Past Entrance Paper
Past Entrance Paper
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Question 1 of 74
1. Question
Hind II always cuts DNA molecules at a particular point called recognition sequence and it consists of:
[NEET 2024]CorrectIncorrectHint
Answer (2)
Sol. The correct answer is option (2).
The first restriction endonuclease – Hind II, whose functioning depends on a specific DNA nucleotide sequence was isolated. It was found that Hind II always cut DNA molecules at a particular point by recognising sequence of six base pairs.
Option (1), (3) and (4) are incorrect because they have either more than 6 or less than \(6 \mathrm{bp}\). -
Question 2 of 74
2. Question
What is the fate of a piece of DNA carrying only gene of interest which is transferred into an alien organism?
A. The piece of DNA would be able to multiply itself independently in the progeny cells of the organism.
B. It may get integrated into the genome of the recipient.
C. It may multiply and be inherited along with the host DNA.
D. The alien piece of DNA is not an integral part of chromosome.
E. It shows ability to replicate.Choose the correct answer from the options given below: [NEET 2024]
CorrectIncorrectHint
Answer (3)
Sol. Correct answer is option (3) because
The fate of a piece of DNA carrying only gene of interest which is transferred into an alien organism are:
(B) It may get integrated into the genome of the recipient
(C) It may multiply and be inherited along with the host DNA
\(\Rightarrow\) This piece of DNA would not be able to multiply itself in the progeny cells of the organism but when gets integrated into the genome of the recipient, it may multiply and be inherited along with the host DNA -
Question 3 of 74
3. Question
The “Ti plasmid” of Agrobacterium tumefaciens stands for [NEET 2024]
CorrectIncorrectHint
Answer (3)
Sol. The correct answer is option (3) as Ti plasmid of Agrobacterium tumefaciens is tumor inducing plasmid, containing T-DNA which causes tumor in several dicot plants.
Options (1), (2) and (4) are not correct. -
Question 4 of 74
4. Question
The following diagram showing restriction sites in E. coli cloning vector pBR322. Find the role of ‘ \(X\) ‘ and ‘ \(Y\) genes: [NEET 2024]
CorrectIncorrectHint
Answer (2)
Sol. Correct answer is option (2), because
‘ \(X\) ‘ in the given diagram is ori while ‘ \(Y\) ‘ is rop.
‘ \(X\) ‘ which is ori is responsible for controlling the copy number of the linked DNA and ‘ \(Y\) ‘ which is rop codes for protein involved in the replication of plasmid.
Options (1), (3) and (4) are incorrect as ‘ \(X\) ‘ and ‘ \(Y\) ‘ are not related to these functions. -
Question 5 of 74
5. Question
Main steps in the formation of Recombinant DNA are given below. Arrange these steps in a correct sequence.
A. Insertion of recombinant DNA into the host cell
B. Cutting of DNA at specific location by restriction enzyme
C. Isolation of desired DNA fragment
D. Amplification of gene of interest using PCRChoose the correct answer from the options given below : [NEET 2023]
CorrectIncorrectHint
Answer (1)
Sol. The correct answer is option (1) because recombinant DNA technology involves several steps in specific sequence such as isolation of DNA, fragmentation of DNA by restriction endonucleases, isolation of desired DNA fragment, ligation of the DNA fragment into a vector, transferring the recombinant DNA into the host, culturing the host cells in a medium at large scale and extraction of the desired product. -
Question 6 of 74
6. Question
In gene gun method used to introduce alien DNA into host cells, microparticles of gold and tungsten metal are used. [NEET 2023]
CorrectIncorrectHint
Answer (3)
Sol. Option (3) is the correct answer because in gene gun method, microparticles of tungsten or gold are used. Gold or tungsten are inert in nature so they do not alter the chemical composition of cells. -
Question 7 of 74
7. Question
Which of the following is not a desirable feature of a cloning vector? [NEET 2022]
CorrectIncorrectHint
Answer (4)
Sol. Option (4) is the correct answer. Cloning vectors are the carriers of the desired gene in the host cell. The features desirable in a cloning vector are:-
– Presence of origin of replication
– Presence of marker genes
– Presence of very few, preferably single recognition site for the commonly used restriction enzymes -
Question 8 of 74
8. Question
Given below are two statements:
Statement I:
Restriction endonucleases recognise specific sequence to cut DNA known as palindromic nucleotide sequence.
