B cells are more effective than macrophages in presenting antigens to activate T cells when
A. macrophages are in short supply.
B. antigen concentrations are high.
C. antigen concentrations are low.
D. none of the choices
Answer: C
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