Biotech-I NCERT Flashcards
(210 cards)
1
Q
scientist
A
2
Q
Construction of 1st artificial recombinant DNA molecule was accomplished by ______ and ______ in year ______.
A
Stanley Cohen and Herbert Boyer; 1972
3
Q
Biotechnology is:-
A
Biotechnology is a technique of using live organisms or enzymes from organisms to produce products and processes useful to humans.
4
Q
All microbe-mediated processes could also be thought of as a form of biotechnology.
(T/F)
A
True, Making curd, bread, or wine, which are all microbe-mediated processes, could also be thought of as a form of biotechnology.
5
Q
Biotechnology is used in an unrestricted sense today.
(T/F)
A
False,
Biotechnology is used in a restricted sense today.
6
Q
Examples of biotechnology are:-
A
i) in-vitro fertilization leading to a ‘test-tube’ baby
ii) Synthesising a gene and using it
iii) Developing a DNA vaccine
iv) Correcting a defective gene
7
Q
____ has given a definition of biotechnology that encompasses both traditional views and modern molecular biotechnology.
A
European Federation of Biotechnology (EFB)
8
Q
The definition given by EFB is as follows:
A
‘The integration of natural science and organisms, cells, parts theory of, and molecular analogs for products and services.’
9
Q
The two core techniques that enabled birth of modern biotechnology are:-
A
Genetic and Bioprocess engineering
10
Q
Genetic engineering is:-
A
i) To alter the chemistry of genetic material (DNA and RNA)
ii) To introduce these into host organisms
iii) To change the phenotype of host organism.
11
Q
Bioprocess engineering is:-
A
i) For maintenance of sterile (microbial contamination-free) ambiance in chemical engineering processes
ii) To enable growth of only desired microbe/eukaryotic cells in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc.
12
Q
Sexual reproduction may be beneficial to the organism as well as the population. Why?
A
Sexual reproduction provides:-
i) Opportunities for variations
ii) Formulation of unique combinations of genetic setup
13
Q
The type of reproduction which preserves genetic information is:-
A
Asexual reproduction
14
Q
The type of reproduction which permits variation is:-
A
Sexual reproduction
15
Q
Traditional hybridization procedures used in plant and animal breeding lead to a disadvantage:-
A
Inclusion and multiplication of undesirable genes along with the desired genes.
16
Q
Genetic engineering includes:-
i) Creation of _____________.
ii) Use of ___________ and ____________.
A
i) Creation of Recombinant DNA.
ii) Use of gene cloning and gene transfer
17
Q
Genetic Engineering allows us to isolate and introduce only one or a set of desirable genes ______ (with/without) introducing undesirable genes into the target organism.
A
Without introducing undesirable genes into the target organism
18
Q
An alien piece of DNA is not able to multiply itself in the progeny cells of the organism.
Give the reason.
A
When it gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA.
19
Q
The specific DNA sequence of chromosome responsible for initiating DNA replication is:-
A
Origin of replication
20
Q
Conditions for multiplication of alien DNA in host organism:-
A
Alien DNA needs to be a part of a chromosome(s) which has a specific sequence (origin of replication)
21
Q
Replication and multiplication of Alien piece of DNA in the host organism is known as:
A
Cloning
22
Q
The process of making multiple identical copies of any template DNA is called:-
A
Cloning
23
Q
In ______ year, first recombinant DNA was constructed by __________ and _________
A
1972; Stanley Cohen; Herbert Boyer
24
Q
An autonomously replicating circular extra-chromosomal DNA of bacteria is called:-
A
Plasmid
25
First recombinant DNA was constructed by linking ______ with ______.
by linking
i) Gene encoding antibiotic resistance
with
ii) Native plasmid of Salmonella typhimurium
26
What did Stanley Cohen and Herbert Boyer do?
They isolate the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance
27
The cutting of DNA at specific locations is done with the help of:-
restriction enzymes
28
Restriction enzymes are also known as:-
Molecular scissors
29
In genetic engineering, the cut piece of DNA at specific locations was further linked with ________.