Statement II:
Restriction endonucleases cut the DNA strand a little away from the centre of the palindromic site.
In the light of the above statements, choose the most appropriate answer from the options given below: [NEET 2022]CorrectIncorrectHint
Answer (1)
Sol. Option)1( is the correct answer because both the statements I and II are correct.
Each restriction endonuclease recognises a specific palindromic nucleotide sequences in the DNA. It will bind to the DNA and cut each of the two strands of double helix at specific points.
Restriction enzymes cut the strand of DNA a little away from the centre of the palindrome site; but between the same two bases on the opposite strands. So both the statements I and II are correct. -
Question 9 of 74
9. Question
Which one of the following statement is not true regarding gel electrophoresis technique? [NEET 2022]
CorrectIncorrectHint
Answer (3)
Sol. Option (3) is the incorrect statement, as bright colored bands of DNA can be observed in the gel when \(\mathrm{Et} \operatorname{Br}\) (Ethidium bromide) treated DNA is exposed to UV light. -
Question 10 of 74
10. Question
The DNA fragments separated on an agarose gel can be visualised after staining with (NEET 2017)
CorrectIncorrectHint
(c) : The separated DNA fragments can be seen only after staining them with a compound known as ethidium bromide ( \(\mathrm{EtBr}\) ) followed by exposure to UV radiation as bright orange coloured bands.
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Question 11 of 74
11. Question
DNA fragments are (NEET 2017)
CorrectIncorrectHint
(a)
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Question 12 of 74
12. Question
A gene whose expression helps to identify transformed cell is known as (NEET 2017)
CorrectIncorrectHint
(d) : Some genes called “selectable markers” help in selecting those host cells which contain the vectors (transformants) and eliminating the non-transformants.
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Question 13 of 74
13. Question
What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis? (NEET 2017)
CorrectIncorrectHint
(a) : Electrophoresis is a technique used for the separation of substances of different ionic properties. Since the DNA fragments are negatively charged molecules, they can be separated by allowing them to move towards the anode. DNA fragments move towards the anode according to their molecules size through the pores of agarose gel. Thus, the smaller fragments move farther away as compared to larger fragments.
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Question 14 of 74
14. Question
The process of separation and purification of expressed protein before marketing is called (NEET 2017)
CorrectIncorrectHint
(a) : After the formation of the product in the bioreactor it undergoes some processes before a finished product is ready for marketing. The process includes separation and purification of products which are collectively called downstream processing.
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Question 15 of 74
15. Question
Stirred-tank bioreactors have been designed for (NEET-II 2016)
CorrectIncorrectHint
(c) : A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. The stirrer facilitates, even mixing and oxygen availability throughout the bioreactor.
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Question 16 of 74
16. Question
A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using
(NEET-II 2016)CorrectIncorrectHint
(d) : Ligase is a class of enzymes that catalyse the formation of covalent bonds using the energy released by the cleavage of ATP. Ligases are important in the synthesis and repair of many biological molecules, including DNA ligase and used in genetic engineering to insert foreign DNA into cloning vectors.
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Question 17 of 74
17. Question
Which of the following is not a component of downstream processing? (NEET-II 2016)
CorrectIncorrectHint
(d) : After the formation of the product in bioreactor, it undergoes through some processes before a finished product to be ready for marketing. Downstream processing includes separation and purification process. The product obtained is subjected to quality control, testing and kept in suitable preservatives.
