Chapter 6 Genetic Analysis and Mapping in Bacteria and Bacteriophages1) Name two forms of recombination in bacteria.A) lytic and lysogenicB) auxotrophic and prototrophicC) conjugation and transductionD) mixed and generalizedE) insertion and replicationAnswer: CSection: 6.2, 6.5, 6.72) Bacteriophages engage in two interactive cycles with bacteria. What are these cycles?A) lytic and lysogenicB) insertion and replicationC) auxotrophic and prototrophicD) heteroduplex and homoduplexE) negative and positiveAnswer: ASection: 6.63) A bacteriophage that is capable of entering either a lytic or lysogenic cycle is called a(n) ________.A) temperate bacteriophageB) virulent bacteriophageC) plasmidD) episomeE) plaque-forming unitAnswer: ASection: 6.64) Transduction is a form of recombination in bacteria that involves ________.A) 5-bromouracilB) F plasmidsC) bacteriophagesD) fertility factorsE) physical contact between the bacteria involvedAnswer: CSection: 6.71Copyright © 2012 Pearson Education, Inc.5) The clearing made by bacteriophages in a "lawn" of bacteria on an agar plate is called a ________.A) clear zoneB) lysogenic zoneC) prophageD) plaque.E) host rangeAnswer: DSection: 6.66) Name the general category into which double-stranded circular extrachromosomal DNA elements such as F factors, ColE1, and R would fall.A) capsidB) r-determinantC) plaqueD) partial diploidE) plasmidAnswer: ESection: 6.47) Temperate phages are those that can enter either the ________ or ________ cycle.A) lytic; lysogenicB) virulent; avirulentC) functional; nonfunctionalD) former; nonformerE) complementing; competingAnswer: ASection: 6.68) Lysogeny is an important phenomenon in bacteria and phages. Briefly describe lysogeny (using labeled diagrams if helpful).Answer: Lysogeny is the process in which a temperate bacteriophage infects a bacterial cell and subsequently integrates its chromosome into the bacterial chromosome.Section: 6.69) Compare and contrast bacteriophage lysis and lysogeny.Answer: Both lysis and lysogeny involve bacterial/phage interactions related to the production of phage progeny. Lysis occurs when progeny phage burst from the bacterial cell; lysogeny involves the incorporation of the phage chromosome into the bacterial chromosome.Section: 6.610) Jacob, Wollman, and others developed a linkage map of E. coli that is based on time. What form of recombination is involved in generating a linkage map based on time?Answer: Conjugation: An Hfr bacterium conjugating with an F- strain allows one to generate a map that is dependent on the passage of the donor chromosome across a conjugation tube.Section: 6.22Copyright © 2012 Pearson Education, Inc.11) Assume that the gene trpA in an auxotrophic strain of E. coli is located at 27 minutes, whereas the gene pyrE is located at 81 minutes.(a) How are minutes arrived at in this context?(b) Present an experimental scheme that would allow you to convert one of the auxotrophic strains to a prototrophic strain.Answer: (a) Minutes are arrived at by a Hfr × F- mating as in the Klug and Cummings text.(b) Hfr (wild type) × F- (auxotroph)Section: 6.212) Distinguish between F+ and F- bacteria.Answer: F+ bacteria contain an F factor or plasmid that is capable of initiating conjugation. F- bacteria contain an F plasmid that possess a portion of the bacterial chromosome.Section: 6.213) What is the consequence of a mutation in the recA gene in bacteria?Answer: The wild-type product of recA is required for bacterial recombination to occur at an appreciable level. Absence of the recA protein diminishes recombination by about 1000-fold.Section: 6.314) How does an auxotroph differ from a prototroph?Answer: Auxotrophs have lost, through mutation, the ability to grow on minimal medium. Prototrophs are capable of growth on minimal medium.Section: 6.115) Bacteriophages that cannot undergo lysogeny but can infect bacteria are called ________.Answer: virulentSection: 6.616) Name the term used to describe the phenomenon in which a bacteriophage genome incorporates its genome into the chromosome of the host.Answer: lysogenySection: 6.617) When a bacteriophage genome incorporates itself into the chromosome of the host, that phage genome is referred to as a(n) ________.Answer: prophageSection: 6.618) What is a form of recombination in bacteria that involves the F plasmid?Answer: conjugationSection: 6.23Copyright © 2012 Pearson Education, Inc.19) What are prototrophs?Answer: Prototrophs are bacteria that can grow on minimal medium and are assumed to be wild type.Section: 6.120) What is the role of the F factor in bacterial recombination?Answer: The F factor confers the capacity to produce a conjugation tube, which functions in conjugation by generating the Hfr and F' recombinant possibilities.Section: 6.221) What is the role of the recBCD genes?Answer: They function in bacterial recombination.Section: 6.322) Present the general structural features of a plasmid and give an example.Answer: circular double-stranded DNA existing autonomously in the bacterial cytoplasm; F factorSection: 6.423) What experimental observation demonstrated that genes are involved in the integration of foreign DNA into the bacterial chromosome?Answer: Mutations allowed identification of rec genes. When such genes were mutated, integration does not occur.Section: 6.324) In general, what two methods are used to grow bacteria in the laboratory?Answer: liquid and semisolid (agar) mediaSection: 6.125) Name three forms of recombination in bacteria.Answer: conjugation, transformation, and transductionSection: 6.2, 6.5, 6.726) Name the typical phases of the bacterial growth cycle in liquid culture medium.Answer: lag, log (exponential), and stationarySection: 6.127) What is a significant difference between a lytic and a lysogenic cycle?Answer: In a lytic cycle, the phage genome does not insert into the bacterial chromosome. In thelysogenic cycle, the phage genome inserts into the bacterial chromosome.Section: 6.64Copyright © 2012 Pearson Education, Inc.28) If two different auxotrophic strains are placed in a liquid medium culture tube, prototrophic strains can sometimes be subsequently recovered. Name several mechanisms by which this is possible.Answer: reverse mutation, genetic suppression, genetic recombination (conjugation, transformation)Section: 6.2, 6.5, 6.729) Describe how different strains of E. coli can reveal different linkage arrangements of genes in