Plasmid DNA
30
Plasmid DNA act as ________ to transfer an alien piece of DNA linked to it into a host organism.
vector
31
Mosquito acts as ______ to transfer the malarial parasite into the human body.
insect vector
32
Linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme __________
DNA ligase
33
______ acts on cut DNA molecules and joins their ends.
DNA ligase
34
DNA Ligase makes a new combination of circular, autonomously replicating DNA created in vitro, which is known as ______.
Recombinant DNA.
35
Replication of recombinant DNA in host is accomplished by using which enzyme of host?
DNA polymerase
36
Escherichia coli is a bacterium closely related to ______.
Salmonella
37
The ability to multiply copies of an antibiotic-resistance gene in
E. coli is called ______.
Cloning of antibiotic-resistance gene in E. coli.
38
Three basic steps in genetically
modifying an organism -
(i) identification of DNA with desirable genes;
(ii) introduction of the identified DNA into the host;
(iii) maintenance of introduced DNA in the host and transfer of the DNA to its progeny.
39
Key tools of genetic engineering are:-
Restriction enzymes, polymerase enzymes, ligase, vector, and host organism
40
In ______ year, the two enzymes responsible for restricting the growth of bacteriophage in ______ were isolated.
Functions of these two enzymes:-
1963; Escherichia coli
One of these added methyl groups to DNA, while the other (called restriction endonuclease) cut DNA.
41
The first restriction endonuclease, whose functioning depended on a specific DNA nucleotide sequence, was known as _______.
Hind II
42
Hind II always cut DNA molecules at a particular point by recognizing a recognition sequence of ______ base pairs.
Six base pairs
43
The specific base sequence recognised by restriction endonuclease to cut the DNA is called:-
recognition sequence
44
Besides Hind II, today we know ______ number of restriction enzymes that are isolated from ______ number of strains of bacteria each of which recognizes different recognition sequences.
more than 900 restriction enzymes; over 230 strains of bacteria
45
EcoRI comes from which Restriction enzyme
Restriction enzyme Escherichia coli RY 13
46
Convention for naming:-
E -
co -
R -
I -
1st letter (E) - Genus
2nd two letters (co) - Species of the prokaryotic cell from which they were isolated
R - Name of strain
I - Order in which enzymes were isolated from that strain of bacteria
47
The second two letters while naming an enzyme comes from the species of the ____________ from which they were isolated.
prokaryotic cell
48
While naming restriction enzymes, the order in which the enzyme was isolated from the strain of bacteria is indicated by:-
roman numbers
49
Restriction enzymes belong to which class of enzymes?
nucleases
50
Nucleases are of two kinds:-
Exonucleases and Endonucleases.
51
Nucleases that remove nucleotides from the ends of DNA are called:-
exonucleases
52
Nucleases that make cuts at specific positions within DNA are called:-
endonucleases
53
Restriction enzyme works as:-
i) Inspecting the length of a DNA sequence
ii) Finds its specific recognition sequence
iii) It will bind to the DNA
iv) It will cut each of the two strands of Double-Helix at specific points in their Sugar-Phosphate backbones.
54
The sequence recognized by restriction endonuclease to cut the strand in DNA is:-
palindromic nucleotide sequence
55
Steps in formation of recombinant DNA by action of restriction endonuclease enzyme(EcoRI) are:-
i) Action of Restriction enzyme
ii) The enzyme cuts both Vector DNA strands at the same site
iii) EcoRI cuts the Foreign DNA between bases G and A only when the sequence GAATTC is present in the DNA
iv) DNA fragments join at sticky ends
v) Recombinant DNA made
56
The sequence of base pairs that reads same on the two strands when orientation of reading is kept same is called:-
Palindrome
57
Restriction enzymes cut the strand of DNA at the center of palindrome sites.
(T/F)
False, Restriction enzymes cut the strand of DNA a little away from the centre of the palindrome sites.
58
Restriction enzymes cut the strand of DNA between the different two bases on the opposite strands.
(T/F)
False, Restriction enzymes cut the strand of DNA between the same two bases on the opposite strands.
59
The overhanging stretches or single-stranded portion left at the ends by restriction enzymes are called:-
sticky ends
60
Sticky ends forms ______ with their complementary cut counterparts.
hydrogen bonds
61
The stickiness of sticky ends facilitates the action of enzyme ___________ on them.