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Question 18 of 74
18. Question
Which of the following restriction enzymes produces blunt ends? (NEET-II 2016)
CorrectIncorrectHint
(b) : EcoRV is a type II restriction endonuclease isolated from certain strains of E.coli. It creates blunt ends. It recognises the palindromic sequence of 6 bases as shown here:
SalI, XhoI and HindIII restriction enzymes produce sticky ends. -
Question 19 of 74
19. Question
Which of the following is not a feature of the plasmids? (NEET-I 2016)
CorrectIncorrectHint
(b) : Plasmids are extra-chromosomal, selfreplicating, usually circular, double-stranded DNA molecules that serve as vectors which carry foreign DNA segment and replicate inside host cell.
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Question 20 of 74
20. Question
The Taq polymerase enzyme is obtained from (NEET-I 2016)
CorrectIncorrectHint
(c): Taq polymerase, generally used in PCR is isolated from thermophilic bacterium Thermus aquaticus.
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Question 21 of 74
21. Question
Which of the following is a restriction endonuclease? (NEET-I 2016)
CorrectIncorrectHint
(c): Hind II is the first restriction endonuclease. It was isolated from Haemophilus influenzae Rd. It always cut DNA at specific position producing blunt ends. DNase I is an endonuclease that cleaves DNA preferentially at phosphodiester linkages adjacent to a pyrimidine nucleotide non-specially. RNase is a type of nuclease that catalyses the degradation of RNA into smaller components. It can be endoribonuclease or exoribonuclease. A protease is an enzyme that perform proteolysis, i.e., protein catabolism by hydrolysis of the peptide bonds.
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Question 22 of 74
22. Question
Which of the following is not required for any of the techniques of DNA fingerprinting available at present?
(NEET-I 2016)CorrectIncorrectHint
(d) : Any small, functional, freely folded domain in which coordination of one or more zinc ions is required to stabilise its structure is known as zinc finger. The zinc finger domains are widely dispersed in eukaryotic genomes and are actively involved in sequence specific binding to DNA/RNA and contribute in protein-protein recognitions.
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Question 23 of 74
23. Question
The DNA molecule to which the gene of interest is integrated for cloning is called (NEET 2015)
CorrectIncorrectHint
(d) : Vector is a DNA molecule that carries a foreign DNA segment and replicates inside a host cell. The vector DNA and foreign DNA carrying gene of interest are cut by the same restriction endonuclease enzyme to produce complementary sticky ends. With the help of DNA ligase enzyme, the complementary sticky ends of the two DNAs are joined to produce a recombinant DNA (rDNA), which is then introduced into the host cell.
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Question 24 of 74
24. Question
The cutting of DNA at specific locations became possible with the discovery of (NEET 2015)
CorrectIncorrectHint
(c) : Restriction enzymes recognise specific base sequences in a DNA molecule and cut its strands, e.g., EcoRI cuts DNA strands in the base sequence GAATTC.
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Question 25 of 74
25. Question
An analysis of chromosomal DNA using the Southern hybridization technique does not use (NEET 2014)
CorrectIncorrectHint
(d) : PCR is used only for amplification of DNA. It is not directly involved in Southern hybridisation technique.
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Question 26 of 74
26. Question
Which vector can clone only a small fragment of DNA? (NEET 2014)
CorrectIncorrectHint
(c) : Plasmids have been modified to be used as vectors. They can clone DNA fragments of about \(10 \mathrm{kbp}\) size while cosmid can carry upto \(45 \mathrm{kbp}\), YAC can carry upto \(1000-2500 \mathrm{kbp}\) and BAC can carry around \(300-350 \mathrm{Kbp}\) long DNA fragments.
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Question 27 of 74
27. Question
Commonly used vectors for human genome sequencing are (NEET 2014)
CorrectIncorrectHint
(b) : Bacterial artificial chromosome (BAC) vectors are based on natural, extra-chromosomal plasmid of E. coli. BAC vector contains genes for replication and maintenance of the F-factor, a selectable marker and cloning site. These vectors can accommodate upto \(300-350 \mathrm{~kb}\) of foreign DNA and are also being used in genome sequencing project. Yeast artificial chromosome (YAC) vectors are used to clone DNA fragments of more than \(1 \mathrm{Mb}\) in size. Therefore, they have been exploited extensively in mapping the large genomes, e.g., in the Human Genome Project. These vectors contain the telomeric sequence, the centromere and the autonomously replicating sequence from yeast chromosomes.
