A researcher planned to duplicate the Luria Delbruck fluctuation experiment. This researcher inoculated twenty samples of liquid nutrient media with bacteria from the same colony and let them grow overnight. The next morning the researcher noticed that all but one of the flasks had come open and were ruined. Not wishing to redo the experiment, the researcher spread samples of bacteria from the one intact liquid culture on twenty petri plates that had nutrient agar infused with bacteriophage. What results do you expect the researcher obtained from this experiment?
A) All plates had some bacterial colonies; some plates had more bacterial colonies than others.
B) Some plates had no bacterial colonies; others had varied numbers of colonies.
C) All plates had a similar number of bacterial colonies.
D) Some plates had no bacterial colonies; all of the other plates had a similar number of bacterial colonies.
E) No bacterial colonies formed on any of the plates.
C) All plates had a similar number of bacterial colonies.
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Dysplasia occurs when an abnormal structural change occurs in a cell
Indicate whether the statement is true or false
The accompanying graph shows a growth curve of E. coli growing in a defined medium containing equal molar amounts of glucose and lactose
Based on your knowledge of the regulation of the lac operon, the best explanation of these results is that A) early on, due to the presence of lactose, the bacteria use the lac operon. Glucose is used later. B) the bacteria use both sugars simultaneously. C) the presence of glucose causes the formation of cAMP catabolic repressor protein (CRP) complexes, which shut down the lac operon until the glucose is used up. D) glucose is used first. Once glucose becomes limiting, intracellular cAMP increases, forming cAMP–CRP complexes that activate the lac operon to use lactose. E) early on the glucose binds to the repressor protein lacI and shuts down the lac operon.
The following figure demonstrates the genotypic adaptive landscape of bacteria in me-dia lacking antibiotics
As with all adaptive landscapes, the height of the bars associated with a genotype indicate the fitness of that genotype. The R allele confers resistance to antibiotics, and the C allele compensates for the loss of fitness that the R allele confers in the absence of antibiotics. The rc haplotype lacks both compensation and resistance. Based on this landscape, why are resistance and compensation unlikely to be lost even in the absence of antibi-otics? a. A lack of mutation will prevent the haplotypes from changing. b. Epistasis will maintain haplotype frequencies. c. Haplotype frequencies do not change in Hardy–Weinberg populations. d. RC populations are stuck on a local maxima. e. Bacteria evolve slowly.
As a result of nondisjunction, an individual with Turner syndrome is genotypically XO, lacking one of the sex-determining chromosomes. Taking this into account, the fusion of the gamete containing the extra chromosome with a normal gamete could result in an individual with the genotype
A) XXX. B) XXY. C) XYY. D) A or B E) A, B, or C