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New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.
Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.
Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.
To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.
The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.
Q.
It can be inferred from the passage that the replica plating method is effective for which of the following reasons?
  • a)
    It allows researchers to determine the relative sizes of different populations of bacteria.
  • b)
    It shows that no new mutant strains developed after transfer from the original agar plate.
  • c)
    It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.
  • d)
    It demonstrates that no tryptophan was present in the original agar culture.
  • e)
    It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.
Correct answer is option 'B'. Can you explain this answer?
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New research by Paul Fildes and K. Whitaker challenges the theory that...
The replica plating method is discussed in the third paragraph. The first two sentences describe the process, while the third sentence explains what was learned by using this method. The correct inference about the effectiveness of the replica plating method will be a virtual rephrasing of the facts presented in the third paragraph.  
(A) We cannot infer that the replica plating method allows researchers to determine the relative sizes of different populations of bacteria. The population sizes of various bacteria populations were never discussed.
(B) CORRECT. The last sentence of the passage states that “the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate,” citing this as proof that “the mutants were in fact genetically present or preadapted.” In other words, the mutant strains did not develop after transfer from the original agar plate.
(C) The only type of bacteria mentioned in the passage was bacteria typhosum, so we cannot infer that the replica plating method eliminates the possibility that the agar culture was contaminated by a different type of bacteria.
(D) The role of tryptophan is discussed in the first and second paragraphs. This answer choice goes too far by asserting that “no tryptophan was present in the original agar culture.” We do not have enough information to make that inference.
(E) According to the first paragraph, “the necessary metabolites for bacterial reproduction” are defined as the substances “necessary for their (bacteria’s) regular function.” In the case of bacteria typhosum, that substance is tryptophan. We do not have enough information to infer that the replica plating method establishes that the original agar culture contained tryptophan. If fact, the presence of mutant strains of bacteria on the replica plates would contradict this statement rather than support it.  
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New research by Paul Fildes and K. Whitaker challenges the theory that...
Understanding the Replica Plating Method
The effectiveness of the replica plating method used by Fildes and Whitaker can be inferred from its ability to demonstrate that no new mutant strains developed after the transfer from the original agar plate. Here’s how:
Key Reasons for Effectiveness
- Transfer of Growth Patterns: The replica plating technique allowed researchers to imprint the growth patterns from the original agar plate onto new plates. This direct transfer means that if the mutants were not present in the original sample, they would not appear in the replicas.
- Identical Locations: The mutants found on the replica plates were located in the same positions as on the original plate. This consistency indicates that the mutants were already part of the original culture and were not formed due to environmental conditions or the transfer process.
- Genetic Origin Confirmation: By demonstrating that the mutants were present in both the original and replica plates, Fildes and Whitaker confirmed that these mutant strains existed genetically prior to the experiment, negating the theory of environmental training.
Implications of the Findings
- No New Mutants: The results imply that the experimental conditions did not induce new mutations. Instead, the mutants were pre-existing, showing that the concentration of tryptophan or growth conditions did not lead to the emergence of new strains.
- Challenges Previous Theories: This evidence undermines the previous assumption about training bacteria to mutate by environmental stressors, reinforcing the genetic basis of the mutants' appearance.
In conclusion, option 'B' accurately reflects the core finding that no new mutant strains developed as a result of the transfer, underscoring the genetic stability of the bacterial populations.
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New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.According to the passage, Fildes and Whitaker conducted the experiment with liquid culture because

New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.Which of the following most accurately states the purpose of the passage?

The accumulation of scientific knowledge regarding the environmental impact of oil well drilling in North America has tended to lag behind the actual drilling of oil wells. Most attempts to regulate the industry have relied on hindsight: the need for regulation becomes apparent only after undesirable events occur. The problems associated with oil wells’ potential contamination of groundwater—fresh water within the earth that supplies wells and springs—provide a case in point.When commercial drilling for oil began in North America in the mid-nineteenth century, regulations reflected the industry’s concern for the purity of the wells’ oil. In 1893, for example, regulations were enacted specifying well construction requirements to protect oil and gas reserves from contamination by fresh water. Thousands of wells were drilled in such a way as to protect the oil, but no thought was given to the possibility that the groundwater itself might need protection until many drinking-water wells near the oil well sites began to produce unpotable, oil contaminated water.The reason for this contamination was that groundwater is usually found in porous and permeable geologic formations near the earth’s surface, whereas petroleum and unpotable saline water reservoirs are generally found in similar formations but at greater depths. Drilling a well creates a conduit connecting all the formations that it has penetrated. Consequently, without appropriate safeguards, wells that penetrate both groundwater and oil or saline water formations inevitably contaminate the groundwater. Initial attempts to prevent this contamination consisted of sealing off the groundwater formations with some form of protective barrier to prevent the oil flowing up the well from entering or mixing with the natural groundwater reservoir. This method, which is still in use today, initially involved using hollow trees to seal off the groundwater formations; now, however, large metal pipe casings, set in place with cement, are used.Regulations currently govern the kinds of casing and cement that can be used in these practices; however, the hazards of insufficient knowledge persist. For example, the long-term stability of this way of protecting groundwater is unknown. The protective barrier may fail due to corrosion of the casing by certain fluids flowing up the well, or because of dissolution of the cement by these fluids. The effects of groundwater bacteria, traffic vibrations, and changing groundwater chemistry are likewise unassessed. Further, there is no guarantee that wells drilled in compliance with existing regulations will not expose a need for research in additional areas: on the west coast of North America, a major disaster recently occurred because a well’s location was based on a poor understanding of the area’s subsurface geology. Because the well was drilled in a channel accessing the ocean, not only was the area’s groundwater completely contaminated, but widespread coastal contamination also occurred, prompting international concern over oil exploration and initiating further attempts to refine regulations.Which one of the following most accurately states the main point of the passage?