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Question 28 of 74
28. Question
The colonies of recombinant bacteria appear white in contrast to blue colonies of nonrecombinant bacteria because of
(NEET 2013)CorrectIncorrectHint
(c): The presence of restriction sites within the markers tet \({ }^r\) and \(a m p^r\) of plasmid permits an easy selection for cells transformed with recombinant plasmid. Insertion of the DNA fragment into the plasmid makes antibiotic resistance genes nonfunctional, for example, insertion of the DNA fragment into the plasmid (pBR322) using Pst I or Pvu I makes ampr nonfunctional. Bacterial cells containing such a recombinant \(\mathrm{pBR} 322\) will be unable to grow in the presence of ampicillin, but will grow on tetracycline. This process, however, becomes burdensome because it requires simultaneous plating on two plates having different antibiotics. Thus, alternative selectable marker is developed to differentiate recombinants and nonrecombinants on the basis of their ability to produce colour in the presence of a chromogenic substance. Here, a recombinant DNA is inserted in the coding sequence of an enzyme \(\)\beta\(\)-galactosidase. pUC 18 plasmid contains this gene which allows it to produce \(\)\beta\(\)-galactosidase which degrades certain sugars and produces a blue pigment when exposed to specific substrate analog. If the plasmid in the bacterium does not have an insert, i.e., is nonrecombinant, the presence of chromogenic substrate gives blue coloured colonies. Presence of insert in the plasmid in recombinant bacterium does not produce any colour, such bacterial colonies are marked as recombinant colonies.
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Question 29 of 74
29. Question
DNA fragments generated by the restriction endonucleases in a chemical reaction can be separated by
(NEET 2013)CorrectIncorrectHint
(a):
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Question 30 of 74
30. Question
Which of the following is not correctly matched for the organism and its cell wall degrading enzyme?
(NEET 2013)CorrectIncorrectHint
(a) : Cell wall of algae is made up of cellulose, pectin and mucilage. These substances cannot be degraded by methylase. Methylase is a type of transferase enzyme that transfers a methyl group from a donor to an acceptor.
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Question 31 of 74
31. Question
During the process of isolation of DNA, chilled ethanol is added to (Karnataka NEET 2013)
CorrectIncorrectHint
(a) : Ethanol is much less polar than water. Adding it to the solution disrupts the screening charges exerted by water. The electrical attraction between phosphate and any positive ions \(\left(\mathrm{Na}^{+}\right)\) present in solution becomes strong enough to form a stable ionic bond and DNA precipitates. Ethanol precipitation is a widely used technique to purify, or concentrate nucleic acid.
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Question 32 of 74
32. Question
The given figure is the diagrammatic representation of the \(E\). coli vector \(\mathrm{pBR} 322\). Which one of the given options correctly identifies its certain component(s)?
CorrectIncorrectHint
(d) : In pBR322,
ori-represents site or origin of replication rop-codes for proteins that take part in the replication of plasmid.
Hin d III, Eco RI- recognition sites of restriction endonucleases.
\(a m p^{\mathrm{R}}\) and \(e^{\mathrm{R}}\) – antibiotic resistance genes. -
Question 33 of 74
33. Question
PCR and restriction fragment length polymorphism are the methods for (NEET 2012)
CorrectIncorrectHint
(d) : Polymerase chain reaction (PCR) is used to amplify a small DNA fragment to obtain its large quantity. PCR is very helpful in DNA fingerprinting in such cases where the culprit has to be identified from a very small blood, semen or other cell sample from a crime scene.
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Question 34 of 74
34. Question
A single strand of nucleic acid tagged with a radioactive molecule is called (NEET 2012)
CorrectIncorrectHint
(d) : Probes are single stranded, radiolabelled molecules of nucleic acids with known sequence. The probes having sequence complementary to the gene to be identified are supplied. They bind with the particular gene segment. Radiation imaging identifies the location of that particular segment which bind with probe. Probes are used as identification tool.