DNA ligase
62
Why Restriction endonucleases are used?
Restriction endonucleases are used in genetic engineering to form ‘recombinant’ molecules of DNA, which are composed of DNA from different sources/genomes.
63
Steps for recombinant DNA technology:-
i) Same restriction enzyme cutting both foreign DNA and Vector DNA (plasmid) at a specific point
ii) Ligases join foreign DNA to Plasmid
iii) Transformation of Recombinant DNA molecule into E.coli
iv) Cells divide into Cloning Host
64
The cutting of DNA by restriction endonucleases results in the ____________ of DNA.
fragments
65
When cut by the same restriction enzyme, the resultant DNA fragments
have ______ (same/different) kind of ‘sticky-ends,' joining together
(end-to-end) using DNA ligases
same kind of ‘sticky-ends’
66
Source DNA and ______ need to be cut with the same restriction enzyme in order to create a recombinant molecule.
vector
67
The fragments of DNA can be separated by a technique known as:-
Gel electrophoresis
68
DNA fragments are ______ charged molecules.
Negatively charged
69
DNA fragments can be separated by forcing them to move towards the ______ (cathode/anode) under an electric field through a medium/matrix.
move towards the anode
70
Most commonly used gel matrix for electrophoresis is:-
agarose
71
Agarose is a ______ polymer extracted from ______.
natural; seaweeds
72
During separation, agarose gel provides __________ effect.
sieving effect
73
DNA fragments in agarose gel separate through the sieving effect according to their:-
size
74
DNA fragments that move are known as ______, and that don't move are known as ______.
move - digested fragments
don't move - undigested fragments
75
The ______ (larger/smaller) size fragment moves farther.
smaller
76
DNA samples are loaded at the ______ (cathode/anode).
Reason.
Cathode,
DNA carries a negative charge; in the presence of an electric field, it migrates toward a positive electrode(anode). Therefore, DNA samples are loaded at the cathode(negative electrode).
77
You cannot see pure DNA fragments in the ________ light and without staining.
Visible
78
A compound used to visualize separated DNA fragments (after staining) in agarose gel is:-
ethidium bromide
79
Ethidium bromide-stained DNA can be seen under exposure to:-
UV light/radiation
80
______ colored bands of DNA in ethidium bromide-stained gel exposed to UV light.
Bright orange colored
81
The process of cutting out and extracting separated bands of DNA from gel is called:-
Elution
82
After Elution, purified DNA fragments are used in constructing ______ by joining them with ______.
recombinant DNA; cloning vectors
83
Plasmids and Bacteriophages have the ability to replicate within bacterial cells dependent on the control of chromosomal DNA.
(T/F)
False, this ability to replicate is independent of the control of chromosomal DNA.
84
Bacteriophages have very _______ copy numbers of their genome within bacterial cells.
high
85
Why do Bacteriophages have very high copy numbers?
Because Bacteriophages are present in high numbers per cell.
86
Copy number of plasmids:
Some plasmids may have only one or two copies per cell, whereas others may have 15-100 copies per cell. Their numbers can go even higher.
87
If we are able to link an alien piece of DNA with bacteriophage, we can multiply its numbers equal to the copy number of the bacteriophage.
(T/F)
True
88
If we are able to link an alien piece of DNA with plasmid DNA, we can multiply its numbers equal to the copy number of plasmid DNA.
(T/F)
True
89
Vectors help in:-
i) Easy linking of foreign DNA
ii) Selection of recombinants
from non-recombinants.
90
Features required to facilitate cloning into a vector are:-
(i) Origin of replication (ori)
(ii) Selectable marker
(iii) Cloning sites
(iv) Vectors for cloning genes in plants and animals
91
The sequence from where replication starts is called:-
Origin of replication (ori)
92
Any piece of DNA when linked to which sequence can be made to replicate within the host cells.
ori sequence
93
ori sequence is responsible for:-
For controlling the copy number of the linked DNA
94
What should one do if one wants to recover many copies of the target DNA?
Target DNA should be cloned in a vector whose origin supports a high copy number.
