week 11 final lab Flashcards

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Which of the following best describes the mechanism of action of the antibiotic streptomycin?

It disrupts protein synthesis in non resistant bacteria


Which of the following apply to the development of streptomycin resistance in E. coli?



How will you select and grow a resistant strain of E. coli in this experiment?

Expose a sample of E. coli to streptomycin by inoculating it onto a streptomycin positive plate. Any colonies that grow will carry a mutation for resistance


Let's say you inoculate four agar plates, each containing a different antibiotic (A, B, C, and D), and you add a swab from a lesion taken from a patient. After incubating the plates, you observe that plate A has only a few colonies, while the others all have many colonies. How do you interpret the results?

Bacteria in the patients sample are susceptible to antibiotic A but not B, C and D


How does an antibiotic act as a selective agent in promoting bacterial resistance?

Bacteria with a random mutation that allows resistance to that antibiotic are able to survive exposure and reproduce, passing the resistance mutation on to subsequent generations of bacteria.


Two agar plates, one containing the antibiotic streptomycin and one without antibiotics, are inoculated with E. coli. After incubation, the streptomycin negative plate has many bacterial colonies, while the streptomycin positive plate has only a few colonies. Samples of the colonies from the positive plate are placed on another positive plate, and after incubation many colonies grow. In this experiment, what is the selective agent?

the antibiotic streptomycin