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Question 35 of 74
35. Question
Which one is a true statement regarding DNA polymerase used in PCR? (NEET 2012)
CorrectIncorrectHint
(d) : In PCR, Taq polymerase is used which is obtained from Thermus aquaticus bacteria. It is a relatively thermostable enzyme thus used in PCR as during the process the step involving denaturation of DNA strands requires high temperature.
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Question 36 of 74
36. Question
For transformation, micro-particles coated with DNA to be bombarded with gene gun are made up of (NEET 2012)
CorrectIncorrectHint
(d) : A gene or a biolistic particle delivery system, originally designed for plant transformation, is a device for injecting cells with genetic information. The payload is an elemental particle of a heavy metal such as gold or tungsten coated with plasmid DNA. The device is used to transform almost any type of cell including plants, and is not limited to genetic material of the nucleus. It can also transform organelles, including plastids.
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Question 37 of 74
37. Question
Biolistics (gene-gun) is suitable for (NEET 2012)
CorrectIncorrectHint
(b) : Biolistics is a technique for introducing genetic material into living cells, especially plant cells, in which DNA-coated microscopic particles (tungsten or gold particles) are bombarded with a very high velocity into the target cell using a special gun. The microprojectiles, typically \(1 \mathrm{~mm}\) in diameter, are accelerated to high velocity by a specially modified small calibre gun and penetrate the cell walls and plasma membrane with minimal damage. Hence, the novel DNA can be inserted into intact plant cells ultimately transforming it without using a vector.
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Question 38 of 74
38. Question
In genetic engineering, the antibiotics are used (NEET 2012)
CorrectIncorrectHint
(a) : Selectable markers are those genes which help in selecting those host cells which contain vectors (i.e., transformants) and eliminating the non-transformants. The genes encoding resistance to antibiotics such as tetracycline, ampicillin, kanamycin etc., are useful selectable markers for E.coli. Plasmid pBR322 has two resistance genes ampicillin resistance \(\left(a m p^r\right)\) and tetracyclin resistance (tet’) which are considered useful for selectable markers.
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Question 39 of 74
39. Question
The figure below shows three steps \((\mathrm{A}, \mathrm{B}, \mathrm{C})\) of Polymerase Chain Reaction (PCR). Select the option giving correct identification together with what it represents?
CorrectIncorrectHint
(c)
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Question 40 of 74
40. Question
Which one of the following represents a palindromic sequence in DNA?
CorrectIncorrectHint
(a): Palindromes are groups of letters that form the same words when read both forward and backward, e.g., “MALAYALAM”. As against a word-palindrome where the same word is read in both directions, the palindrome in DNA is a sequence of base pairs that reads same on the two strands when orientation of reading is kept the same. For example, the following sequences read the same on the two strands in \(5^{\prime} \rightarrow 3^{\prime}\) direction.
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Question 41 of 74
41. Question
Given below is a sample of a portion of DNA strand giving the base sequence on the opposite strands. What is so special shown in it?
CorrectIncorrectHint
(d)
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Question 42 of 74
42. Question
There is a restriction endonuclease called EcoRI. What does “co” part in it stand for? (NEET 2011)
CorrectIncorrectHint
(d) : The enzyme restriction endonucleas EcoRI is found in the colon bacteria E. coli. So here ‘co’ stands for coli. According to nomenclature of restriction enzyme, the first lette used for the enzyme is the first letter of the genus name (in italics) of the bacterium, then comes the first two letters of its species (also in italics), nex is the strain of the organism. At last is a Romar numeral signifying the order of discovery. Here the enzyme EcoRI was isolated from the bacterium Escherichia coli (co), strain RY13(R) and it was first endonuclease (I) isolated from E.coli.
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Question 43 of 74
43. Question
Agarose extracted from sea weeds is used in (NEET 2011)
CorrectIncorrectHint
(d) : In gel electrophoresis DNA fragment: separate (resolve) according to their size through sieving effect provided by the agarose gel. Agarose is a natural polymer extracted from sea weeds and is commonly used as a matrix.
