Which one of the following contributes to the utility of the strains of Salmonella typhimurium used in the Ames reversion assay?
A. They are highly permeable to test substances.
B. They are defective in DNA repair and, therefore, cannot readily repair damage done by the test substances.
C. It is very straightforward to assay the conversion of their histidine auxotrophy mutations to histidine prototrophy.
D. all of the choices
Answer: D
Microbiology
- Which of the following pairs is not correctly matched?
- Mycoplasmas differ from other bacteria because they
- All of the following are motile; which does not have flagella?
- What should you do if you suspect a patient has tuberculosis?
- Which of the following does not belong with the others?
- Pathogenic bacteria are easily identified because they
- Caulobacter are different from most bacteria because
- Which one of the following does not belong with the others?
- Which of the following pairs is mismatched?
- You have isolated an aerobic gram-positive, endospore-forming bacterium that grows wells on nutrient agar. To which of the following groups does it most likely belong?
- Actinomycetes differ from fungi because actinomycetes
- You have isolated a prokaryotic cell. The first step in identification is a(n)
- Thiobacillus oxidizes inorganic sulfur compounds and reduces CO 2. This bacterium is
- Borrelia is classified as a spirochete because it
- You have isolated a gram-positive rod. What should you do next?
- Salmonella, Shigella, Yersinia, and Serratia are all
- All of the following are gram-positive. Which does not belong with the others?
- Streptomyces differs from Actinomyces because Streptomyces
- Which of the following is the best reason to classify Streptococcus in the Lactobacillales?
- The nonsulfur photosynthetic bacteria use organic compounds as
- Both Beggiatoa and the purple sulfur bacteria use H 2S. These bacteria differ because Beggiatoa
- The bacteria responsible for more infections and more different kinds of infections are
- Which one of the following does not belong with the others?
- A primary difference between cyanobacteria and purple and green phototrophic bacteria is
- All of the following are true about the causative agent of Rocky Mountain spotted fever except