permit the growth of
non-transformants while eliminating transformants.
IV. Normal E. coli cells carry native resistance against ampicillin and tetracycline, making these
two antibiotics redundant for selection.
Which of the statements given above are correct?
122.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The plasmid pBR322 contains unique cloning sites for EcoR I, Cla I, and Hind III
that are located outside the antibiotic resistance genes.
Reason (R): These three restriction sites are clustered together specifically within the 'rop' gene
region to facilitate replication regulation.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The plasmid pBR322 contains unique cloning sites for EcoR I, Cla I, and Hind III
that are located outside the antibiotic resistance genes.
Reason (R): These three restriction sites are clustered together specifically within the 'rop' gene
region to facilitate replication regulation.
In the light of the above statements, choose the correct answer:
123.Consider the following statements regarding the spatial organization of cloning sites in E.
coli vector pBR322:
I. Splicing foreign DNA at the BamH I or Sal I restriction sites will disrupt the tetracycline
resistance (tetR) gene.
II. Splicing foreign DNA at the Pst I or Pvu I restriction sites will disrupt the ampicillin
resistance (ampR) gene.
III. The restriction sites BamH I and Sal I are located within the ampicillin resistance (ampR)
gene region.
IV. The restriction sites Pst I and Pvu I are located within the tetracycline resistance (tetR) gene
region.
Which of the statements given above are correct?
coli vector pBR322:
I. Splicing foreign DNA at the BamH I or Sal I restriction sites will disrupt the tetracycline
resistance (tetR) gene.
II. Splicing foreign DNA at the Pst I or Pvu I restriction sites will disrupt the ampicillin
resistance (ampR) gene.
III. The restriction sites BamH I and Sal I are located within the ampicillin resistance (ampR)
gene region.
IV. The restriction sites Pst I and Pvu I are located within the tetracycline resistance (tetR) gene
region.
Which of the statements given above are correct?
124.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Recombinant E. coli cells containing pBR322 plasmids with a foreign insert at the
Pst I site are sensitive to ampicillin but resistant to tetracycline.
Reason (R): Splicing a foreign gene into the Pst I site of pBR322 leads to the insertional
inactivation of the ampicillin resistance gene while leaving the tetracycline resistance gene
intact.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Recombinant E. coli cells containing pBR322 plasmids with a foreign insert at the
Pst I site are sensitive to ampicillin but resistant to tetracycline.
Reason (R): Splicing a foreign gene into the Pst I site of pBR322 leads to the insertional
inactivation of the ampicillin resistance gene while leaving the tetracycline resistance gene
intact.
In the light of the above statements, choose the correct answer:
125.Consider the following statements regarding the 'rop' region of the E. coli cloning vector
pBR322:
I. The 'rop' region codes for specific proteins that are involved in the replication of the plasmid.
II. The unique restriction site present in the rop region is Pvu II.
III. The 'rop' gene is an acronym that stands for 'ribosomal outer protein', which initiates host
cell translation.
IV. Splicing a foreign gene at the Pvu II site disrupts the rop gene, which can alter the copy
number of the plasmid in host cells.
Which of the statements given above are correct?
pBR322:
I. The 'rop' region codes for specific proteins that are involved in the replication of the plasmid.
II. The unique restriction site present in the rop region is Pvu II.
III. The 'rop' gene is an acronym that stands for 'ribosomal outer protein', which initiates host
cell translation.
IV. Splicing a foreign gene at the Pvu II site disrupts the rop gene, which can alter the copy
number of the plasmid in host cells.
Which of the statements given above are correct?
126.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): One of the antibiotic resistance genes in pBR322 helps in selecting the
transformants, whereas the other gets inactivated and helps in selecting the recombinants.
Reason (R): In transformation, wild-type E. coli cells are treated with calcium to ensure they
take up plasmids and express both resistance markers simultaneously.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): One of the antibiotic resistance genes in pBR322 helps in selecting the
transformants, whereas the other gets inactivated and helps in selecting the recombinants.
Reason (R): In transformation, wild-type E. coli cells are treated with calcium to ensure they
take up plasmids and express both resistance markers simultaneously.
In the light of the above statements, choose the correct answer:
127.Consider the following statements regarding the selection steps for E. coli cells
transformed with a pBR322 recombinant plasmid cloned at the BamHI site:
I. The transformants are first plated on ampicillin-containing medium to select plasmid-
carrying cells.
II. The colonies growing on the ampicillin medium are replica-plated onto a tetracycline-
containing medium.
III. Recombinant colonies will fail to grow on the ampicillin medium but will grow on the
tetracycline medium.
IV. Non-recombinant colonies will grow on the medium containing both ampicillin and
tetracycline.
Which of the statements given above are correct?
transformed with a pBR322 recombinant plasmid cloned at the BamHI site:
I. The transformants are first plated on ampicillin-containing medium to select plasmid-
carrying cells.
II. The colonies growing on the ampicillin medium are replica-plated onto a tetracycline-
containing medium.
III. Recombinant colonies will fail to grow on the ampicillin medium but will grow on the
tetracycline medium.
IV. Non-recombinant colonies will grow on the medium containing both ampicillin and
tetracycline.
Which of the statements given above are correct?
128.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Plating the transformation mixture on ampicillin-containing medium is the first
step to select out cells carrying pBR322 plasmids (cloned at BamHI).
Reason (R): Non-transformant host E. coli cells are naturally sensitive to ampicillin and fail to
grow on ampicillin-supplemented agar plates.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Plating the transformation mixture on ampicillin-containing medium is the first
step to select out cells carrying pBR322 plasmids (cloned at BamHI).
Reason (R): Non-transformant host E. coli cells are naturally sensitive to ampicillin and fail to
grow on ampicillin-supplemented agar plates.
In the light of the above statements, choose the correct answer:
129.Consider the following statements regarding the sequential replica plating steps for
pBR322 selection:
I. Transformants are first plated on ampicillin medium to select plasmid-carrying cells.
II. The colonies growing on the ampicillin plate are replica-plated onto a tetracycline-containing
plate.
III. The colonies that fail to grow on the tetracycline plate but grew on the ampicillin plate are
identified as recombinants.
IV. The colonies that grow on both plates are identified as recombinants because they carry the
foreign insert.
Which of the statements given above are correct?
pBR322 selection:
I. Transformants are first plated on ampicillin medium to select plasmid-carrying cells.
II. The colonies growing on the ampicillin plate are replica-plated onto a tetracycline-containing
plate.
III. The colonies that fail to grow on the tetracycline plate but grew on the ampicillin plate are
identified as recombinants.
IV. The colonies that grow on both plates are identified as recombinants because they carry the
foreign insert.
Which of the statements given above are correct?
130.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Selecting recombinants using antibiotic resistance genes in pBR322 is considered
a highly cumbersome procedure in laboratory practice.
Reason (R): The selection requires simultaneous plating on two separate plates having different
antibiotics to distinguish recombinants from non-recombinants.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Selecting recombinants using antibiotic resistance genes in pBR322 is considered
a highly cumbersome procedure in laboratory practice.
Reason (R): The selection requires simultaneous plating on two separate plates having different
antibiotics to distinguish recombinants from non-recombinants.
In the light of the above statements, choose the correct answer:
131.Consider the following statements regarding the alternative selectable markers developed
to replace cumbersome antibiotic selection:
I. Alternative selectable markers differentiate recombinants from non-recombinants based on
their ability to produce colour in the presence of a chromogenic substrate.
II. In these systems, recombinant plasmids are selected because they produce a brilliant, highly
visible fluorescent color.
III. The system relies on the insertion of foreign DNA within the coding sequence of the enzyme
beta-galactosidase.
IV. The enzyme beta-galactosidase is chemically inactivated by the insert, a process referred to
as insertional inactivation.
Which of the statements given above are correct?
to replace cumbersome antibiotic selection:
I. Alternative selectable markers differentiate recombinants from non-recombinants based on
their ability to produce colour in the presence of a chromogenic substrate.
II. In these systems, recombinant plasmids are selected because they produce a brilliant, highly
visible fluorescent color.
III. The system relies on the insertion of foreign DNA within the coding sequence of the enzyme
beta-galactosidase.
IV. The enzyme beta-galactosidase is chemically inactivated by the insert, a process referred to
as insertional inactivation.
Which of the statements given above are correct?
132.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Colonies carrying non-recombinant plasmids produce a highly characteristic
blue colour in the presence of a chromogenic substrate.
Reason (R): The coding sequence of beta-galactosidase in non-recombinant plasmids remains
uninterrupted, leading to the synthesis of a functional enzyme.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Colonies carrying non-recombinant plasmids produce a highly characteristic
blue colour in the presence of a chromogenic substrate.
Reason (R): The coding sequence of beta-galactosidase in non-recombinant plasmids remains
uninterrupted, leading to the synthesis of a functional enzyme.
In the light of the above statements, choose the correct answer:
133.Consider the following statements regarding the cloning vectors developed for eukaryotic
hosts:
I. Pathogens like Agrobacterium tumefaciens naturally deliver genes to transform plant cells.
II. Pathogens like retroviruses naturally deliver genes to transform animal cells.
III. Geneticists have engineered these tools of pathogens into useful vectors to deliver genes of
interest into eukaryotic hosts.
IV. Eukaryotic vectors must retain their wild-type pathogenicity to force host cells to replicate
the foreign insert DNA.
Which of the statements given above are correct?
hosts:
I. Pathogens like Agrobacterium tumefaciens naturally deliver genes to transform plant cells.
II. Pathogens like retroviruses naturally deliver genes to transform animal cells.
III. Geneticists have engineered these tools of pathogens into useful vectors to deliver genes of
interest into eukaryotic hosts.
IV. Eukaryotic vectors must retain their wild-type pathogenicity to force host cells to replicate
the foreign insert DNA.
Which of the statements given above are correct?
134.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Agrobacterium tumefaciens is a highly successful pathogen that naturally
transforms host cells by delivering a piece of T-DNA.
Reason (R): This pathogen is highly specific and naturally infects only cereal monocot crops like
wheat, rice, and maize.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Agrobacterium tumefaciens is a highly successful pathogen that naturally
transforms host cells by delivering a piece of T-DNA.
Reason (R): This pathogen is highly specific and naturally infects only cereal monocot crops like
wheat, rice, and maize.
