Concepts of Genetics (12th Edition)
12th Edition
ISBN: 9780134604718
Author: William S. Klug, Michael R. Cummings, Charlotte A. Spencer, Michael A. Palladino, Darrell Killian
Publisher: PEARSON
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Chapter 6, Problem 16PDQ
A phage-infected bacterial culture was subjected to a series of dilutions, and a plaque assay was performed in each case, with the results shown in the following table. What conclusion can be drawn in the case of each dilution, assuming that 0.1 mL was used in each plaque assay?
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Chapter 6 Solutions
Concepts of Genetics (12th Edition)
Ch. 6 - When the interrupted mating technique was used...Ch. 6 - In a transformation experiment involving a...Ch. 6 - In complementation studies of the rII locus of...Ch. 6 - A 4-month-old infant had been running a moderate...Ch. 6 - Prob. 2CSCh. 6 - Prob. 3CSCh. 6 - Prob. 4CSCh. 6 - HOW DO WE KNOW? In this chapter, we have focused...Ch. 6 - Review the Chapter Concepts list on p. 123. Many...Ch. 6 - With respect to F+ and F bacterial matings, answer...
Ch. 6 - List all major differences between (a) the F+ F...Ch. 6 - Describe the basis for chromosome mapping in the...Ch. 6 - In general, when recombination experiments are...Ch. 6 - Why are the recombinants produced from an Hfr F...Ch. 6 - Describe the origin of F bacteria and merozygotes.Ch. 6 - In a transformation experiment, donor DNA was...Ch. 6 - Describe the role of heteroduplex formation during...Ch. 6 - Explain the observations that led Zinder and...Ch. 6 - Prob. 12PDQCh. 6 - Two theoretical genetic strains of a virus (abc...Ch. 6 - The bacteriophage genome consists of many genes...Ch. 6 - If a single bacteriophage infects one E. coli cell...Ch. 6 - A phage-infected bacterial culture was subjected...Ch. 6 - In recombination studies of the rII locus in phage...Ch. 6 - In an analysis of rII mutants, complementation...Ch. 6 - If further testing of the mutations in Problem 18...Ch. 6 - Using mutants 2 and 3 from Problem 19, following...Ch. 6 - During the analysis of seven rII mutations in...Ch. 6 - In studies of recombination between mutants 1 and...Ch. 6 - Prob. 23ESPCh. 6 - An Hfr strain is used to map three genes in an...Ch. 6 - A plaque assay is performed beginning with 1 mL of...Ch. 6 - In a cotransformation experiment, using various...Ch. 6 - For the experiment in Problem 26, another gene, g,...Ch. 6 - Bacterial conjugation, mediated mainly by...Ch. 6 - A study was conducted in an attempt to determine...
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- A plaque assay is performed beginning with 1 mL of a solution containing bacteriophages. This solution is serially diluted 3 times by combining 0.1 mL of each sequential dilution with 9.9 mL of liquid medium. Then 0.1 mL of the final dilution is plated in the plaque assay and yields 12 plaques.What is the initial density of bacteriophages in the original 1 mL? Enter your answer to two significant figures ( for example: 1.1 * 10^2)arrow_forwardA phagehunter performs a spot titer using standard techniques (3 ul of each dilution spotted to lawn) of a lysate obtained from an optimum webbed plate experiment. The phagehunter counts 8 plaques on the 10-7 dilution spot. Which of the following scenarios is the best choice for the phagehunter to do next? a.) The phagehunter has not achieved a high enough titer lysate to move forward with characterization experiments, so they should go back to the pick-a-plaque experiment. b.) The phagehunter has not achieved a high enough titer lysate to move forward with characterization experiments, so they should adopt a phage from direct isolation. c.) The phagehunter has not achieved a high enough titer lysate to move forward with characterization experiments, so they should try to make more optimum webbed plates. d.) The phagehunter has achieved a high enough titer lysate to move forward with characterization experiments.arrow_forwardConsidering counting rules, calculate the initial titre of the sample viral stock if the following plaques were counted in a plaque assay. Show clear sample calculations. Table 1: Plaque assay counts for lambda phage stock titre enumeration of average concentration (PFU/mL) Total dilution of viral stock 1/13500000 1/135000000 1/135000000 plated Volume diluted viral stock 0.1 0.1 0.1 plated (mL) PFU replicate 1 TNTC 275 25 Calculated concentration (PFU/mL) replicate 1 PFU replicate 2 TNTC 239 23 Calculated concentration (PFU/mL) replicate 2 Average concentration (PFU/mL)arrow_forward
