(a) Describe why DNA replication is said to be a semiconservative process. Explain how random mutations such...
Question:
(a) Describe why DNA replication is said to be a semiconservative process. Explain how random mutations such as those in pathogens with a mutator phenotype may arise in the DNA of an organism.(b) Identify a dependent variable in the experiments. Identify the reasoning of the scientists when they tested the number of colonies produced by strains C3-PBB and C6-PBB. The scientists also analyzed the number of colonies produced from each of the environmental and clinical isolate strains when the strains were plated on a growth medium lacking the toxic chemical. Justify this analysis.(c) Based on the data in Figure 1, for each strain describe the relationship between the number of colonies observed and the likely mutation rate of the strain.(d) State the null hypothesis for the experiment whose data are graphed in Figure 2. Provide evidence to support or refute the scientists? claim that more colonies grew in strains C3 and C6 than in the other strains because the genes for proteins that are normally targeted by the toxic chemical contain nucleotides with incorrect bases in the C3 and C6 cells. The scientists additionally determined that the C3 and C6 strains had no decrease in virulence (disease-causing ability) in comparison with the virulence of the other clinical isolate strains and concluded that these two strains have mutator phenotypes. Explain why mutator phenotypes were found only among clinical isolate strains and not among environmental strains.