95
In addition to ‘ori’, vector requires a selectable marker which helps in:-
i) Distinguish recombinant cells from non-recombinant cells.
ii) Identify and eliminate non-transformants and selectively permit the transformants' growth.
96
The process through which a piece of DNA is introduced in a host bacterium is called:-
Transformation
97
What are transformants?
Transformants are cell that has taken the additional genetic material (recombinant/non-recombinant).
98
What are recombinants?
Recombinants are the cells that have taken up the Gene of Interest (genetically engineered genetic material).
99
2 types of Selectable markers are:-
i) Genes encoding resistance to antibiotics
ii) Lac Z gene for B- galactosidase enzyme (produce color in the presence of a chromogenic substrate)
100
Name some antibiotic genes used as a selectable marker for E. coli.
Ampicillin, chloramphenicol, tetracycline, kanamycin, etc.
101
The normal E. coli cells do not carry resistance against any antibiotics.
(T/F)
True
102
Cloning sites are ______ sequence with restriction site of ______ nucleotides present in the selectable marker.
Palindromic sequences; 4-8 nucleotides
103
In order to link the alien DNA, the vector needs to have very few, preferably ______, recognition sites for the commonly used restriction enzymes.
Single
104
Presence of more than one _________ within the vector will generate several fragments, which will complicate gene cloning.
recognition sites
105
During cloning, the ligation of alien DNA is carried out at a restriction site present in ____________.
antibiotic resistance gene or Lac - Z gene
106
pBR322 stands for:-
p - Plasmid
B - Boliver
R - Rodriquiz
107
How many selectable markers are present in Vector pBR322?
2
108
The two selectable markers in pBR322 are -
Ampicillin ampR and tetracycline tetR
109
pBR322 has total of ______ restriction sites
8;
BamH I, Sal I (tetR)
Pvu I, Pst I (ampR)
EcoR I, Cla I, Hind III
Pvu II (rop)
110
pBR322 has total of ______ restriction sites in selectable marker.
4;
BamH I, Sal I (tetR)
Pvu I, Pst I (ampR)
111
Rop gene codes is for:-
Proteins involved in replication of plasmid
112
Restriction sites in tetR are -
BamH I, Sal I
113
Restriction sites in ampR are -
Pvu I, Pst I
114
Restriction site in rop is -
Pvu II
115
In a vector, one antibiotic resistance gene helps in selecting the ___________, whereas the other antibiotic resistance gene gets 'inactivated due to insertion’ of alien DNA and helps in selection of ___________.
transformants, recombinants
116
Selection of recombinants due to inactivation of antibiotics is a cumbersome procedure because it requires __________ plating on two plates having _______ antibiotics.
simultaneous, different
117
Alternative selectable markers have been developed which differentiate ____________ from ___________ on the basis of their ability to produce ________ in the presence of a chromogenic substrate.
recombinants, non-recombinants, colour
118
An enzyme used as a selectable marker for selection of recombinants from non-recombinants is:-
Beta-galactosidase
119
During cloning, rDNA is inserted within coding sequence of β-galactosidase, thus leading to:-
insertional inactivation
120
In chromogenic selection, DNA is inserted in the coding sequence of _______ enzyme.
β-galactosidase
121
While using insertional inactivation, the colonies which do not produce any colour in presence of chromogenic substrate are identified as:-
Recombinants colonies
122
Non-recombinant colonies appear ________ in presence of chromogenic substrate when subjected to insertional inactivation.
blue
123
We have learned the lesson of transferring genes into plants and animals from __________ and __________.
bacteria, viruses
124
________ is able to deliver a piece of T-DNA.
Agrobacterium tumefaciens
125
Agrobacterium tumefaciens is a pathogen of ______ (monocot/dicot plants).
Dicot
126
T-DNA transforms normal cells to tumor cells.
(T/F)
True
127
______ in animals have the ability to transform normal cells into cancerous cells.
Retrovirus
128
The tumor-inducing (Ti) plasmid of Agrobacterium tumifaciens has now been modified into a cloning vector which is no more _____________ to the plants.
pathogenic
129
Retroviruses have also been __________ and are now used to deliver __________ genes into animal cells.
disarmed, desirable
130
Once a gene or a DNA fragment has been _________ into a suitable vector, it is transferred into a bacterial, plant, or animal host (where it multiplies).
ligated
131
Since DNA is a ___________ molecule, it cannot pass through cell membranes.
hydrophilic
132
In order to force bacteria to take up the plasmid, the bacterial cells must first be made '___________ to take up DNA
competent
133
The cation used to make bacterial cells competent to take up DNA is:-
calcium
134
Host are made competent by treating them with specific concentration of _____ion.
