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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Textbook Question
Chapter 6, Problem 13PDQ
Two theoretical genetic strains of a virus (a−b−c− and a+b+c+) were used to simultaneously infect a culture of host bacteria. Of 10,000 plaques scored, the following genotypes were observed. Determine the genetic map of these three genes on the viral chromosome. Decide whether interference was positive or negative.
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10 mL of a bacteriophage suspension is mixed with 5 mL of a bacterial culture and 25% of the phages adsorb. The bacteriophage suspension has a concentration of 4x1018 viruses per mL, and the bacterial culture had a concentration of 6x1014 bacteria per mL.
How many viruses are adsorbed per cell (multiplicity of infection)?
What fraction of the cells is uninfected?
What fraction of the cells is single infected?
What fraction of the cells is multiple infected?
Two 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?
Considering 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)
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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