In the light of the above statements, choose the correct answer:
135.Consider the following statements regarding the molecular events of T-DNA transfer in
plant hosts:
I. Agrobacterium tumefaciens delivers a piece of DNA known as 'T-DNA' to host cells.
II. The transferred T-DNA transforms normal plant cells into a tumor.
III. The T-DNA directs the tumor cells to produce the chemicals required by the pathogen.
IV. The chemicals produced by the tumor cells are explicitly described in the text as specific
amino acids and vitamins.
Which of the statements given above are correct?
plant hosts:
I. Agrobacterium tumefaciens delivers a piece of DNA known as 'T-DNA' to host cells.
II. The transferred T-DNA transforms normal plant cells into a tumor.
III. The T-DNA directs the tumor cells to produce the chemicals required by the pathogen.
IV. The chemicals produced by the tumor cells are explicitly described in the text as specific
amino acids and vitamins.
Which of the statements given above are correct?
136.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens can be used to
deliver genes of our interest into a variety of plant hosts.
Reason (R): The Ti plasmid has been modified into a disarmed cloning vector that is no longer
pathogenic to plants.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens can be used to
deliver genes of our interest into a variety of plant hosts.
Reason (R): The Ti plasmid has been modified into a disarmed cloning vector that is no longer
pathogenic to plants.
In the light of the above statements, choose the correct answer:
137.Consider the following statements regarding the disarming of retroviruses for animal cell
cloning:
I. Retroviruses have the natural ability to transform normal animal cells into cancerous cells.
II. In modern biotechnology, retroviruses have been disarmed and are used to deliver desirable
genes into animal host cells.
III. The disarmed retrovirus retains its oncogenic genes to force the host cell into rapid mitotic
division.
Which of the statements given above are correct?
cloning:
I. Retroviruses have the natural ability to transform normal animal cells into cancerous cells.
II. In modern biotechnology, retroviruses have been disarmed and are used to deliver desirable
genes into animal host cells.
III. The disarmed retrovirus retains its oncogenic genes to force the host cell into rapid mitotic
division.
Which of the statements given above are correct?
138.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): DNA is a highly hydrophilic molecule that is completely unable to pass through
cell membranes on its own.
Reason (R): Cell membranes consist of a hydrophobic lipid bilayer that presents an absolute
thermodynamic barrier to charged hydrophilic molecules.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): DNA is a highly hydrophilic molecule that is completely unable to pass through
cell membranes on its own.
Reason (R): Cell membranes consist of a hydrophobic lipid bilayer that presents an absolute
thermodynamic barrier to charged hydrophilic molecules.
In the light of the above statements, choose the correct answer:
139.Consider the following statements regarding the divalent cation competence protocol:
I. Bacterial cells are treated with a specific concentration of a divalent cation like calcium.
II. Calcium treatment increases the efficiency with which DNA enters the bacterium through
pores in its cell wall.
III. The calcium ions actively digest the peptidoglycan wall to open up large permanent gaps.
Which of the statements given above is/are correct?
I. Bacterial cells are treated with a specific concentration of a divalent cation like calcium.
II. Calcium treatment increases the efficiency with which DNA enters the bacterium through
pores in its cell wall.
III. The calcium ions actively digest the peptidoglycan wall to open up large permanent gaps.
Which of the statements given above is/are correct?
140.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles coated with DNA.
Reason (R): The micro-particles used in biolistics must consist of heavy metals like gold or
tungsten to ensure high momentum and biological inertness.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles coated with DNA.
Reason (R): The micro-particles used in biolistics must consist of heavy metals like gold or
tungsten to ensure high momentum and biological inertness.
In the light of the above statements, choose the correct answer:
141.Consider the following statements regarding the micro-injection gene transfer method:
I. Micro-injection is highly suitable and primarily restricted to animal hosts.
II. Recombinant DNA is directly injected into the nucleus of the target cell.
III. Micro-injection is the primary method used to deliver DNA to plant cells containing thick
cell walls.
IV. Splicing of DNA during micro-injection requires helper viruses to integrate the needle-
delivered plasmid.
Which of the statements given above are correct?
I. Micro-injection is highly suitable and primarily restricted to animal hosts.
II. Recombinant DNA is directly injected into the nucleus of the target cell.
III. Micro-injection is the primary method used to deliver DNA to plant cells containing thick
cell walls.
IV. Splicing of DNA during micro-injection requires helper viruses to integrate the needle-
delivered plasmid.
Which of the statements given above are correct?
142.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Micro-injection represents a direct, vector-free method to introduce recombinant
DNA into host animal cells.
Reason (R): Disarmed retroviruses deliver foreign genes into animal genomes through viral
infection and replication pathways.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Micro-injection represents a direct, vector-free method to introduce recombinant
DNA into host animal cells.
Reason (R): Disarmed retroviruses deliver foreign genes into animal genomes through viral
infection and replication pathways.
In the light of the above statements, choose the correct answer:
143.According to the NCERT text, which of the following represents the correct biological
target matching for the three modern gene delivery methods?
I. Micro-injection: Directly targets the nucleus of animal cells.
II. Biolistics (Gene Gun): Targets plant cells by bombarding them with metal micro-particles.
III. Disarmed Pathogens: Allowed to infect the host cells to transfer the recombinant DNA.
Choose the correct option:
target matching for the three modern gene delivery methods?
I. Micro-injection: Directly targets the nucleus of animal cells.
II. Biolistics (Gene Gun): Targets plant cells by bombarding them with metal micro-particles.
III. Disarmed Pathogens: Allowed to infect the host cells to transfer the recombinant DNA.
Choose the correct option:
144.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Agrobacterium tumefaciens naturally delivers T-DNA to plant cells, inducing
crown gall tumor growth.
Reason (R): The 'T-DNA' stands for 'transcription DNA', which is highly active during host
RNA synthesis.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Agrobacterium tumefaciens naturally delivers T-DNA to plant cells, inducing
crown gall tumor growth.
Reason (R): The 'T-DNA' stands for 'transcription DNA', which is highly active during host
RNA synthesis.
In the light of the above statements, choose the correct answer:
145.Consider the following statements regarding the physical characteristics and collection of
DNA precipitated using chilled ethanol as shown in Figure 9.5:
I. Addition of chilled ethanol causes the purified DNA to form fine, highly visible white threads.
II. The threads appear in the suspension and are collected by spooling.
III. Spooling is performed by winding the DNA threads onto a glass rod.
IV. The precipitated DNA threads are completely insoluble in water and must be stored
permanently in cold alcohol.
Which of the statements given above are correct?
DNA precipitated using chilled ethanol as shown in Figure 9.5:
I. Addition of chilled ethanol causes the purified DNA to form fine, highly visible white threads.
II. The threads appear in the suspension and are collected by spooling.
III. Spooling is performed by winding the DNA threads onto a glass rod.
IV. The precipitated DNA threads are completely insoluble in water and must be stored
permanently in cold alcohol.
Which of the statements given above are correct?
146.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In genetic engineering, isolated genomic DNA must be purified to absolute
homogeneity, free from RNA, proteins, and lipids.
Reason (R): Restriction enzymes are highly sensitive to cellular contaminants and are easily
inhibited by co-purified proteins and lipids in vitro.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In genetic engineering, isolated genomic DNA must be purified to absolute
homogeneity, free from RNA, proteins, and lipids.
Reason (R): Restriction enzymes are highly sensitive to cellular contaminants and are easily
inhibited by co-purified proteins and lipids in vitro.
In the light of the above statements, choose the correct answer:
147.Consider the following statements regarding the bacterium Thermus aquaticus which
yields Taq polymerase:
I. Thermus aquaticus is a thermophilic bacterium isolated from hot springs and hydrothermal
vents.
II. The DNA polymerase isolated from this bacterium is naturally thermostable.
III. Thermus aquaticus is a hyperthermophilic alga that lacks a defined peptidoglycan wall.
IV. The Taq polymerase enzyme remains active during the high temperature denaturation step
of PCR.
Which of the statements given above are correct?
yields Taq polymerase:
I. Thermus aquaticus is a thermophilic bacterium isolated from hot springs and hydrothermal
vents.
II. The DNA polymerase isolated from this bacterium is naturally thermostable.
III. Thermus aquaticus is a hyperthermophilic alga that lacks a defined peptidoglycan wall.
IV. The Taq polymerase enzyme remains active during the high temperature denaturation step
of PCR.
Which of the statements given above are correct?
148.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): During the extension phase of a PCR cycle, Taq polymerase synthesizes
complementary strands in the 5′ 3′ direction.
Reason (R): DNA polymerases can only add deoxynucleotides to the free 3′-OH end of a primer,
thereby extending the chain in the 5′ 3′ direction.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): During the extension phase of a PCR cycle, Taq polymerase synthesizes
complementary strands in the 5′ 3′ direction.
Reason (R): DNA polymerases can only add deoxynucleotides to the free 3′-OH end of a primer,
thereby extending the chain in the 5′ 3′ direction.
In the light of the above statements, choose the correct answer:
149.Consider the following statements regarding the scale and environmental parameters
optimized inside industrial bioreactors:
I. Bioreactors are large vessels in which raw materials are biologically converted into specific
products using cells or enzymes.
II. A standard commercial bioreactor typically processes culture volumes ranging from 100 to
1000 litres.
III. The bioreactor provides optimal conditions by controlling temperature, pH, substrate, salts,
vitamins, and oxygen.
IV. Industrial bioreactors typically process culture volumes ranging from 10,000 to 100,000
litres to ensure maximum commercial viability.
Which of the statements given above are correct?
optimized inside industrial bioreactors:
I. Bioreactors are large vessels in which raw materials are biologically converted into specific
products using cells or enzymes.
II. A standard commercial bioreactor typically processes culture volumes ranging from 100 to
1000 litres.
III. The bioreactor provides optimal conditions by controlling temperature, pH, substrate, salts,
vitamins, and oxygen.
IV. Industrial bioreactors typically process culture volumes ranging from 10,000 to 100,000
litres to ensure maximum commercial viability.
Which of the statements given above are correct?
150.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Stirred-tank bioreactors are designed with a cylindrical body or a curved base.
Reason (R): The cylindrical body and curved base facilitate the highly efficient mixing of the
reactor contents.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Stirred-tank bioreactors are designed with a cylindrical body or a curved base.
Reason (R): The cylindrical body and curved base facilitate the highly efficient mixing of the
reactor contents.
In the light of the above statements, choose the correct answer:
151.Consider the following statements regarding the selection of recombinants and non-
recombinants in a pBR322 cloning experiment at the BamHI site:
I. The transformants are grown on ampicillin-containing medium to select out the non-
transformants.
