Concept explainers
When Griffith injected mice with a combination of live rough-strain and heat-killed smooth-strain pneumococci, he discovered that (a) the mice were unharmed (b) the dead mice contained living rough-strain bacteria (c) the dead mice contained living smooth-strain bacteria (d) DNA had been transferred from the smooth-strain bacteria to the mice (e) DNA had been transferred from the rough-strain bacteria to the smooth-strain bacteria
Introduction: Transformation is a process by which bacterial cells uptake naked DNA from its environment. It is a process of horizontal gene transfer by which the genome of the bacteria gets altered due to the uptake of foreign gene. The experimental demonstration of transformation was done by bacteriologist Frederick Griffith.
Answer to Problem 1TYU
Correct answer: When Griffith injected mice with a combination of live rough-strain and heat-killed smooth-strain of pneumococci, he discovered that the dead mice contained living smooth-strain bacteria.
Hence, the correct answer is option (c).
Explanation of Solution
Reason for the correct answer:
Frederick Griffith’s principle of transformation states that a harmless strain of bacteria can be made virulent by exposing it to heat-killed bacterial strains. Griffith started the experiment to find out a vaccine against pneumonia. He selected two strains of pneumococci:
- 1. Smooth (S) strain that has a polysaccharide coat which makes them virulent strain.
- 2. Rough (R) strain that lacks capsule which makes them non-virulent strain.
The mice died when they were injected with the virulent S form of pneumococci. Pneumonia was not caused when the non-virulent R strain injection was given to the mice. Again mice survived when they were injected with the heat-killed S form. Then a mixture of heat-killed S and R strain was injected to the mice. The mice died by causing pneumonia. By all these observations, it concluded that virulent genes from the heat-killed S strain that causes pneumonia in mice got transformed to the non-virulent living R strain. Hence, he concluded that the transformation of the virulent gene made the harmless bacteria dangerous.
Option (c) is given as “the dead mice contained living smooth-strain bacteria”.
The mice died and live smooth cells were found in the dead mice.
Hence, the correct answer is option (c).
Reasons for incorrect answers:
Option (a) is given as, “the mice were unharmed”.
In the Griffith experiment, the mice died when injected with a combination of live rough cells and heat-killed smooth cells.
Hence, option (a) is incorrect.
Option (b) is given as, “the dead mice contained living rough-strain bacteria”.
The dead mice contained living smooth cells but not living rough cells.
Hence, option (b) is incorrect.
Option (d) is given as, “DNA had been transferred from the smooth-strain bacteria to the mice”.
The DNA from bacteria does not usually transfer to the host in which it lives. The DNA of mice was unaffected due to the presence of bacteria.
Hence, option (d) is incorrect.
Option (e) is given as, “DNA had been transferred from the rough-strain bacteria to the smooth-strain bacteria”.
The DNA was transferred from the smooth-strain bacteria to rough-strain bacteria.
Hence, option (e) is incorrect.
Hence, the options (a), (b), (d), and (e) are incorrect.
The DNA was transferred from the smooth-strain bacteria to rough-strain bacteria. Thus, the mice die and live smooth cells were found in the dead mice.
Want to see more full solutions like this?