Calcium
135
Calcium increases the _________ with which DNA enters the bacterium through _______ in its cell wall.
efficiency, pores
136
Recombinant DNA is forced into cells by changing temperature. Tell how?
First, cells are incubated on ice, then heat shock is given, and then again incubated on ice.
137
Heat shock is given to bacterial cells at which temperature to make them competent to take up DNA?
42 degree C
138
In ________ (method), recombinant DNA is directly injected into the nucleus of an animal cell.
micro-injection
139
In plants, cells are bombarded with ______ (high/low) velocity microparticles of ____ and ____ coated with DNA in a method known as _____ or _____.
High, gold and tungsten, biolistics or gene gun
140
______________ vectors, which, when allowed to infect the cell, transfer the recombinant DNA into the host.
Disarmed pathogen
141
Process of Recombinant DNA technology involves several steps:
I. Isolation of DNA
II. Fragmentation of DNA by restriction endonucleases
III. Isolation of a desired DNA fragment
IV. Ligation of the DNA fragment into a vector
V. Transferring the recombinant DNA into the host
VI. Culturing the host cells in a medium at large scale
V. Extraction of the desired product.
142
Genetic material of all organisms is:-
nucleic acid
143
In the majority of organisms, the nucleic acid is ___________ or DNA.
deoxyribonucleic acid
144
In order to cut the DNA with restriction enzymes, it needs to be in pure form, free from other ___________.
macro-molecules
145
Since the DNA is enclosed within the ____________, we have to break the cell open to release DNA.
membranes
146
DNA is released along with other macromolecules such as RNA, proteins, ____________, and also ___________.
polysaccharides, lipids
147
To isolate DNA from bacteria, enzyme used to break the cell open is:-
Lysozyme
148
Isolation of DNA from plant cells is done by disintegrating the cell wall using enzyme:-
Cellulase
149
To isolate DNA from fungus, enzyme used to break the cell open is:-
Chitinase
150
Genes are located on long molecules of DNA interwined with proteins such as _____________.
histones
151
During isolation of DNA, DNA is made free from RNA by using enzyme:-
Ribonuclease (RNase)
152
During isolation of DNA, DNA is made free from proteins by using enzyme:-
Proteases
153
Purified DNA ultimately precipitates out after the addition of _________
Chilled Ethanol
154
DNA ultimately precipitates out and can be seen as a collection of _________ in the suspension.
fine threads
155
DNA that separates out can be removed by ____________
Spooling
156
Restriction enzyme digestions are performed by incubating ____________ DNA molecules with the restriction enzyme at the optimal conditions for that __________ enzyme.
purified, specific
157
After restriction digestion, the technique which is employed to check whether the DNA has been digested is:-
Agarose gel electrophoresis
158
_________ is employed to check the progression of a restriction enzyme digestion.
Agarose gel electrophoresis
159
DNA is a negatively charged molecule; hence it moves toward the ________ electrode
positive
160
The ________ of DNA involves several processes.
joining
161
Joining of source DNA and vector DNA is done with the help of enzyme:-
DNA ligase
162
The cut out ‘___________’ from the source DNA, and the cut vector with space are mixed, and ligase is added. This results in the preparation of ___________.
Gene of interest, recombinant DNA
163
PCR stands for:-
Polymerase Chain Reaction
164
The 3 steps of PCR are -
Denaturation, annealing and extension
165
Multiple copies of the gene of interest are synthesized in vitro using two sets of primers in:-
Polymerase Chain Reaction
166
In PCR, the small chemically synthesised oligonucleotides that are complementary to the regions of DNA are called:-
Primers
167
DNA polymerase extends the _________ using nucleotides provided during PCR.
primers
168
DNA polymerase uses __________ as a template in PCR.
genomic DNA
169
If a PCR cycle runs 30 times, it will produce _____ times the initial amount of desired DNA sequence put into the system.