II. Recombinant transformants grow on ampicillin but fail to grow on tetracycline-containing
medium.
III. Non-recombinant transformants fail to grow on both ampicillin and tetracycline-containing
media.
IV. Untransformed host cells grow on the medium containing both antibiotics.
Which of the statements given above are correct?
recombinants in a pBR322 cloning experiment at the BamHI site:
I. The transformants are grown on ampicillin-containing medium to select out the non-
transformants.
II. Recombinant transformants grow on ampicillin but fail to grow on tetracycline-containing
medium.
III. Non-recombinant transformants fail to grow on both ampicillin and tetracycline-containing
media.
IV. Untransformed host cells grow on the medium containing both antibiotics.
Which of the statements given above are correct?
152.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Selection of recombinants due to inactivation of antibiotics is described as a
highly cumbersome procedure.
Reason (R): The antibiotic selection protocol requires simultaneous plating on two separate
plates having different antibiotics to identify a single recombinant colony.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Selection of recombinants due to inactivation of antibiotics is described as a
highly cumbersome procedure.
Reason (R): The antibiotic selection protocol requires simultaneous plating on two separate
plates having different antibiotics to identify a single recombinant colony.
In the light of the above statements, choose the correct answer:
153.Consider the following statements regarding the alternative selectable markers developed
to replace cumbersome antibiotic selection:
I. Alternative selectable markers differentiate recombinants from non-recombinants based on
their ability to produce colour in the presence of a chromogenic substrate.
II. In these systems, recombinant plasmids are selected because they produce a brilliant, highly
visible fluorescent color.
III. The system relies on the insertion of foreign DNA within the coding sequence of the enzyme
beta-galactosidase.
IV. The enzyme beta-galactosidase is chemically inactivated by the insert, a process referred to
as insertional inactivation.
Which of the statements given above are correct?
to replace cumbersome antibiotic selection:
I. Alternative selectable markers differentiate recombinants from non-recombinants based on
their ability to produce colour in the presence of a chromogenic substrate.
II. In these systems, recombinant plasmids are selected because they produce a brilliant, highly
visible fluorescent color.
III. The system relies on the insertion of foreign DNA within the coding sequence of the enzyme
beta-galactosidase.
IV. The enzyme beta-galactosidase is chemically inactivated by the insert, a process referred to
as insertional inactivation.
Which of the statements given above are correct?
154.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Colonies carrying non-recombinant plasmids produce a highly characteristic
blue colour in the presence of a chromogenic substrate.
Reason (R): The coding sequence of beta-galactosidase in non-recombinant plasmids remains
uninterrupted, leading to the synthesis of a functional enzyme.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Colonies carrying non-recombinant plasmids produce a highly characteristic
blue colour in the presence of a chromogenic substrate.
Reason (R): The coding sequence of beta-galactosidase in non-recombinant plasmids remains
uninterrupted, leading to the synthesis of a functional enzyme.
In the light of the above statements, choose the correct answer:
155.Consider the following statements regarding the enzymatic and genetic parameters of
insertional inactivation in chromogenic selection:
I. The recombinant DNA is inserted specifically within the coding sequence of the enzyme beta-
galactosidase.
II. The target enzyme is responsible for catalyzing the synthesis of galactose and glucose from
lactose host substrates.
III. The insertion results in the inactivation of the gene for synthesis of this enzyme, a process
termed insertional inactivation.
IV. The presence of the insert causes the host cells to become highly sensitive to ampicillin,
combining color and drug selection.
Which of the statements given above are correct?
insertional inactivation in chromogenic selection:
I. The recombinant DNA is inserted specifically within the coding sequence of the enzyme beta-
galactosidase.
II. The target enzyme is responsible for catalyzing the synthesis of galactose and glucose from
lactose host substrates.
III. The insertion results in the inactivation of the gene for synthesis of this enzyme, a process
termed insertional inactivation.
IV. The presence of the insert causes the host cells to become highly sensitive to ampicillin,
combining color and drug selection.
Which of the statements given above are correct?
156.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Recombinant colonies are identified on a chromogenic agar plate because they
completely fail to produce any colour.
Reason (R): The presence of a foreign DNA insert disrupts the coding sequence of beta-
galactosidase, thereby preventing the synthesis of a active enzyme.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Recombinant colonies are identified on a chromogenic agar plate because they
completely fail to produce any colour.
Reason (R): The presence of a foreign DNA insert disrupts the coding sequence of beta-
galactosidase, thereby preventing the synthesis of a active enzyme.
In the light of the above statements, choose the correct answer:
157.Consider the following statements regarding the phenotypic results of chromogenic
screening in recombinant E. coli cultures:
I. The screening utilizes a chromogenic substrate added to the growth agar medium.
II. Non-recombinant colonies produce a highly visible blue colour, indicating an active,
functional beta-galactosidase gene.
III. Recombinant colonies do not produce any colour and remain white, indicating insertional
inactivation.
IV. If the host E. coli lacks native beta-galactosidase altogether, even non-recombinant colonies
will remain white, acting as a false positive.
Which of the statements given above are correct?
screening in recombinant E. coli cultures:
I. The screening utilizes a chromogenic substrate added to the growth agar medium.
II. Non-recombinant colonies produce a highly visible blue colour, indicating an active,
functional beta-galactosidase gene.
III. Recombinant colonies do not produce any colour and remain white, indicating insertional
inactivation.
IV. If the host E. coli lacks native beta-galactosidase altogether, even non-recombinant colonies
will remain white, acting as a false positive.
Which of the statements given above are correct?
158.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Alternative selectable markers based on chromogenic reactions have largely
replaced the original dual-antibiotic selection methods of pBR322.
Reason (R): Differentiating recombinants from non-recombinants based on color production is
a single-step visual procedure that avoids dual replica plating.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Alternative selectable markers based on chromogenic reactions have largely
replaced the original dual-antibiotic selection methods of pBR322.
Reason (R): Differentiating recombinants from non-recombinants based on color production is
a single-step visual procedure that avoids dual replica plating.
In the light of the above statements, choose the correct answer:
159.Consider the following statements regarding the chromogenic substrate used in
blue/white screening:
I. The substrate is cleaved by active beta-galactosidase to yield a blue colored product.
II. The chromogenic substrate is explicitly named in the NCERT biotechnology chapter as X-
gal.
III. The NCERT text simply refers to the chemical reagent as 'a chromogenic substrate' without
providing a specific chemical acronym.
IV. In alternative configurations, a fluorescent substrate is used to yield bright green colonies.
Which of the statements given above are correct?
blue/white screening:
I. The substrate is cleaved by active beta-galactosidase to yield a blue colored product.
II. The chromogenic substrate is explicitly named in the NCERT biotechnology chapter as X-
gal.
III. The NCERT text simply refers to the chemical reagent as 'a chromogenic substrate' without
providing a specific chemical acronym.
IV. In alternative configurations, a fluorescent substrate is used to yield bright green colonies.
Which of the statements given above are correct?
160.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Selectable markers represent one of the three core required features that
facilitate cloning into a vector.
Reason (R): A vector requires a selectable marker specifically to initiate high-copy plasmid
replication and regulate the translation of cloned genes.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Selectable markers represent one of the three core required features that
facilitate cloning into a vector.
Reason (R): A vector requires a selectable marker specifically to initiate high-copy plasmid
replication and regulate the translation of cloned genes.
In the light of the above statements, choose the correct answer:
161.Consider the following statements regarding the phenotypic results of different host
configurations in pBR322 cloning:
I. Host E. coli containing wild-type pBR322 (no insert) grows on plates containing both
ampicillin and tetracycline.
II. Host E. coli containing pBR322 with a BamHI insert grows on ampicillin plates but dies on
tetracycline plates.
III. Host E. coli containing pBR322 with a PstI insert grows on tetracycline plates but dies on
ampicillin plates.
IV. Untransformed E. coli host cells die on both ampicillin and tetracycline plates.
Which of the statements given above are correct?
configurations in pBR322 cloning:
I. Host E. coli containing wild-type pBR322 (no insert) grows on plates containing both
ampicillin and tetracycline.
II. Host E. coli containing pBR322 with a BamHI insert grows on ampicillin plates but dies on
tetracycline plates.
III. Host E. coli containing pBR322 with a PstI insert grows on tetracycline plates but dies on
ampicillin plates.
IV. Untransformed E. coli host cells die on both ampicillin and tetracycline plates.
Which of the statements given above are correct?
162.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Recombinant E. coli cells containing pBR322 plasmids with a foreign insert at the
Sal I site are sensitive to tetracycline but resistant to ampicillin.
Reason (R): Splicing a foreign gene into the Sal I site of pBR322 leads to the insertional
inactivation of the tetracycline resistance gene while leaving the ampicillin resistance gene
intact.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Recombinant E. coli cells containing pBR322 plasmids with a foreign insert at the
Sal I site are sensitive to tetracycline but resistant to ampicillin.
Reason (R): Splicing a foreign gene into the Sal I site of pBR322 leads to the insertional
inactivation of the tetracycline resistance gene while leaving the ampicillin resistance gene
intact.
In the light of the above statements, choose the correct answer:
163.Consider the following statements regarding the phenotypic characteristics of E. coli cells
transformed with a pBR322 plasmid containing a foreign insert at the Cla I site:
I. Splicing a foreign gene at the Cla I site will lead to the insertional inactivation of the
ampicillin resistance gene.
II. Transformants containing the Cla I insert are resistant to both ampicillin and tetracycline.
III. Transformants containing the Cla I insert are sensitive to both ampicillin and tetracycline.
Which of the statements given above is/are correct?
transformed with a pBR322 plasmid containing a foreign insert at the Cla I site:
I. Splicing a foreign gene at the Cla I site will lead to the insertional inactivation of the
ampicillin resistance gene.
II. Transformants containing the Cla I insert are resistant to both ampicillin and tetracycline.
III. Transformants containing the Cla I insert are sensitive to both ampicillin and tetracycline.
Which of the statements given above is/are correct?
164.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Cloning a gene of interest at the Hind III site of pBR322 does not yield
recombinants that can be selected based on antibiotic sensitivity.
Reason (R): The Hind III restriction site is located completely outside both the ampicillin and
tetracycline resistance genes in the pBR322 plasmid.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Cloning a gene of interest at the Hind III site of pBR322 does not yield
recombinants that can be selected based on antibiotic sensitivity.
Reason (R): The Hind III restriction site is located completely outside both the ampicillin and
tetracycline resistance genes in the pBR322 plasmid.