Chapter 12 Solutions
Biology (MindTap Course List)
- In his work with pneumonia-causing bacteria andmice, Griffith found that(A) the protein coat from pathogenic cells wasable to transform nonpathogenic cells.(B) heat-killed pathogenic cells causedpneumonia.(C) some substance from pathogenic cells was transferred tononpathogenic cells, making them pathogenic.(D) the polysaccharide coat of bacteria causedpneumonia.arrow_forward-Two hundred patients without chest pain were screened with a new biochemical test that showed 190 had a negative screening result. What is the test's specificity? a) 80% b) 95% c) 90% d) 75%arrow_forward65. Destruction of the group of cells identified by the arrows in the photomicrograph shown is most likely to result in which of the following conditions? A) Anemia B) Cirrhosis C) Impotence D) Type 1 diabetes mellitus E) Ulcerarrow_forward
- QUESTION 2 In the Luria Delbruck experiment, what did the appearance of a bacterial colony on a petri plate indicate? O A) The bacterial colony was derived from one initial cell that was resistant to infection by the bacteriophage. O B) The bacterial colony was made up of many cells that became resistant to bacteriophage infection independently. O C)A colony formed when a bacterial cell was not resistant to bacteriophage infection. O D) The bacterial cells that made up a colony were resistant to antibiotic. O E. phage caused mutations to occur in some of the plates but not in others.arrow_forwardIn a process of production of a recombinant protein by E. coli cells, it was observed accumulation of acetate in the culture medium. In this situation, it can be said that: (a) certainly the process in question was being conducted in anaerobiosis (B).Acetate accumulation is advantageous for the process as the acetate formation reaction generates 1 molecule of ATP (c)Knowing that decreasing the temperature of the process causes a reduction in the rate of glycolysis, this could be a strategy to reduce the accumulation of acetate (d).the acetate formed can be re-assimilated by the cell if the glyoxylate pathway is activated at some point in the culturearrow_forwardIn the document you submit, please shortly describe the results for this test… (like yellow equals what?)1) Give me the expected results: a) Phenol Red Glucose: Staphylococcus aureus, Alcaligenes faecalis, and Escherichia coli b) Phenol Red Lactose: Alcaligenes faecalis, and Escherichia coli c) Phenol Red Sucrose: Staphyloccocus aureus and Enterococcus faecalisarrow_forward
- (a) Discuss the role of chromosomal islands in microbial diversity. (b) State three reasons why chromosomal islands are presumed to be of "foreign" origin.arrow_forwardRegarding the cultivation of animal cells in vitro, it is correct to state that: *(Only one statement is correct) a) Transformed cells differ from normal and established cells in that they have the ability to proliferate indefinitely in culture b) Transformed cells derive from isolated and dissected tumors, constituting cell lines that have limited cultivation time c) The genetic instability presented in normal cells makes them preferential models for the production of recombinant proteins d) Cells cultured in adhesion must be periodically expanded, through the use of enzymes such as trypsin e) The metabolism of carbon sources in the culture medium by animal cells generates products such as lactate, which positively influence their productivityarrow_forward1) The inactivation of Staphylococcus aureus was studied in pomegranate juice heated at 75°- 95°C. The slopes for the inactivation of this bacteria were calculated from the linear lines in semi-log graphical paper. The slope values were presented in Table 1. a) Determine the temperature change needed to inactivate this bacteria by 90%. b) Temperature change to inactivate Bacillus cereus in pomegranate juice by 90% at the same temperature range was 29°F. At 75°-95°C temperature range, which bacteria will be more affected by the temperature changes? Commend on your answer in one sentence Table 1- Slope values for the inactivation of Staphylococcus aureus in pomegranate juice heated at various temperature Temp. (°C) 75 80 85 95 -Slope x 10² (min-¹) 2.222 3.704 5.000 13.158arrow_forward
- Regarding recombinant vaccines, it is INCORRECT to state that: (Only one statement corresponds to the answer) * (a) They are free from infectious viral particles, which increases safety in production and use (b) The development of recombinant vaccines is generally faster than conventional vaccines from inactivated or attenuated pathogens (c) Expansion of production scale is easier than conventional vaccines, since they are produced using fermentation methods in bioreactors (d) The development of recombinant vaccines depends on industrial cultivation methods of the pathogen of interest (e) Recombinant vaccines can be produced on different platforms, such as animal and microorganism cellsarrow_forwardRegarding the production of recombinant monoclonal antibodies, it is CORRECT to state that: * (JUST ONE STATEMENT IS CORRECT) (A) Chimeric and humanized antibodies differ in relation to the percentage of sequence of the constant chain of molecules from the human genome (B) Chimeric antibodies are industrially produced by joining purified protein fragments of the Fab fraction of murine antibodies and the constant portion of human antibodies. (C) When using cells dependent on the DHF amplification system, we must use a vector containing the coding information of the light and heavy chains and another vector that contains the coding sequence of the enzyme dihydrofolate reductase (D)The industrial purification of monoclonal antibodies should preferably use an initial step based on the use of affinity columns, which will bind the antibodies by the Fc fraction (E) The use of amplification systems such as GS and DHFR has as main objective to make the production of monoclonal antibodies…arrow_forwardDescribe the experiment done by Frederick Griffith in 1928, where the non-lethal (rough) strain of Streptococcus pneumoniae bacteria killed experimental mice when mixed with the heat-killed smooth strain. Discuss what may have happened to the rough strain after the heat-killed smooth strain was introduced and why you think the rough strain killed the mice. What would be the conclusion and significance of this study and its finding?arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education