Genetics: Analysis and Principles
6th Edition
ISBN: 9781259616020
Author: Robert J. Brooker Professor Dr.
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Question
Chapter 7, Problem 11EQ
Summary Introduction
To review:
An experimental strategy to get a
Introduction:
Bacterial cells transmit their genome by various mechanisms (conjugation, transduction, and transformation). Transduction is the method by which the foreign genetic mattergets introduced in bacterial cells by usinga virus.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
E. coli cells are simultaneously infected with two strains of phage λ. One strain has a mutant host range, is temperature sensitive, and produces clear plaques (genotype h st c); another strain carries the wildtype alleles (genotype h+ st+ c+). Progeny phages are collected from the lysed cells and are plated on bacteria. The following numbers of different progeny phages are obtained: Progeny phage genotype Number of plaques h+ c+ st+ 321 h c st 338 h+ c st 26 h c+ st+ 30 h+ c st+ 106 h c+ st 110 h+ c+ st 5 h c st+ 6 a. Determine the order of the three genes on the phage chromosome. b. Determine the map distances between the genes. c. Determine the coefficient of coincidence and the interference
Bacterial conjugation has medical consequences. For example, certain plasmids contain genes that code for toxins. The causative agent of a deadly form of food poisoning, E. coli 0157, synthesizes a toxin that causes massive bloody diarrhea and kidney failure. This toxin is now believed to have originated in Shigella, another bacterium that causes dysentery. Similarly, the growing problem of antibiotic resistance is partly attributable to the spread of antibioticresistant genes among bacterial populations. Antibiotic resistance develops because antibiotics are overused in medical practice and in livestock feeds. Suggest a mechanism by which this extensive use promotes antibiotic resistance.
This question combines your knowledge of bacterial conjugationand the genetic regulation that directs thephage λ reproductive cycles. When researchers mix donor Hfr strains with recipient F– bacteria that are lysogenic for phage λ, the conjugated cells survive normally. However, if donor Hfr strains that are lysogenic for phage λ conjugate with recipient F– bacteria that do not contain any phage λ, the recipient cells often lyse, due to the induction of λ into the lytic cycle. Based on your knowledge of the regulation of the two reproductive cycles of phage λ, explain this experimental observation.
Chapter 7 Solutions
Genetics: Analysis and Principles
Ch. 7.1 - 1. A form of genetic transfer that involves the...Ch. 7.2 - 1. A bacterial cell with an F factor conjugates...Ch. 7.2 - 2. Which of the following is a type of plasmid?...Ch. 7.3 - 1. With regard to conjugation, a key difference...Ch. 7.3 - 2. In mapping experiments, ______ strains are...Ch. 7.4 - Prob. 1COMQCh. 7.4 - Cotransduction may be used to map bacterial genes...Ch. 7.5 - Prob. 1COMQCh. 7.5 - Prob. 2COMQCh. 7.6 - 1. Which of the following is an example of...
Ch. 7 - 1. The terms conjugation, transduction, and...Ch. 7 - Prob. 2CONQCh. 7 - If you mix together an equal number of F+ and F...Ch. 7 - What is the difference between an F+ and an Hfr...Ch. 7 - 5. What is the role of the origin of transfer...Ch. 7 - 6. What is the role of sex pili during...Ch. 7 - Prob. 7CONQCh. 7 - Prob. 8CONQCh. 7 - Prob. 9CONQCh. 7 - 10. What is cotransduction? What determines the...Ch. 7 - Prob. 11CONQCh. 7 - Prob. 12CONQCh. 7 - Describe the steps that occur during bacterial...Ch. 7 - Prob. 14CONQCh. 7 - Prob. 15CONQCh. 7 - Antibiotics such as tetracycline, streptomycin,...Ch. 7 - Prob. 1EQCh. 7 - 2. In the experiment of Figure 7.1, Lederberg and...Ch. 7 - Explain how a U-tube apparatus can distinguish...Ch. 7 - Prob. 4EQCh. 7 - 5. In a conjugation experiment, what is meant by...Ch. 7 - In your laboratory, you have an F strain of E....Ch. 7 - 7. As mentioned in question 2 of More Genetic...Ch. 7 - An Hfr strain that is hisE+ and pheA+ was mixed...Ch. 7 - Acridine orange is a chemical that inhibits the...Ch. 7 - Prob. 10EQCh. 7 - Prob. 11EQCh. 7 - Lets suppose a new strain of P1 phage has been...Ch. 7 - If two bacterial genes are 0.6 minute apart on the...Ch. 7 - 14. In a cotransduction experiment involving P1,...Ch. 7 - Prob. 15EQCh. 7 - Prob. 16EQCh. 7 - 1. Discuss the advantages of the genetic analysis...Ch. 7 - Prob. 2QSDC
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- The figure above shows a schematic of genes and transcription control elements from phage λ. Use this figure as an aid to help you describe the molecular events involved in: a) The establishment of lysogeny b) The establishment of a lytic life cyclearrow_forwardThe size of a DNA fragment that can be inserted into an unmodified λ vector is very limited. Large segment in the central region of the λ DNA molecule can be removed without affecting the ability of the phage to infect Escherichia coli cells. However, the deletion of this non- essential region does affect the life cycle of the bacteriophage. Explain this statement.arrow_forwardIn Hershey-Chase experiment, bacteriophages protein coats were tagged with radioactive isotope S-32. These phages were used to infect E. coli cells and the cells were further centrifuged to form pellets. Why was the radioactivity level of S-32 found greater outside the cells compared to the E. coli cell pellets? Explain briefly. If the experiment is repeated in the same manner but this time the phage protein coats are labelled with isotope X and the phage DNA with isotope Y, which isotope’s radioactivity will be found in greater amounts in the E. coli cell pellets after centrifugation? Explain briefly.arrow_forward