In the light of the above statements, choose the correct answer:
165.Consider the following statements regarding the enzyme utilized in chromogenic
alternative selection systems:
I. The enzyme utilized is beta-galactosidase.
II. The enzyme is a proteinaceous endonuclease that cuts genomic DNA to initiate replication.
III. Inserting foreign DNA into the coding sequence of this enzyme inactivates its gene.
IV. The enzyme activity is checked by adding a chromogenic substrate to the bacterial medium.
Which of the statements given above are correct?
alternative selection systems:
I. The enzyme utilized is beta-galactosidase.
II. The enzyme is a proteinaceous endonuclease that cuts genomic DNA to initiate replication.
III. Inserting foreign DNA into the coding sequence of this enzyme inactivates its gene.
IV. The enzyme activity is checked by adding a chromogenic substrate to the bacterial medium.
Which of the statements given above are correct?
166.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In chromogenic screening, colonies with a foreign DNA insert are identified
because they fail to produce the blue colour and remain white.
Reason (R): The presence of the insert causes the insertional inactivation of the beta-
galactosidase gene, preventing the synthesis of a active enzyme.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In chromogenic screening, colonies with a foreign DNA insert are identified
because they fail to produce the blue colour and remain white.
Reason (R): The presence of the insert causes the insertional inactivation of the beta-
galactosidase gene, preventing the synthesis of a active enzyme.
In the light of the above statements, choose the correct answer:
167.Consider the following statements regarding the quantitative distribution of restriction
sites in the E. coli cloning vector pBR322 shown in Figure 9.4:
I. The vector contains exactly one restriction site for each of the seven commonly used
restriction enzymes.
II. There are exactly two restriction sites located inside the ampicillin resistance (ampR) gene
(Pst I and Pvu I).
III. There are exactly two restriction sites located inside the tetracycline resistance (tetR) gene
(BamH I and Sal I).
IV. There are exactly three restriction sites located outside the antibiotic resistance genes (EcoR
I, Cla I, and Hind III).
Which of the statements given above are correct?
sites in the E. coli cloning vector pBR322 shown in Figure 9.4:
I. The vector contains exactly one restriction site for each of the seven commonly used
restriction enzymes.
II. There are exactly two restriction sites located inside the ampicillin resistance (ampR) gene
(Pst I and Pvu I).
III. There are exactly two restriction sites located inside the tetracycline resistance (tetR) gene
(BamH I and Sal I).
IV. There are exactly three restriction sites located outside the antibiotic resistance genes (EcoR
I, Cla I, and Hind III).
Which of the statements given above are correct?
168.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Selectable markers are required in cloning vectors to identify and eliminate non-
transformants.
Reason (R): Transformation is a molecular laboratory procedure through which a piece of
foreign DNA is introduced into a host bacterium.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Selectable markers are required in cloning vectors to identify and eliminate non-
transformants.
Reason (R): Transformation is a molecular laboratory procedure through which a piece of
foreign DNA is introduced into a host bacterium.
In the light of the above statements, choose the correct answer:
169.Consider the following statements regarding the selection of transformants in E. coli
using pBR322:
I. Wild-type E. coli cells are plated on ampicillin plates to select for plasmid-carrying
transformants.
II. Non-transformant cells survive ampicillin plating because they contain chromosomal
resistance genes.
III. The ampicillin resistance gene in pBR322 is disrupted during cloning at the BamHI site.
Which of the statements given above is/are correct?
using pBR322:
I. Wild-type E. coli cells are plated on ampicillin plates to select for plasmid-carrying
transformants.
II. Non-transformant cells survive ampicillin plating because they contain chromosomal
resistance genes.
III. The ampicillin resistance gene in pBR322 is disrupted during cloning at the BamHI site.
Which of the statements given above is/are correct?
170.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Alternative selectable markers were developed specifically to replace the older
dual-antibiotic selection protocols of pBR322.
Reason (R): Selecting recombinants using antibiotic inactivation is a cumbersome procedure
because it requires simultaneous plating on two plates having different antibiotics.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Alternative selectable markers were developed specifically to replace the older
dual-antibiotic selection protocols of pBR322.
Reason (R): Selecting recombinants using antibiotic inactivation is a cumbersome procedure
because it requires simultaneous plating on two plates having different antibiotics.
In the light of the above statements, choose the correct answer:
171.Consider the following statements regarding the color phenotypes in beta-galactosidase
chromogenic selection:
I. The chromogenic substrate is added to the growth agar plate to check for enzyme activity.
II. Non-recombinant colonies produce a highly visible blue colour, indicating an uninterrupted,
functional gene.
III. Recombinant colonies fail to produce any colour and remain white, indicating insertional
inactivation.
IV. Under alternative configurations, recombinants are selected because they produce a bright
yellow color.
Which of the statements given above are correct?
chromogenic selection:
I. The chromogenic substrate is added to the growth agar plate to check for enzyme activity.
II. Non-recombinant colonies produce a highly visible blue colour, indicating an uninterrupted,
functional gene.
III. Recombinant colonies fail to produce any colour and remain white, indicating insertional
inactivation.
IV. Under alternative configurations, recombinants are selected because they produce a bright
yellow color.
Which of the statements given above are correct?
172.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Agrobacterium tumefaciens naturally delivers a piece of DNA known as 'T-DNA'
to transform normal plant cells into a tumor.
Reason (R): This pathogen is highly specific and naturally transforms only cereal monocot crops
like wheat, rice, and maize.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Agrobacterium tumefaciens naturally delivers a piece of DNA known as 'T-DNA'
to transform normal plant cells into a tumor.
Reason (R): This pathogen is highly specific and naturally transforms only cereal monocot crops
like wheat, rice, and maize.
In the light of the above statements, choose the correct answer:
173.Consider the following statements regarding the disarming of eukaryotic pathogen
vectors:
I. The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens is modified to be no longer
pathogenic but still able to deliver genes of interest into plants.
II. Retroviruses in animals are disarmed to ensure they no longer transform normal cells into
cancerous cells.
III. Eukaryotic vectors must retain their wild-type pathogenicity to force host cells to replicate
the foreign insert DNA.
Which of the statements given above are correct?
vectors:
I. The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens is modified to be no longer
pathogenic but still able to deliver genes of interest into plants.
II. Retroviruses in animals are disarmed to ensure they no longer transform normal cells into
cancerous cells.
III. Eukaryotic vectors must retain their wild-type pathogenicity to force host cells to replicate
the foreign insert DNA.
Which of the statements given above are correct?
174.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): DNA is a highly hydrophilic molecule that is completely unable to pass through
cell membranes on its own.
Reason (R): Cell membranes consist of a hydrophobic lipid bilayer that presents an absolute
thermodynamic barrier to charged hydrophilic molecules.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): DNA is a highly hydrophilic molecule that is completely unable to pass through
cell membranes on its own.
Reason (R): Cell membranes consist of a hydrophobic lipid bilayer that presents an absolute
thermodynamic barrier to charged hydrophilic molecules.
In the light of the above statements, choose the correct answer:
175.Consider the following statements regarding the divalent cation competence protocol:
I. Bacterial cells are treated with a specific concentration of a divalent cation like calcium.
II. Calcium treatment increases the efficiency with which DNA enters the bacterium through
pores in its cell wall.
III. The calcium ions actively digest the peptidoglycan wall to open up large permanent gaps.
Which of the statements given above is/are correct?
I. Bacterial cells are treated with a specific concentration of a divalent cation like calcium.
II. Calcium treatment increases the efficiency with which DNA enters the bacterium through
pores in its cell wall.
III. The calcium ions actively digest the peptidoglycan wall to open up large permanent gaps.
Which of the statements given above is/are correct?
176.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Recombinant DNA can be forced into competent cells by incubating them on ice,
followed by placing them briefly at 42°C, and then putting them back on ice.
Reason (R): The brief 42°C heat shock step is performed specifically to permanently denature
host cell wall proteins and open up large, permanent transport gaps.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Recombinant DNA can be forced into competent cells by incubating them on ice,
followed by placing them briefly at 42°C, and then putting them back on ice.
Reason (R): The brief 42°C heat shock step is performed specifically to permanently denature
host cell wall proteins and open up large, permanent transport gaps.
In the light of the above statements, choose the correct answer:
177.Consider the following statements regarding the host cell targets of micro-injection and
biolistics:
I. Micro-injection is highly suitable and primarily restricted to animal hosts.
II. Biolistics (gene gun) is highly suitable and primarily used for plant hosts.
III. In micro-injection, the recombinant DNA is injected directly into the cytoplasm of the target
cell.
IV. In biolistics, the plant cells are bombarded with high velocity micro-particles of gold or
tungsten coated with DNA.
Which of the statements given above are correct?
biolistics:
I. Micro-injection is highly suitable and primarily restricted to animal hosts.
II. Biolistics (gene gun) is highly suitable and primarily used for plant hosts.
III. In micro-injection, the recombinant DNA is injected directly into the cytoplasm of the target
cell.
IV. In biolistics, the plant cells are bombarded with high velocity micro-particles of gold or
tungsten coated with DNA.
Which of the statements given above are correct?
178.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles of gold or tungsten.
Reason (R): These heavy metal micro-particles must be coated with DNA molecules before
bombardment.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles of gold or tungsten.
Reason (R): These heavy metal micro-particles must be coated with DNA molecules before
bombardment.
In the light of the above statements, choose the correct answer:
179.Consider the following statements regarding the disarmed pathogen vector
transformation method:
I. The method uses 'disarmed pathogen' vectors that are no longer capable of causing disease in
the host.
II. When allowed to infect the host cell, the disarmed pathogen transfers the recombinant DNA
into the host.
III. The pathogen vectors are allowed to infect host cells only in highly artificial, cell-free
environments.
Which of the statements given above are correct?
transformation method:
I. The method uses 'disarmed pathogen' vectors that are no longer capable of causing disease in
the host.
II. When allowed to infect the host cell, the disarmed pathogen transfers the recombinant DNA
into the host.
III. The pathogen vectors are allowed to infect host cells only in highly artificial, cell-free
environments.
Which of the statements given above are correct?
180.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Recombinant DNA technology involves several steps in a highly specific
sequential order.
Reason (R): Cloning, host transformation, and product extraction must be executed strictly
after isolation and restriction fragmentation of the source DNA.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Recombinant DNA technology involves several steps in a highly specific
sequential order.