A basic principle of ecology is that population size is partly a reflection of available food resources. Recent experiments suggest that the relationship is more complex than formerly thought. Specifically, the browsing of certain rodents appears to trigger chemical reactions in food plants which, in turn, affect the size of the rodent populations. Two examples of such regulation have been reported.Berger has demonstrated the power of a naturally occurring chemical called 6-MBOA to stimulate reproductive behavior in the mountain vole, a small mouse-like rodent. 6 MBOA forms in young grass in response to browsing by voles. Berger experimented by feeding oats coated with 6-MBOA to non-breeding winter populations of voles. After three weeks, she found a high incidence of pregnancy among females. Since the timing of reproduction is crucial to the short-lived vole in an environment in which the onset of vegetative growth may be considerably delayed, the phytochemical triggering of reproductive behavior represents a significant biological adaptation.In an example reported by Bryant, plants appear to have developed a phytochemical defense against the depredations of snowshoe hares in Canada. Every ten years, for reasons that are unclear, the hare population swells. The result is overbrowsing of certain deciduous trees and shrubs. Bryant found that trees favored by the hare produce young shoots high in terpene and phenolic resins, which discourage hare browsing. After treating non-resinous willow twigs with resinous extracts and placing treated and untreated samples at hare feeding stations, Bryant found that samples containing at least half of the resin concentration of natural twigs were untouched. The avoidance of resinous shoots, he concludes, may play a role in the decline of the hare population to normal levels.Both of these reports suggest areas for further research. For example, data should be reviewed to determine if periodic population explosions among lemmings (another small rodent living in a northern environment) occur during years in which there is an early onset of vegetative growth; if so, a triggering mechanism similar to that prompted by the vole may be involved.The author provides specific information to answer which of the following questions?

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New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer?
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New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? for GMAT 2024 is part of GMAT preparation. The Question and answers have been prepared according to the GMAT exam syllabus. Information about New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for GMAT 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer?.
Solutions for New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for GMAT. Download more important topics, notes, lectures and mock test series for GMAT Exam by signing up for free.
Here you can find the meaning of New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer?, a detailed solution for New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? has been provided alongside types of New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice New research by Paul Fildes and K. Whitaker challenges the theory that strains of bacteria can be “trained” to mutate by withholding a metabolite necessary for their regular function. In particular, they consider the case of bacteria typhosum, which needs tryptophan in order to reproduce. Earlier researchers had grown the bacteria in a medium somewhat deficient in tryptophan and observed the growth of mutant strains of the bacteria which did not need tryptophan in order to reproduce.Fildes and Whitaker argue that the withholding of tryptophan did not induce these mutant strains of bacteria.Rather, these mutants were already present in the original sample of bacteria typhosum, albeit in a concentration too small to detect. In experimenting with the bacteria grown in agar cultures, they found that by plating out huge quantities of the bacteria, one could locate mutant strains. Because of the possibility that the lack of uniformity of the agar cultures had in fact trained mutant strains, they conducted similar experiments with liquid cultures and again found that mutant strains of the bacteria were present in the original sampling. From these experiments, Fildes and Whitaker conclude that the mutants are of genetic origin and are not induced by environmental training. They asserted that the concentration of tryptophan is unrelated to the appearance of these mutants in the bacteria.To confirm these results, Fildes and Whitaker used an innovative plating technique using pile fabrics, such as velvet or velveteen, to accurately imprint the growth found on an original agar plate to a series of replica agar plates.The process entails taking the original agar plate, inverting it onto the velvet while using light finger pressure to transfer growth, and then imprinting the fabric, with its pattern of growth, on the new agar plates. By using this replica plating method, Fildes and Whitaker demonstrated that the mutants were in fact genetically present or preadapted, as the locations of the mutant strains of bacteria on the replica plates were identical to the locations of the mutant strains on the original agar plate.Q.It can be inferred from the passage that the replica plating method is effective for which of the following reasons?a)It allows researchers to determine the relative sizes of different populations of bacteria.b)It shows that no new mutant strains developed after transfer from the original agar plate.c)It eliminates the possibility that the agar culture was contaminated by a different type of bacteria.d)It demonstrates that no tryptophan was present in the original agar culture.e)It establishes that the original agar culture contained the necessary metabolites for bacterial reproduction.Correct answer is option 'B'. Can you explain this answer? tests, examples and also practice GMAT tests.
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