2^(30)
170
If the process of replication of DNA is repeated many times, the segment of DNA can be amplified to approximately ________ times.
billion
171
______ no. of copies of desired genes will be produced after the end of the first five cycles of PCR
6
(you may think that answer should be 2⁵=32,
but on close observation, you will notice that desired DNA sequence does not start to form till the 3rd step)
172
Thermostable DNA polymerase used in PCR is isolated from a bacterium:-
Thermus aquaticus
173
Thermostable DNA polymerase remains active during the high temperature induced __________ of double-stranded DNA.
denaturation
174
The amplified fragment if desired can now be used to ligate with a vector for further __________.
cloning
175
_________ cells, after making them ‘competent’ to receive, take up DNA present in its surrounding.
Recipient
176
Ampicillin resistance gene when used to select transformed cell is called:-
Selectable marker
177
When you insert a piece of alien DNA into a cloning vector and transfer it into a bacterial, plant, or animal cell, the alien DNA gets ___________.
multiplied
178
In almost all recombinant technologies, the ultimate aim is to produce a desirable __________.
protein
179
There is a need for the recombinant DNA to be ___________.
expressed
180
The _________ gene gets expressed under appropriate conditions.
foreign
181
Expression of the target protein can be induced after cloning the ___________ and having optimized the conditions.
gene of interest
182
To induce the expression of the target protein, one has to consider producing it on a ____________.
large scale
183
When a protein-encoding gene is expressed in a heterologous host, it is called:-
Recombinant protein
184
The cells harboring cloned genes of interest may be grown on a ___________ in the laboratory.
small scale
185
The cultures may be used for _________ the desired protein.
extracting
186
The cultures can be purified by using different ___________ techniques.
separation
187
For production of recombinant protein, the type of culture system which produces a large biomass is:-
Continuous culture system
188
In a continuous culture system wherein the ________ medium is drained out from one side while __________ medium is added from the other medium.
used, fresh
189
The purpose of adding a fresh medium in a continuous culture system is to maintain the cells in their physiologically most active _____________ phase.
log/exponential phase
190
____________ cultures cannot yield appreciable quantities of products.
Small volume
191
The vessels in which large volumes of raw materials are biologically converted into specific products, individual enzymes, etc., using microbial plant, animal, or human cells, are called:-
Bioreactors
192
What is the range of volume of culture that can be processed in a bioreactor?
100-1000 litres
193
A bioreactor provides the optimal conditions for achieving the ______.
desired product
194
The optimum growth conditions in a bioreactor include optimum temperature, ___, substrate, _____, _______, and oxygen.
pH, salts, vitamins
195
The most commonly used bioreactors are of ______ type.
Stirring type
196
A stirred-tank reactor is usually ___________ or with a __________ base to facilitate the mixing of the reactor contents.
cylindrical, curved
197
Stirrer in a stirred-tank reactor facilitates even mixing and ______ availability.
Oxygen
198
The purpose of steam in a simple stirred-tank bioreactor is ___________
sterilization
199
Alternatively, air can be __________ through the reactor.
bubbled
200
____________ dramatically increase the oxygen transfer area.
Bubbles
201
Surface area is increased in a bioreactor for _________ transfer.
oxygen
202
The bioreactors have many systems attached to them.
Name them all.
Systems in bioreactors
I. Agitator system
II. Oxygen delivery system
III. Foam control system
IV. Temperature control system
V. pH control system
VI. Sampling ports
203
A bioreactor has sampling ports so that small volumes of the culture can be ___________ periodically.
withdrawn
204
The process of Downstream processing involves ______ and ______.
Separation; purification
205
After completion of the ___________ stage, the product has to be subjected to a series of processes before it is ready for marketing as a ____________.
Biosynthetic, finished product
206
______ and ______ are collectively referred to as
downstream processing
Separation and purification
207
The product has to be formulated with suitable ______________.
preservatives
208
Formulation has to undergo thorough clinical trials as in the case of _________.
drugs
209
Strict ____________ testing for each product is also required.
quality control
210
The ____________ and ____________ testing vary from product to product.
Downstream processing, quality control