Reason (R): Cloning, host transformation, and product extraction must be executed strictly
after isolation and restriction fragmentation of the source DNA.
In the light of the above statements, choose the correct answer:
181.Consider the following statements regarding the biological properties of Agrobacterium
tumefaciens as a gene transfer agent:
I. It is a natural bacterial pathogen of several dicot plants.
II. It delivers a specific fragment of DNA known as 'T-DNA' into the host genome.
III. The transferred DNA transforms normal plant cells into a tumor.
IV. The plant tumor cells are directed by the bacterial DNA to synthesize specific chemicals
required by the pathogen.
Which of the statements given above are correct?
tumefaciens as a gene transfer agent:
I. It is a natural bacterial pathogen of several dicot plants.
II. It delivers a specific fragment of DNA known as 'T-DNA' into the host genome.
III. The transferred DNA transforms normal plant cells into a tumor.
IV. The plant tumor cells are directed by the bacterial DNA to synthesize specific chemicals
required by the pathogen.
Which of the statements given above are correct?
182.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens is an ideal
cloning vector for plant systems.
Reason (R): The Ti plasmid has been modified into a disarmed cloning vector that is no longer
pathogenic to plants but still retains its DNA-delivery mechanism.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The tumor-inducing (Ti) plasmid of Agrobacterium tumefaciens is an ideal
cloning vector for plant systems.
Reason (R): The Ti plasmid has been modified into a disarmed cloning vector that is no longer
pathogenic to plants but still retains its DNA-delivery mechanism.
In the light of the above statements, choose the correct answer:
183.Consider the following statements regarding the transfer of genes into animal host cells
using viral vectors:
I. Retroviruses in animals have the natural ability to transform normal cells into cancerous
cells.
II. Retroviruses have been disarmed in biotechnology to deliver desirable genes into animal host
cells.
III. Retroviral vectors transfer genes specifically into the mitochondria of host animal cells to
initiate cellular energy expression.
Which of the statements given above are correct?
using viral vectors:
I. Retroviruses in animals have the natural ability to transform normal cells into cancerous
cells.
II. Retroviruses have been disarmed in biotechnology to deliver desirable genes into animal host
cells.
III. Retroviral vectors transfer genes specifically into the mitochondria of host animal cells to
initiate cellular energy expression.
Which of the statements given above are correct?
184.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Geneticists have successfully engineered pathogen-derived cloning vectors to
deliver genes of interest into plant and animal hosts.
Reason (R): Pathogens like bacteria and viruses have known for ages how to deliver genes to
transform eukaryotic host cells and force them to do what they want.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Geneticists have successfully engineered pathogen-derived cloning vectors to
deliver genes of interest into plant and animal hosts.
Reason (R): Pathogens like bacteria and viruses have known for ages how to deliver genes to
transform eukaryotic host cells and force them to do what they want.
In the light of the above statements, choose the correct answer:
185.Consider the following statements regarding the biophysical properties of DNA and host
cell membranes:
I. DNA is a highly hydrophilic molecule.
II. DNA is a highly hydrophobic molecule.
III. Because of its charged polar nature, DNA cannot naturally pass through lipid-rich cell
membranes.
IV. Bacterial host cells must be treated with physical or chemical reagents to be made
'competent' to take up external plasmids.
Which of the statements given above are correct?
cell membranes:
I. DNA is a highly hydrophilic molecule.
II. DNA is a highly hydrophobic molecule.
III. Because of its charged polar nature, DNA cannot naturally pass through lipid-rich cell
membranes.
IV. Bacterial host cells must be treated with physical or chemical reagents to be made
'competent' to take up external plasmids.
Which of the statements given above are correct?
186.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Treating host bacterial cells with a specific concentration of a divalent cation like
calcium increases their competence for DNA uptake.
Reason (R): Calcium treatment increases the efficiency with which DNA enters the bacterium
through pores in its cell wall.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Treating host bacterial cells with a specific concentration of a divalent cation like
calcium increases their competence for DNA uptake.
Reason (R): Calcium treatment increases the efficiency with which DNA enters the bacterium
through pores in its cell wall.
In the light of the above statements, choose the correct answer:
187.Consider the following statements regarding the physical steps of the heat shock protocol
used to force recombinant DNA into competent cells:
I. The cells are incubated with recombinant DNA on ice.
II. The cells are placed briefly at a temperature of exactly 42°C (heat shock).
III. After heat shock, the cells are immediately transferred and kept at a warm recovery
temperature of 37°C before plating.
IV. The final step involves putting the cells back on ice before plating.
Which of the statements given above are correct?
used to force recombinant DNA into competent cells:
I. The cells are incubated with recombinant DNA on ice.
II. The cells are placed briefly at a temperature of exactly 42°C (heat shock).
III. After heat shock, the cells are immediately transferred and kept at a warm recovery
temperature of 37°C before plating.
IV. The final step involves putting the cells back on ice before plating.
Which of the statements given above are correct?
188.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The specific sequence of incubating competent cells on ice, heating them at 42°C,
and returning them to ice is mandatory for bacterial transformation.
Reason (R): This physical temperature cycling protocol destabilizes cell wall components,
thereby enabling the bacteria to take up the recombinant DNA.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The specific sequence of incubating competent cells on ice, heating them at 42°C,
and returning them to ice is mandatory for bacterial transformation.
Reason (R): This physical temperature cycling protocol destabilizes cell wall components,
thereby enabling the bacteria to take up the recombinant DNA.
In the light of the above statements, choose the correct answer:
189.Consider the following statements regarding the micro-injection gene transfer method:
I. Micro-injection is highly suitable and primarily restricted to animal hosts.
II. Recombinant DNA is directly injected into the nucleus of the target cell.
III. Micro-injection is the primary method used to deliver DNA to plant cells containing thick
cell walls.
IV. Splicing of DNA during micro-injection requires helper viruses to integrate the needle-
delivered plasmid.
Which of the statements given above are correct?
I. Micro-injection is highly suitable and primarily restricted to animal hosts.
II. Recombinant DNA is directly injected into the nucleus of the target cell.
III. Micro-injection is the primary method used to deliver DNA to plant cells containing thick
cell walls.
IV. Splicing of DNA during micro-injection requires helper viruses to integrate the needle-
delivered plasmid.
Which of the statements given above are correct?
190.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Micro-injection represents a direct, vector-free method to introduce recombinant
DNA into host animal cells.
Reason (R): In micro-injection, the recombinant DNA is directly injected into the nucleus of an
animal cell using microscopic needles.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Micro-injection represents a direct, vector-free method to introduce recombinant
DNA into host animal cells.
Reason (R): In micro-injection, the recombinant DNA is directly injected into the nucleus of an
animal cell using microscopic needles.
In the light of the above statements, choose the correct answer:
191.Consider the following statements regarding the biolistics or gene gun technique:
I. The method is highly suitable for plant hosts.
II. Plant cells are bombarded with high velocity micro-particles of gold or tungsten.
III. These metal micro-particles must be coated with DNA molecules.
IV. In alternative configurations, micro-particles of platinum or silver are used due to lower
chemical reactivity.
Which of the statements given above are correct?
I. The method is highly suitable for plant hosts.
II. Plant cells are bombarded with high velocity micro-particles of gold or tungsten.
III. These metal micro-particles must be coated with DNA molecules.
IV. In alternative configurations, micro-particles of platinum or silver are used due to lower
chemical reactivity.
Which of the statements given above are correct?
192.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles coated with DNA.
Reason (R): The micro-particles used in biolistics must consist of heavy metals like gold or
tungsten to ensure high momentum and biological inertness.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): In the biolistics or gene gun method, plant cells are bombarded with high-velocity
micro-particles coated with DNA.
Reason (R): The micro-particles used in biolistics must consist of heavy metals like gold or
tungsten to ensure high momentum and biological inertness.
In the light of the above statements, choose the correct answer:
193.Consider the following statements regarding the disarmed pathogen vector
transformation method:
I. The method uses 'disarmed pathogen' vectors that are no longer capable of causing disease in
the host.
II. When allowed to infect the host cell, the disarmed pathogen transfers the recombinant DNA
into the host.
III. The pathogen vectors are allowed to infect host cells only in highly artificial, cell-free
environments.
Which of the statements given above are correct?
transformation method:
I. The method uses 'disarmed pathogen' vectors that are no longer capable of causing disease in
the host.
II. When allowed to infect the host cell, the disarmed pathogen transfers the recombinant DNA
into the host.
III. The pathogen vectors are allowed to infect host cells only in highly artificial, cell-free
environments.
Which of the statements given above are correct?
194.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Disarmed pathogen vectors represent a highly efficient biological method to
deliver recombinant DNA into host cells.
Reason (R): When these disarmed pathogens are allowed to infect host cells, they actively
transfer the recombinant DNA into the host genome.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Disarmed pathogen vectors represent a highly efficient biological method to
deliver recombinant DNA into host cells.
Reason (R): When these disarmed pathogens are allowed to infect host cells, they actively
transfer the recombinant DNA into the host genome.
In the light of the above statements, choose the correct answer:
195.Consider the following statements regarding the molecular state of genomic DNA inside
cells before purification:
I. Nucleic acid is the genetic material of all organisms without exception.
II. In majority of organisms, the genetic material is deoxyribonucleic acid or DNA.
III. The genes are located on long molecules of DNA intertwined with basic proteins such as
histones.
IV. DNA is a single, isolated, free-floating naked molecule in both eukaryotic and prokaryotic
cell nuclei.
Which of the statements given above are correct?
cells before purification:
I. Nucleic acid is the genetic material of all organisms without exception.
II. In majority of organisms, the genetic material is deoxyribonucleic acid or DNA.
III. The genes are located on long molecules of DNA intertwined with basic proteins such as
histones.
IV. DNA is a single, isolated, free-floating naked molecule in both eukaryotic and prokaryotic
cell nuclei.
Which of the statements given above are correct?
196.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Adding chilled ethanol is the final chemical step to isolate DNA in a visible,
physical form from the purified suspension.
Reason (R): DNA is completely insoluble in cold ethanol, which causes it to dehydrate,
aggregate, and precipitate as fine visible threads.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Adding chilled ethanol is the final chemical step to isolate DNA in a visible,
physical form from the purified suspension.
Reason (R): DNA is completely insoluble in cold ethanol, which causes it to dehydrate,
aggregate, and precipitate as fine visible threads.