- In the Avery, McLeod, McCarty Experiment where supernatant from heat killed, virulent S Strain pneumonia solutions were added to non-virulent R Strain pneumonia cell cultures and allowed to grow in liquid media (i.e., broth). In tubes where Protease was added to the supernatant prior to cell culture, what was the observed effect when plating and growing the S. pneumonia cells to solid media? Selected answer will be automatically saved. For keyboard navigation, press up/down arrow keys to select an answer. a b C d e All RNA was degraded and Transformation of the R Strain to S Strain occurred. All Protein was degraded and Transformation of the R Strain to S Strain occurred. All DNA was degraded and Transformation of the R Strain to S Strain occurred. All RNA was degraded and no Transformation occurred indicating RNA is the molecule of Transformation inheritance None of the above are truearrow_forwardA phage-infected bacterial culture was subjected to a series ofdilutions, and a plaque assay was performed in each case, withthe following results. What conclusion can be drawn in the caseof each dilution? Dilution Factor Assay Results(a) 104 All bacteria lysed(b) 106 14 plaques(c) 108 0 plaquesarrow_forwardIn the Avery, McLeod, McCarty Experiment where supernatant from heat killed, virulent S Strain pneumonia solutions were added to non-virulent R Strain pneumonia cell cultures and allowed to grow in liquid media (i.e., broth). In tubes where Protease was added to the supernatant prior to cell culture, what was the observed effect when plating and growing the S. pneumonia cells to solid media?arrow_forward
- You have conducted serial 10-fold dilutions and measured the cfu (colony forming units) of a Streptococcus pneumoniae culture and also the pfu (plaque forming units) of a phage (virus) that infects the bacteria. You counted 5 cfu in a 0.4 ml sample of a 106 dilution of the bacterial sample. You then counted 50 plaque-forming units (pfu) in a 0.25 ml sample of a 108 diluted sample of the phage culture. What are the cfu/ml of the S. pneumoniae and pfu/ml of the phage cultures before dilution? 5 x 106 cfu/ml and 2 x 109 pfu/ml 4 x 107 CFU/ml and 2 x 109 PFU/ml 1.25 x 108 cfu/ml and 10 x 1010 pfu/ml 1.25 x 107 cfu/ml and 2 x 1010 pfu/mlarrow_forwardWhat is the purpose of conducting a modified Furter-Meyer Test? What is the principle behind this test? How could you identify the positive result for this test?arrow_forwardDuring the incubation step of the plaque assay, viral replication leads to host cell lysis. This allows the freshly-released virions to diffuse through the media and infect new hosts. The amount of agar added to the top agar is 7 g per liter rather than the 16 g of agar per liter for most solid media, including the bottom agar used in this assay. How would it change the plaque assay results if bottom agar was used in place of the top agar in this assay? a- The diameter of the plaques would be smaller. b- The diameter of the plaques would not change. c- The diameter of the plaques would be larger. (2) A researcher measured the viral titer of PhiX174 in fish tank water, untreated sewage water, and unpasteurized apple juice. Which sample do you predict will have the highest titer on this page? a- Fish tank water b- Unpasteurized apple juice c- Untreated sewage waterarrow_forward
- Draw a dilution scheme for a dilution of phage from 1.5 x 1010 PFU/mL to 1.00 x 102 PFU/mL. Achieve this serial dilution considering the following: The volumes of each dilution should be 1.0mL. It is not advisable to perform any dilutions > 1/100. The first dilution in any titre determination of stock phage should use 10µl or less of stock.arrow_forwardIn the ELISA, the pH the coating buffer was 9.6 whereas the pH of the sample buffer (PBS based) was 7.4 a) Why was the pH of the coating buffer so different?b) What is “coating buffer” for an ELISA? Does the buffer molecule usedmake sense based on the desired pH?In an ELISA procedure the samples are incubated and the ELISA plate iscovered with parafilm and placed in a humidified chamber to preventevaporation of the small liquid volumes in the wells.c) How would your results change if you did not incubate in a humidifiedchamber?arrow_forwardTo determine the number of cells in a pure culture of Klebsiella pneumoniae, you have performed a serial dilution using three tubes of sterile saline (9.9 ml each). A sample of 0.1 ml from the culture was added to tube 1. Similarly, 0.1 ml from tube 1 was used to inoculate tube 2, and tube 3 was inoculated using 0.1 ml from tube 2. A nutrient agar plate was then inoculated using 0.1 ml from tube 3 and incubated overnight. The next day, 92 colonies were observed on the plate. How many cfu/ml were in the original culture? Using a Petroff-Hauser counting chamber, the number of cells in the same culture was estimated to be 8.5 • 109 cells/ml. How can you explain these results?arrow_forward
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