- Consider three genes in E. coli: thr+, ara+, and leu+ (which give the cell the ability to synthesize threonine, arabinose, and leucine, respectively). All three of these genes are close together on the E. coli chromosome. Phages are grown in a thr+ ara+ leu+ strain of bacteria (the donor strain). The phage lysate is collected and used to infect a strain of bacteria that is thr− ara− leu −. The recipient bacteria are then tested on selective medium lacking leucine. Bacteria that grow and form colonies on this medium (leu+ transductants) are then replica-plated on medium lacking threonine and on medium lacking arabinose to see which are thr+ and which are ara+. Another group of the recipient bacteria are tested on medium lackingthreonine. Bacteria that grow and form colonies on this medium (thr+ transductants) are then replica-plated on medium lacking leucine and onto medium lacking arabinose to see which are ara+ and which are leu+. Results from these experiments are as follows:…arrow_forwardConsider a hypothetical phage whose DNA replicates exclusively by rolling circle replication. A phage with radioactive DNA in both strands infects a bacterium and is allowed to replicate in a nonradioactive medium. Assume that only daughter DNA from the elongated branch ever gets packaged into progeny particles. What fraction of the parental radioactivity will appear in the progeny phage? How many progeny phage will contain radioactive DNA? What is the fundamental difference between the initiation of θ replication and that of the rolling circle?arrow_forwardOne of the reasons why phage therapy has not been applied widely is that bacteria can become resistant to bacteriophages as well, through mutations in genes encoding for specific proteins. What would be a protein in the bacterial cell that, if mutated, would make that cell resistant to phage infection?arrow_forward
- When various strains of λ phage are seeded on a lawn of E. coli, they can form clear or turbid plaques. (b) For mutant λ phages that can only form clear plaques, give two different types of mutation in the phage that can explain the clear plaque phenotype.arrow_forwardTwo mutations that affect plaque morphology in phages (a and b ) have been isolated. Phages carrying both mutations (a b) are mixed with wild-type phages (a* b*) and added to a culture of bacterial cells. Once the phages have infected and lysed the bacteria, samples of the phage lysate are collected and cultured on plated bacteria. The following numbers of plaques are observed: Plaque phenotype Number a* b* 2043 a* b- 320 a b* 357 2134 What is the frequency of recombination between the a and b genes?arrow_forwardThe bacteriophage genome consists of many genes encoding proteins that make up the head, collar, tail, and tail fibers. When these genes are transcribed following phage infection, how are these proteins synthesized, since the phage genome lacks genes essential to ribosome structure?arrow_forward
- If a single bacteriophage infects one E. coli cell present on a lawn of bacteria and, upon lysis, yields 185 viable viruses, how many phages will exist in a single plaque if 5 more lytic cycles occur? Express your answer using three significant figures (example: 1.11×10^3).arrow_forwardNine rII− mutants of bacteriophage T4 were used inpairwise infections of E. coli K(λ) hosts. Six of themutations in these phages are point mutations; theother three are deletions. The ability of the doubly infected cells to produce progeny phages in large numbers is scored in the following chart.1 2 3 4 5 6 7 8 91 − − + + − − − + +2 − + + − − − + +3 − − + − + − −4 − + − + − −5 − − − + +6 − − − −7 − + +8 − −9 −The same nine mutants were then used in pairwise infections of E. coli B hosts. The production of progenyphages that can subsequently lyse E. coli K(λ) hosts isnow scored. In the table, 0 means the progeny do notproduce any plaques on E. coli K(λ) cells; − meansthat only a very few progeny phages produce plaques;and + means that many progeny produce plaques(more than 10 times as many as in the − cases).1 2 3 4 5 6 7 8 91 − + + + + − − + +2 − + + + + − + +3 0 − + 0 + + −4 − + − + + +5 − + − + +6 0 0 − +7 0 + +8 − +9 −a. Which of the mutants are the three deletions? Whatcriteria did…arrow_forwardwhen various strains of lambda phage are seeded on a lawn of e.coli, they can form clear or turbid plaques. Explain the difference between the two types of plaques. can all bacteriophage form clear and turbid plaques?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Biology: The Dynamic Science (MindTap Course List)BiologyISBN:9781305389892Author:Peter J. Russell, Paul E. Hertz, Beverly McMillanPublisher:Cengage Learning
Biology: The Dynamic Science (MindTap Course List)
Biology
ISBN:9781305389892
Author:Peter J. Russell, Paul E. Hertz, Beverly McMillan
Publisher:Cengage Learning
Molecular Techniques: Basic Concepts; Author: Dr. A's Clinical Lab Videos;https://www.youtube.com/watch?v=7HFHZy8h6z0;License: Standard Youtube License