In the light of the above statements, choose the correct answer:
197.Consider the following statements regarding the enzymatic removal of contaminants
during DNA purification:
I. RNA is removed by treatment with ribonuclease.
II. Proteins are removed by treatment with protease.
III. Polysaccharides and other molecules are removed by treatment with cellulase and lysozyme
respectively.
IV. DNA is purified from RNA and proteins by treating the lysate with DNase to selectively
digest non-target genes.
Which of the statements given above are correct?
during DNA purification:
I. RNA is removed by treatment with ribonuclease.
II. Proteins are removed by treatment with protease.
III. Polysaccharides and other molecules are removed by treatment with cellulase and lysozyme
respectively.
IV. DNA is purified from RNA and proteins by treating the lysate with DNase to selectively
digest non-target genes.
Which of the statements given above are correct?
198.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Agarose gel electrophoresis is employed as a mandatory checkpoint during a
restriction enzyme digestion experiment.
Reason (R): Electrophoresis allows geneticists to monitor the physical progression of the enzyme
digestion by checking the resolution of DNA fragments.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Agarose gel electrophoresis is employed as a mandatory checkpoint during a
restriction enzyme digestion experiment.
Reason (R): Electrophoresis allows geneticists to monitor the physical progression of the enzyme
digestion by checking the resolution of DNA fragments.
In the light of the above statements, choose the correct answer:
199.Consider the following statements regarding the primers utilized in PCR:
I. Primers are small, chemically synthesized oligonucleotides.
II. The primers utilized in PCR are complementary to the regions of target DNA.
III. PCR requires a single, universal primer set consisting of a long double-stranded DNA
template.
IV. In each PCR cycle, two sets of primers are utilized to initiate replication on both strands.
Which of the statements given above are correct?
I. Primers are small, chemically synthesized oligonucleotides.
II. The primers utilized in PCR are complementary to the regions of target DNA.
III. PCR requires a single, universal primer set consisting of a long double-stranded DNA
template.
IV. In each PCR cycle, two sets of primers are utilized to initiate replication on both strands.
Which of the statements given above are correct?
200.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The DNA polymerase enzyme added to a PCR reaction must be isolated from a
thermostable organism like Thermus aquaticus.
Reason (R): Standard cellular DNA polymerases are permanently denatured and inactivated
during the high-temperature denaturation step of PCR.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The DNA polymerase enzyme added to a PCR reaction must be isolated from a
thermostable organism like Thermus aquaticus.
Reason (R): Standard cellular DNA polymerases are permanently denatured and inactivated
during the high-temperature denaturation step of PCR.
In the light of the above statements, choose the correct answer:
201.According to the NCERT diagram in Figure 9.6, what is the exact chronological sequence
of the three steps that make up a single PCR cycle?
I. Primer Annealing.
II. Denaturation.
III. Extension of Primers.
Choose the correct sequential configuration from the options below:
of the three steps that make up a single PCR cycle?
I. Primer Annealing.
II. Denaturation.
III. Extension of Primers.
Choose the correct sequential configuration from the options below:
202.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Repeating the cycles of replication in PCR many times amplifies a single segment
of DNA to approximately 1 billion copies.
Reason (R): This massive 1 billion-fold amplification is theoretically achieved after exactly 30
cycles of the reaction.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Repeating the cycles of replication in PCR many times amplifies a single segment
of DNA to approximately 1 billion copies.
Reason (R): This massive 1 billion-fold amplification is theoretically achieved after exactly 30
cycles of the reaction.
In the light of the above statements, choose the correct answer:
203.Consider the following statements regarding the definition and expression of recombinant
proteins in host systems:
I. Any protein-encoding gene expressed in a heterologous host yields a recombinant protein.
II. A heterologous host represents a species different from the original organism from which the
gene was isolated.
III. Recombinant proteins are structurally and functionally identical to standard cellular
proteins but are synthesized in vitro without host cells.
Which of the statements given above are correct?
proteins in host systems:
I. Any protein-encoding gene expressed in a heterologous host yields a recombinant protein.
II. A heterologous host represents a species different from the original organism from which the
gene was isolated.
III. Recombinant proteins are structurally and functionally identical to standard cellular
proteins but are synthesized in vitro without host cells.
Which of the statements given above are correct?
204.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Small-volume laboratory flask cultures cannot yield commercially appreciable
quantities of recombinant products.
Reason (R): Industrial production requires the development of bioreactors to process very large
volumes of culture ranging from 100 to 1000 litres.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Small-volume laboratory flask cultures cannot yield commercially appreciable
quantities of recombinant products.
Reason (R): Industrial production requires the development of bioreactors to process very large
volumes of culture ranging from 100 to 1000 litres.
In the light of the above statements, choose the correct answer:
205.According to the NCERT text, which of the following represents the complete, verbatim
list of the six growth conditions optimized and controlled inside industrial bioreactors?
I. Temperature and pH.
II. Substrate and Salts.
III. Vitamins and Oxygen.
IV. Pressure and Light intensity.
Choose the correct option containing ONLY correct environmental parameters:
list of the six growth conditions optimized and controlled inside industrial bioreactors?
I. Temperature and pH.
II. Substrate and Salts.
III. Vitamins and Oxygen.
IV. Pressure and Light intensity.
Choose the correct option containing ONLY correct environmental parameters:
206.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Stirred-tank bioreactors are cylindrical or have a curved base.
Reason (R): The cylindrical body or curved base facilitates the mixing of the reactor contents.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Stirred-tank bioreactors are cylindrical or have a curved base.
Reason (R): The cylindrical body or curved base facilitates the mixing of the reactor contents.
In the light of the above statements, choose the correct answer:
207.Consider the following statements regarding the two types of stirred-tank bioreactors
shown in Figure 9.7:
I. The simple stirred-tank bioreactor uses a flat stirrer to mix contents and distribute oxygen.
II. In the sparged stirred-tank bioreactor, sterile air bubbles are sparged through the reactor to
increase the oxygen transfer area.
III. The simple stirred-tank reactor is sparged, whereas the sparged stirred-tank reactor is
unsparged and relies strictly on surface aeration.
IV. Sparging dramatically increases the surface area for oxygen transfer inside the sparged
stirred-tank reactor.
Which of the statements given above are correct?
shown in Figure 9.7:
I. The simple stirred-tank bioreactor uses a flat stirrer to mix contents and distribute oxygen.
II. In the sparged stirred-tank bioreactor, sterile air bubbles are sparged through the reactor to
increase the oxygen transfer area.
III. The simple stirred-tank reactor is sparged, whereas the sparged stirred-tank reactor is
unsparged and relies strictly on surface aeration.
IV. Sparging dramatically increases the surface area for oxygen transfer inside the sparged
stirred-tank reactor.
Which of the statements given above are correct?
208.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Industrial bioreactors are equipped with sampling ports to withdraw small
volumes of culture periodically.
Reason (R): Sampling ports are mandatory to monitor host cell viability, check for
contamination, and trace target protein concentration during the biosynthetic stage.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Industrial bioreactors are equipped with sampling ports to withdraw small
volumes of culture periodically.
Reason (R): Sampling ports are mandatory to monitor host cell viability, check for
contamination, and trace target protein concentration during the biosynthetic stage.
In the light of the above statements, choose the correct answer:
209.According to the NCERT text, which of the following represents the complete, verbatim
list of the five auxiliary systems (excluding sampling ports) present in an industrial stirred-tank
bioreactor?
I. An agitator system and an oxygen delivery system.
II. A foam control system.
III. A temperature control system and a pH control system.
IV. A pressure exhaust system and a light filtration system.
Choose the correct option containing ONLY correct auxiliary systems:
list of the five auxiliary systems (excluding sampling ports) present in an industrial stirred-tank
bioreactor?
I. An agitator system and an oxygen delivery system.
II. A foam control system.
III. A temperature control system and a pH control system.
IV. A pressure exhaust system and a light filtration system.
Choose the correct option containing ONLY correct auxiliary systems:
210.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): After completion of the biosynthetic stage, the product must undergo a series of
processes collectively referred to as downstream processing before marketing.
Reason (R): Downstream processing consists primarily of separation and purification steps to
isolate the active product in pure form.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): After completion of the biosynthetic stage, the product must undergo a series of
processes collectively referred to as downstream processing before marketing.
Reason (R): Downstream processing consists primarily of separation and purification steps to
isolate the active product in pure form.
In the light of the above statements, choose the correct answer:
211.Consider the following statements regarding the enzymatic treatment used to break open
cells for DNA isolation:
I. Bacterial cells are treated with lysozyme to digest their peptidoglycan wall.
II. Plant cells are treated with cellulase to break down their cellulose cell wall.
III. Fungal cells are treated with chitinase to degrade their chitinous cell wall.
IV. Animal tissues are treated with pectinase to dissolve their thick intracellular junctions.
Which of the statements given above are correct?
cells for DNA isolation:
I. Bacterial cells are treated with lysozyme to digest their peptidoglycan wall.
II. Plant cells are treated with cellulase to break down their cellulose cell wall.
III. Fungal cells are treated with chitinase to degrade their chitinous cell wall.
IV. Animal tissues are treated with pectinase to dissolve their thick intracellular junctions.
Which of the statements given above are correct?
212.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Purified eukaryotic genomic DNA can only be cut effectively by restriction
endonucleases after treatment with proteases.
Reason (R): Eukaryotic genes are located on long molecules of DNA that are tightly intertwined
with basic proteins called histones.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Purified eukaryotic genomic DNA can only be cut effectively by restriction
endonucleases after treatment with proteases.
Reason (R): Eukaryotic genes are located on long molecules of DNA that are tightly intertwined
with basic proteins called histones.
In the light of the above statements, choose the correct answer:
213.Consider the following statements regarding the precipitation and collection of purified
DNA in genetic engineering:
I. Purified DNA ultimately precipitates out after the addition of chilled ethanol.
II. The precipitated DNA can be seen as a collection of fine threads in the suspension.
III. The separated DNA is physically removed from the suspension using a process called
spooling.
IV. The precipitated DNA is collected by high-speed filtration through a cellulose membrane.
Which of the statements given above are correct?
DNA in genetic engineering:
I. Purified DNA ultimately precipitates out after the addition of chilled ethanol.
II. The precipitated DNA can be seen as a collection of fine threads in the suspension.
III. The separated DNA is physically removed from the suspension using a process called
spooling.
IV. The precipitated DNA is collected by high-speed filtration through a cellulose membrane.
Which of the statements given above are correct?
214.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Agarose gel electrophoresis is routinely employed during a restriction enzyme
digestion experiment.