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Question 44 of 74
44. Question
Which one of the following techniques made it possible to genetically engineer living organisms? (NEET 2011)
CorrectIncorrectHint
(a)
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Question 45 of 74
45. Question
Which one of the following is used as vector for cloning genes into higher organisms? (NEET 2010)
CorrectIncorrectHint
(d) : Retroviruses in animals have the ability to transform normal cells into cancerous cells. We have transformed these pathogens into usefu vectors for delivering genes of interest to humans Retroviruses have been disarmed and are now used to deliver desirable genes into animal cells. So, once a gene or a DNA fragment has been ligated into suitable retroviral vector it is transferred into bacterial, plant or animal host (where it multiplies)
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Question 46 of 74
46. Question
DNA or RNA segment tagged with a radioactive molecule is called (NEET 2010)
CorrectIncorrectHint
(b):
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Question 47 of 74
47. Question
Restriction endonucleases are enzymes which (NEET 2010)
CorrectIncorrectHint
(a) : Restriction endonucleases were found by Arber in 1962 in bacteria. They act as “molecular scissors” or chemical scalpels. They recognize the specific base sequence at palindrome sites in DNA duplex and cut its strands. For example, restriction endonuclease EcoRI found in the colon bacteria E. coli reocgnizes the base sequence GAATTC in DNA duplex and cuts its strands between G and A.
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Question 48 of 74
48. Question
Stirred-tank bioreactors have been designed for (NEET 2010)
CorrectIncorrectHint
(d) : A stirred-tank bioreactor is usually cylindrical or with a curved base to facilitate the mixing of the reaction contents. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor. Alternatively air can be bubbled through the reactor.
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Question 49 of 74
49. Question
Which of the following are used in gene cloning? (NEET 2010)
CorrectIncorrectHint
(d) : Plasmid is a small circular double stranded DNA molecule present in the cytoplasm of the bacterial cell. It can replicate independently of bacterial chromosome. Due to this characteristic of plasmid, it is used as the vector (vectors are for the transferring of a piece of DNA to target gene) in gene cloning.
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Question 50 of 74
50. Question
In genetic engineering, a DNA segment (gene) of interest, is transferred to the host cell through a vector. Consider the following four agents (i-iv) in this regard and select the correct option about which one or more of these can be used as a vector/vectors.
(i) Bacterium
(ii) Plasmid
(iii) Plasmodium
(iv) Bacteriophage (NEET 2010)CorrectIncorrectHint
(d) : Plasmid and bacteriophage are used as vectors in genetic engineering. Plasmid is an autonomously replicating circular extra chromosomal DNA found in bacteria. They can be transferred from cell to cell in a bacterial colony. This characteristic is being used in biotechnology for transferring desirable gene into target gene of the host. Bacteriophage is a bacterial virus which can infect it, quickly multiply within and destroy (lyse) their host (virus) cells. During infection bacteriophages inject their DNA into these cells. The injected DNA selectively replicate and are expressed in the host that results in a multiplication of phages that ultimately burst out of the cell (by lysis). This ability of transferring DNA from the phage genome to specific host during infection process gave scientists the idea that specially designed phage vectors could be used for gene cloning.
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Question 51 of 74
51. Question
Which one of the following is commonly used in transfer of foreign DNA into crop plants? (NEET 2009)
CorrectIncorrectHint
(b) : Agrobacterium tumefaciens has been extensively used in genetic engineering experiments. It is the causative agent of crown gall, an important disease of many commercial crops. This disease has come to be recognized in recent years as being caused by a DNA plasmid (Ti plasmid) carried by bacterium and transferred to the plant cells. Following the discovery of the relationship between crown gall and the Ti plasmid, this plasmid has come to be widely used in plant genetic engineering as a vector in order to inject a novel gene in host plant to form a transgenic plant.
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Question 52 of 74
52. Question
Gel electrophoresis is used for (NEET 2008)
CorrectIncorrectHint
(d)
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Question 53 of 74
53. Question
The linking of antibiotic resistance gene with the plasmid vector became possible with (NEET 2008)
CorrectIncorrectHint
(c) : The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid. The cutting of DNA at specific locations became possible with the discovery of the so-called ‘molecular scissors’ – restriction enzymes. The cut piece of DNA was then linked with the plasmid DNA. This plasmid DNA acts as vector to transfer the piece of DNA attached to it. The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends. This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.