Reason (R): DNA is a negatively charged molecule, hence it moves towards the positive electrode
(anode) under an electric field.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Agarose gel electrophoresis is routinely employed during a restriction enzyme
digestion experiment.
Reason (R): DNA is a negatively charged molecule, hence it moves towards the positive electrode
(anode) under an electric field.
In the light of the above statements, choose the correct answer:
215.Consider the following statements regarding the molecular steps in preparing
recombinant DNA:\n\nI. Source DNA and vector DNA must be cut with different restriction
enzymes to prevent self-ligation.\nII. The cut out 'gene of interest' from the source DNA and the
cut vector with space are mixed together.\nIII. The enzyme DNA ligase is added to the mixture
to join the ends of the molecules.\nIV. The joining process results in a combination of circular
autonomously replicating recombinant DNA.\n\nWhich of the statements given above are
correct?
recombinant DNA:\n\nI. Source DNA and vector DNA must be cut with different restriction
enzymes to prevent self-ligation.\nII. The cut out 'gene of interest' from the source DNA and the
cut vector with space are mixed together.\nIII. The enzyme DNA ligase is added to the mixture
to join the ends of the molecules.\nIV. The joining process results in a combination of circular
autonomously replicating recombinant DNA.\n\nWhich of the statements given above are
correct?
216.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Polymerase Chain Reaction (PCR) represents an in vitro enzymatic method for
synthesizing multiple copies of a gene of interest.
Reason (R): PCR requires two sets of primers, deoxyribonucleoside triphosphates, and a
thermostable DNA polymerase to replicate template DNA cycles.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Polymerase Chain Reaction (PCR) represents an in vitro enzymatic method for
synthesizing multiple copies of a gene of interest.
Reason (R): PCR requires two sets of primers, deoxyribonucleoside triphosphates, and a
thermostable DNA polymerase to replicate template DNA cycles.
In the light of the above statements, choose the correct answer:
217.Consider the following statements regarding the primers utilized in PCR:
I. Primers are small, chemically synthesized oligonucleotides.
II. The primers are complementary to the regions of the template DNA.
III. PCR requires a single, double-stranded DNA primer to initiate replication at the origin.
IV. Primers provide the free 3′-OH end necessary for DNA polymerase to extend the chain.
Which of the statements given above are correct?
I. Primers are small, chemically synthesized oligonucleotides.
II. The primers are complementary to the regions of the template DNA.
III. PCR requires a single, double-stranded DNA primer to initiate replication at the origin.
IV. Primers provide the free 3′-OH end necessary for DNA polymerase to extend the chain.
Which of the statements given above are correct?
218.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The DNA polymerase used in PCR is isolated from a thermophilic bacterium
called Thermus aquaticus.
Reason (R): This polymerase remains thermostable and active during the high temperature-
induced denaturation of double-stranded DNA.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The DNA polymerase used in PCR is isolated from a thermophilic bacterium
called Thermus aquaticus.
Reason (R): This polymerase remains thermostable and active during the high temperature-
induced denaturation of double-stranded DNA.
In the light of the above statements, choose the correct answer:
219.Consider the following statements regarding the quantitative aspects of PCR
amplification cycles:\n\nI. If the process of DNA replication is repeated many times, the DNA
segment can be amplified to approximately billion times.\nII. To achieve a billion-fold
amplification, the PCR process requires exactly 30 repeated cycles.\nIII. Stating that a PCR
cycle is repeated 3 times means the template has been amplified three-fold.\nIV. The
thermostable Taq polymerase extends the primers using the nucleotides provided in the
reaction.\n\nWhich of the statements given above are correct?
amplification cycles:\n\nI. If the process of DNA replication is repeated many times, the DNA
segment can be amplified to approximately billion times.\nII. To achieve a billion-fold
amplification, the PCR process requires exactly 30 repeated cycles.\nIII. Stating that a PCR
cycle is repeated 3 times means the template has been amplified three-fold.\nIV. The
thermostable Taq polymerase extends the primers using the nucleotides provided in the
reaction.\n\nWhich of the statements given above are correct?
220.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Spreading the transformed E. coli mixture on ampicillin-containing agar plates
allows the selection of transformed cells.
Reason (R): Non-transformant E. coli cells lack the ampicillin resistance gene and are killed in
the presence of ampicillin, whereas transformants survive and grow.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Spreading the transformed E. coli mixture on ampicillin-containing agar plates
allows the selection of transformed cells.
Reason (R): Non-transformant E. coli cells lack the ampicillin resistance gene and are killed in
the presence of ampicillin, whereas transformants survive and grow.
In the light of the above statements, choose the correct answer:
221.Consider the following statements regarding the expression of cloned foreign genes in
host cells:
I. The ultimate aim of almost all recombinant technologies is to produce a desirable protein.
II. If any protein-encoding gene is expressed in a heterologous host, it is called a recombinant
protein.
III. The cells harbouring cloned genes of interest can be grown on a small scale in the laboratory
to extract and purify the protein.
IV. Recombinant protein expression occurs spontaneously under any physiological conditions
without needing optimization.
Which of the statements given above are correct?
host cells:
I. The ultimate aim of almost all recombinant technologies is to produce a desirable protein.
II. If any protein-encoding gene is expressed in a heterologous host, it is called a recombinant
protein.
III. The cells harbouring cloned genes of interest can be grown on a small scale in the laboratory
to extract and purify the protein.
IV. Recombinant protein expression occurs spontaneously under any physiological conditions
without needing optimization.
Which of the statements given above are correct?
222.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): Using a continuous culture system produces a much larger biomass and higher
yields of desired protein compared to small-scale batch systems.
Reason (R): In a continuous culture, used medium is drained out from one side while fresh
medium is added from the other to maintain cells in their physiologically most active log phase.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): Using a continuous culture system produces a much larger biomass and higher
yields of desired protein compared to small-scale batch systems.
Reason (R): In a continuous culture, used medium is drained out from one side while fresh
medium is added from the other to maintain cells in their physiologically most active log phase.
In the light of the above statements, choose the correct answer:
223.Consider the following statements regarding the engineering scale and role of bioreactors
in biotechnology:\n\nI. To produce recombinant products in large quantities, processing large
volumes of 100 to 1000 litres is required.\nII. Bioreactors can be thought of as vessels in which
raw materials are biologically converted into specific products using living cells or individual
enzymes.\nIII. Bioreactor conversion can utilize microbial, plant, animal, or human cells.\nIV.
Industrial bioreactor scale is described in the text as ranging from 10,000 to 100,000 litres to
minimize production costs.\n\nWhich of the statements given above are correct?
in biotechnology:\n\nI. To produce recombinant products in large quantities, processing large
volumes of 100 to 1000 litres is required.\nII. Bioreactors can be thought of as vessels in which
raw materials are biologically converted into specific products using living cells or individual
enzymes.\nIII. Bioreactor conversion can utilize microbial, plant, animal, or human cells.\nIV.
Industrial bioreactor scale is described in the text as ranging from 10,000 to 100,000 litres to
minimize production costs.\n\nWhich of the statements given above are correct?
224.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): A bioreactor must provide highly controlled and optimized temperature, pH,
substrate, salts, vitamins, and oxygen conditions.
Reason (R): Providing optimal growth conditions is essential to achieve the maximum biological
conversion of raw materials into the desired recombinant product.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): A bioreactor must provide highly controlled and optimized temperature, pH,
substrate, salts, vitamins, and oxygen conditions.
Reason (R): Providing optimal growth conditions is essential to achieve the maximum biological
conversion of raw materials into the desired recombinant product.
In the light of the above statements, choose the correct answer:
225.Consider the following statements regarding the physical shape and structural
components of a stirring type bioreactor:\n\nI. The most commonly used bioreactors are of the
stirring type.\nII. A stirred-tank reactor is usually cylindrical or with a curved base.\nIII. The
curved base geometry is designed to facilitate the mixing of the reactor contents.\nIV. Flat-
bottomed bioreactors are preferred for plant cell cultures to prevent cell shear stress.\n\nWhich
of the statements given above are correct?
components of a stirring type bioreactor:\n\nI. The most commonly used bioreactors are of the
stirring type.\nII. A stirred-tank reactor is usually cylindrical or with a curved base.\nIII. The
curved base geometry is designed to facilitate the mixing of the reactor contents.\nIV. Flat-
bottomed bioreactors are preferred for plant cell cultures to prevent cell shear stress.\n\nWhich
of the statements given above are correct?
226.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):
Assertion (A): The stirrer in a simple stirred-tank bioreactor is superior to simple shaking flasks
for large-scale cell propagation.
Reason (R): The stirrer facilitates even mixing and oxygen availability throughout the entire
volume of the bioreactor.
In the light of the above statements, choose the correct answer:
as Reason (R):
Assertion (A): The stirrer in a simple stirred-tank bioreactor is superior to simple shaking flasks
for large-scale cell propagation.
Reason (R): The stirrer facilitates even mixing and oxygen availability throughout the entire
volume of the bioreactor.
In the light of the above statements, choose the correct answer:
227.Consider the following statements regarding the auxiliary control systems built into
industrial stirred-tank bioreactors:\n\nI. The bioreactor possesses an agitator system and an
oxygen delivery system.\nII. It contains a foam control system, a temperature control system,
and a pH control system.\nIII. It has sampling ports so that small volumes of the culture can be
withdrawn periodically.\nIV. The text lists sampling ports as the sixth internal auxiliary control
system of the bioreactor.\n\nWhich of the statements given above are correct?
industrial stirred-tank bioreactors:\n\nI. The bioreactor possesses an agitator system and an
oxygen delivery system.\nII. It contains a foam control system, a temperature control system,
and a pH control system.\nIII. It has sampling ports so that small volumes of the culture can be
withdrawn periodically.\nIV. The text lists sampling ports as the sixth internal auxiliary control
system of the bioreactor.\n\nWhich of the statements given above are correct?