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Question 54 of 74
54. Question
Restriction endonuclease (NEET 2006)
CorrectIncorrectHint
(c)
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Question 55 of 74
55. Question
Two microbes found to be very useful in genetic engineering are (NEET 2006)
CorrectIncorrectHint
(b) : E.coli contains many important standard cloning vectors widely used in gene cloning experiments like pBR322 contains origin of replication (ori). Other cloning vectors like PACYC177, pBR324, PRK 64.6 contain ampicillin resistance gene they are also found in E.coli. Among higher plants, Ti plasmid of Agrobacterium tumefaciens and Ri plasmid of A. rhizogenes is the best known vector.
T-DNA from Ti or Ri plasmid of Agrobacterium is considered to be a very potential vector for cloning experiments with higher plants. -
Question 56 of 74
56. Question
Restriction endonucleases (NEET 2004)
CorrectIncorrectHint
(d) : Restriction endonucleasses are enzymes that digest double stranded DNA following recognition of specific nucleotide sequences. This is achieved by cleaving the two phosphodiester bonds, one within each strand of the DNA duplex. They are found in bacteria and their function in bacteria is to cut up any invading virus as a part of its defense mechanism, thus restricting the multiplication of viruses in the bacterial cell. Different species of bacteria produce different restriction endonucleases.
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Question 57 of 74
57. Question
In transgenics, expression of transgene in target tissue is determined by (NEET 2004)
CorrectIncorrectHint
(d): The plants, in which a functional foreign gene has been incorporated by any biotechnological methods that generally is not present in plant, are called transgenic plants. When plant cell are transformed by any of the transformation methods it is necessary to isolate the transformed cells/tissue. There are certain selectable marker genes present in vectors that facilitate the selection process. In transformed cells the selectable marker genes or are introduced through vector. There is a number of marker genes which are commonly described as reporter genes screenable genes. Some of the reporter genes which are most commonly used in plant transformation are : cat, gus, lux, nptII., etc.
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Question 58 of 74
58. Question
In recent years, DNA sequences (nucleotide sequence) of \(m t \mathrm{DNA}\) and \(\mathrm{Y}\) chromosomes were considered for the study of human evolution, because
(NEET 2003)CorrectIncorrectHint
(b) : Sequence of both \(m t \mathrm{DNA}\) and \(\mathrm{Y}\) chromosomes are considered for the study of human evolution because they are uniparental in origin. \(m t \mathrm{DNA}\) is inherited along with the maternal cytoplasm and Y chromosome is inherited from father. So they do not take part in recombination. In addition, \(m t \mathrm{DNA}\) has a higher mutation rate then nuclear DNA so that it is more useful for short term evolutionary studies.
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Question 59 of 74
59. Question
Which one of the following bacteria has found extensive use in genetic engineering work in plants? (NEET 2003)
CorrectIncorrectHint
(d):
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Question 60 of 74
60. Question
Manipulation of DNA in genetic engineering became possible due to the discovery of (NEET 2002)
CorrectIncorrectHint
(a) : DNA restriction endonuclease are important class of restriction exonucleases, class II, which cut double-stranded DNA molecules only at sites characterized by a specific nucleotide sequence. Restriction enzymes are isolated from bacterial cells, and are tools for molecular biologists. Several hundred restriction enzymes are now known, each with a specific sequence requirement dictating where it will cut DNA. Some, such as Hind III, make staggered cuts leaving ‘sticky ends’, three nucleotides long protruding on one strand from each severed terminus; others make clean cuts in both strands at the same place and thus generate ‘blunt ends’. Digesting DNA with a restriction enzyme therefore creates a characteristic set of fragments, which can be isolated by electrophoresis and subsequently analysed.
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Question 61 of 74
61. Question
A mutant strain of T4 – Bacteriophage, R-II, fails to lyse the E. coli but when two strains R-IIX and R-IIY are mixed then they lyse the E. coli. What may be the possible reason?