228.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): Downstream processing is a mandatory phase carried out after
the completion of the biosynthetic stage in biotechnology.\nReason (R): The isolated crude
recombinant product must undergo separation and purification before it is ready for marketing
as a finished active product.\n\nIn the light of the above statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): Downstream processing is a mandatory phase carried out after
the completion of the biosynthetic stage in biotechnology.\nReason (R): The isolated crude
recombinant product must undergo separation and purification before it is ready for marketing
as a finished active product.\n\nIn the light of the above statements, choose the correct answer:
229.Consider the following statements regarding the formulation and testing steps in
downstream processing:\n\nI. The purified product must be formulated with suitable
preservatives.\nII. In the case of drugs, the formulated product has to undergo thorough clinical
trials.\nIII. Strict quality control testing is required for each and every biotechnological
product.\nIV. Downstream processing and quality control testing protocols are identical and
standardized for all products to ensure uniformity.\n\nWhich of the statements given above are
correct?
downstream processing:\n\nI. The purified product must be formulated with suitable
preservatives.\nII. In the case of drugs, the formulated product has to undergo thorough clinical
trials.\nIII. Strict quality control testing is required for each and every biotechnological
product.\nIV. Downstream processing and quality control testing protocols are identical and
standardized for all products to ensure uniformity.\n\nWhich of the statements given above are
correct?
230.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): Downstream processing and quality control testing protocols
must be designed and optimized separately for each individual product.\nReason (R): The
chemical nature of the recombinant molecule, its host cell contaminants, and its clinical
administration route vary significantly from product to product.\n\nIn the light of the above
statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): Downstream processing and quality control testing protocols
must be designed and optimized separately for each individual product.\nReason (R): The
chemical nature of the recombinant molecule, its host cell contaminants, and its clinical
administration route vary significantly from product to product.\n\nIn the light of the above
statements, choose the correct answer:
231.Consider the following statements regarding the sequential steps of a single PCR cycle
shown in Figure 9.6:\n\nI. The first step is Denaturation, which uses high temperature to
separate the two strands of DNA.\nII. The second step is Annealing, where two sets of primers
bind to their complementary regions on the single-stranded templates.\nIII. The third step is
Extension, where Taq DNA polymerase extends the primers in the 5′ to 3′ direction using
nucleotides.\nIV. The chronological order of steps in a cycle is: Annealing → Denaturation →
Extension.\n\nWhich of the statements given above are correct?
shown in Figure 9.6:\n\nI. The first step is Denaturation, which uses high temperature to
separate the two strands of DNA.\nII. The second step is Annealing, where two sets of primers
bind to their complementary regions on the single-stranded templates.\nIII. The third step is
Extension, where Taq DNA polymerase extends the primers in the 5′ to 3′ direction using
nucleotides.\nIV. The chronological order of steps in a cycle is: Annealing → Denaturation →
Extension.\n\nWhich of the statements given above are correct?
232.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): The thermostable DNA polymerase enzyme used in PCR is
isolated from a bacterium called Thermus aquaticus.\nReason (R): Thermus aquaticus is a
thermophilic eukaryotic fungus that naturally thrives in hot sulfur springs and deep
hydrothermal vents.\n\nIn the light of the above statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): The thermostable DNA polymerase enzyme used in PCR is
isolated from a bacterium called Thermus aquaticus.\nReason (R): Thermus aquaticus is a
thermophilic eukaryotic fungus that naturally thrives in hot sulfur springs and deep
hydrothermal vents.\n\nIn the light of the above statements, choose the correct answer:
233.Consider the following statements regarding the cell growth kinetics inside a continuous
culture system:\n\nI. Cells are multiplied in a system where fresh medium is continuously added
while used medium is drained out.\nII. The continuous inflow/outflow maintains the cells in
their physiologically most active log/exponential phase.\nIII. The continuous culture method is
designed to keep cells in their physiologically inactive lag phase to prevent mutation
accumulation.\nIV. Maintaining the cells in the active log phase produces a larger biomass and
higher yields of recombinant protein.\n\nWhich of the statements given above are correct?
culture system:\n\nI. Cells are multiplied in a system where fresh medium is continuously added
while used medium is drained out.\nII. The continuous inflow/outflow maintains the cells in
their physiologically most active log/exponential phase.\nIII. The continuous culture method is
designed to keep cells in their physiologically inactive lag phase to prevent mutation
accumulation.\nIV. Maintaining the cells in the active log phase produces a larger biomass and
higher yields of recombinant protein.\n\nWhich of the statements given above are correct?
234.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): A sparged stirred-tank bioreactor is characterized by the
presence of sterile air bubbles sparged through the liquid culture.\nReason (R): Sparging sterile
air bubbles increases the surface area for oxygen transfer within the bioreactor.\n\nIn the light
of the above statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): A sparged stirred-tank bioreactor is characterized by the
presence of sterile air bubbles sparged through the liquid culture.\nReason (R): Sparging sterile
air bubbles increases the surface area for oxygen transfer within the bioreactor.\n\nIn the light
of the above statements, choose the correct answer:
235.Consider E. coli host cells transformed with a plasmid carrying an ampicillin resistance
gene. Which of the following statements correctly describe the transformation outcomes when
plated on ampicillin-containing agar?\n\nI. Transformed cells have taken up the plasmid and
survive on the ampicillin plate.\nII. Untransformed recipient cells lack the plasmid and die on
the ampicillin plate.\nIII. The ampicillin resistance gene acts as a selectable marker in this
selection step.\nIV. Recombinant transformed cells will die on ampicillin because they carry the
foreign insert.\n\nChoose the correct option:
gene. Which of the following statements correctly describe the transformation outcomes when
plated on ampicillin-containing agar?\n\nI. Transformed cells have taken up the plasmid and
survive on the ampicillin plate.\nII. Untransformed recipient cells lack the plasmid and die on
the ampicillin plate.\nIII. The ampicillin resistance gene acts as a selectable marker in this
selection step.\nIV. Recombinant transformed cells will die on ampicillin because they carry the
foreign insert.\n\nChoose the correct option:
236.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): Treating a crude cell lysate with ribonuclease is a critical step
to isolate pure DNA during the extraction process.\nReason (R): Ribonuclease digests and
eliminates protein contaminants, while protease selectively degrades contaminating RNA
molecules.\n\nIn the light of the above statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): Treating a crude cell lysate with ribonuclease is a critical step
to isolate pure DNA during the extraction process.\nReason (R): Ribonuclease digests and
eliminates protein contaminants, while protease selectively degrades contaminating RNA
molecules.\n\nIn the light of the above statements, choose the correct answer:
237.Consider the following statements regarding the biochemical conversion process in
industrial bioreactors:\n\nI. Bioreactors physically filter and centrifuge raw materials into
purified chemical isomers.\nII. Bioreactors biologically convert raw materials into specific
products, individual enzymes, etc.\nIII. The biological conversion inside a bioreactor is carried
out using microbial, plant, animal, or human cells.\nIV. The conversions rely exclusively on
inorganic metallic catalysts to force expression at high temperatures.\n\nWhich of the
statements given above are correct?
industrial bioreactors:\n\nI. Bioreactors physically filter and centrifuge raw materials into
purified chemical isomers.\nII. Bioreactors biologically convert raw materials into specific
products, individual enzymes, etc.\nIII. The biological conversion inside a bioreactor is carried
out using microbial, plant, animal, or human cells.\nIV. The conversions rely exclusively on
inorganic metallic catalysts to force expression at high temperatures.\n\nWhich of the
statements given above are correct?
238.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): The purified genomic DNA precipitated by chilled ethanol can
be removed from the suspension by spooling.\nReason (R): In a suspension, the precipitated
DNA aggregates and separates out as highly visible fine threads.\n\nIn the light of the above
statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): The purified genomic DNA precipitated by chilled ethanol can
be removed from the suspension by spooling.\nReason (R): In a suspension, the precipitated
DNA aggregates and separates out as highly visible fine threads.\n\nIn the light of the above
statements, choose the correct answer:
239.Regarding downstream processing and quality control testing, which of the following
statements is/are CORRECT according to NCERT?\n\nI. Downstream processing includes
separation and purification steps.\nII. Formulated products must undergo thorough clinical
trials as in the case of drugs.\nIII. Downstream processing and quality control testing protocols
are identical and standardized for all products to ensure industrial compliance.\nIV.
Downstream processing and quality control testing vary from product to product.\n\nChoose
the correct option:
statements is/are CORRECT according to NCERT?\n\nI. Downstream processing includes
separation and purification steps.\nII. Formulated products must undergo thorough clinical
trials as in the case of drugs.\nIII. Downstream processing and quality control testing protocols
are identical and standardized for all products to ensure industrial compliance.\nIV.
Downstream processing and quality control testing vary from product to product.\n\nChoose
the correct option:
240.Given below are two statements, one is labelled as Assertion (A) and the other is labelled
as Reason (R):\n\nAssertion (A): Stirred-tank bioreactors are engineered with a curved base
and a mechanical impeller stirrer.\nReason (R): The curved base and stirrer facilitate even
mixing and oxygen availability throughout the entire volume of the bioreactor.\n\nIn the light of
the above statements, choose the correct answer:
as Reason (R):\n\nAssertion (A): Stirred-tank bioreactors are engineered with a curved base
and a mechanical impeller stirrer.\nReason (R): The curved base and stirrer facilitate even
mixing and oxygen availability throughout the entire volume of the bioreactor.\n\nIn the light of
the above statements, choose the correct answer:
Answer Key
12
24
31
42
52
61
74
82
93
103
111
122
133
142
152
161
173
183
191
204
214
224
232
243
252
262
272
283
293
302
313
321
333
343
352
364
373
383
391
401
414
422
431
443
451
463
472
482
492
502
511
521
533
542
554
562
572
584
593
603
614
621
631
641
652
661
672
684
694
702
714
723
732
744
751
763
771
784
794
804
811
824
833
844
852
861
872
881
893
903
912
924
931
941
954
961
971
982
992
1001
1011
1021
1033
1042
1054
1061
1071
1084
1093
1101
1113
1124
1134
1144
1151
1162
1174
1182
1191
1204
1213
1222
1233
1244
1252
1263
1271
1284
1294
1304
1314
1324
1331
1342
1353
1361
1371
1383
1394
1402
1413
1424
1433
1443
1451
1463
1471
1482
1493
1504
1511
1523
1531
1543
1553
1561
1571
1583
1593
1604
1611
1623
1631
1641
1654
1664
1674
1681
1692
1704
1713
1722
1731
1742
1751
1763
1774
1784
1791
1804
1813
1822
1832
1841
1853
1863
1874
1883
1891
1904
1914
1923
1933
1943
1952
1964
1973
1983
1994
2004
2013
2021
2034
2042
2053
2062
2072
2083
2091
2101
2112
2122
2131
2141
2153
2161
2173
2183
2194
2202
2211
2221
2233
2242
2254
2264
2272
2284
2291
2303
2311
2322
2334
2343
2351
2364
2373
2382
2391
2404