(NEET 2001)CorrectIncorrectHint
(d) : A mutant strain of \(\mathrm{T}_4\)-bacteriophage, RII, fails to lyse the E.coli but when two strains R-II (X) and R-IIY are mixed then they lyse the E.coli because both strains have different cistrons.
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Question 62 of 74
62. Question
In Lederberg’s replica plating experiment what shall be used to obtain streptomycin resistant strain
(NEET 2001)CorrectIncorrectHint
(a) : If streptomycin resistant mutant are to be obtained, material should be allowed to grow on medium lacking streptomycin so that both mutant and wild types may grow. These colonies are imprinted on petriplates to form the master pattern and other plates having streptomycin can then be pressed on velveteen to get an impression. The plate now containing only mutants for streptomycin resistance will grow.
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Question 63 of 74
63. Question
Which of the following cut the DNA from specific places? (NEET 2001)
CorrectIncorrectHint
(a)
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Question 64 of 74
64. Question
Maximum number of bases in plasmids discovered so far (NEET 2001)
CorrectIncorrectHint
(b) : A plasmid is a DNA molecule separate from the chromosomal DNA and capable of autonomous replication. In many cases, it is typically circular and double-stranded. It usually occurs in bacteria, and is sometimes found in eukaryotic organisms. The size of plasmids varies from 1 to over 400 kilobase pairs (kbp). There may be one copy, for large plasmids, to hundreds of copies of the same plasmid in a single cell. The term plasmid was first introduced by the American molecular biologist Joshua Lederberg in 1952.
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Question 65 of 74
65. Question
The bacteria generally used for genetic engineering is (AIPMT 2000)
CorrectIncorrectHint
(a)
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Question 66 of 74
66. Question
Plasmid has been used as vector because (AIPMT 2000)
CorrectIncorrectHint
(a):
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Question 67 of 74
67. Question
The process of replication in plasmid DNA, other than initiation, is controlled by (AIPMT 1999)
CorrectIncorrectHint
(c) : The DNA plasmid replicates in a semiconservative manner. The initiation of replication is controlled by plasmid gene and elongation and termination are controlled by bacterial genes
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Question 68 of 74
68. Question
Which of the following is related to genetic engineering? (AIPMT 1999)
CorrectIncorrectHint
(d)
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Question 69 of 74
69. Question
Recombinant DNA is achieved by cleaving the pro-DNAs by (AIPMT 1998)
CorrectIncorrectHint
(b) : Recombinant DNA is the product obtained after isolating a specific DNA segment and then inserting it into another DNA molecule at a desired position. Restriction endonucleases are the enzymes that digest DNA at specific sites to isolate a specific DNA segment. Thus they are required for producing recombinant DNA.
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Question 70 of 74
70. Question
Two bacteria found to be very useful in genetic engineering experiments are (AIPMT 1998)
CorrectIncorrectHint
(d):
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Question 71 of 74
71. Question
Restriction endonucleases are (AIPMT 1998)
CorrectIncorrectHint
(b) :
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Question 72 of 74
72. Question
Genetic engineering is possible, because (AIPMT 1998)
CorrectIncorrectHint
(b) :
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Question 73 of 74
73. Question
The restriction enzymes are used in genetic engineering, because (AIPMT 1995)
CorrectIncorrectHint
(a):
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Question 74 of 74
74. Question
Which of the following organelles is related with genetic engineering? (AIPMT 1994)
CorrectIncorrectHint
(b) : Plasmids are extrachromosomal genetic element found in many bacteria and in a few eukaryotic cells. Plasmids are closed circles of double-stranded DNA. ranging in size from one to 200 kilobases. They frequently carry genes conferring antibiotic resistance. Plasmids are becoming important tools for genetic engineering since they have the ability to replicate and migrate to daughter cells. Plasmids are widely used as carriers of cloned genes, as for example the E. coli plasmid pBR322. When plasmids are used as cloning vectors and carry a novel DNA sequence they are referred to as chimeric plasmids.