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  • Question
  • Cholera toxin is an A-B type toxin in which the B portions bind to a receptor on a host cell and the A portion enters the cell to cause


  • Options
  • A. ADP ribosylation of adenylate cyclase that stops production of cAMP
  • B. ADP ribosylation of a G protein that locks it into an active form that stimulates adenylate cyclase to make cAMP
  • C. cleavage of rRNA that results in disruption of ribosome function
  • D. ADP ribosylation of guanylate cyclase that stimulates production of cGMP

  • Correct Answer
  • ADP ribosylation of a G protein that locks it into an active form that stimulates adenylate cyclase to make cAMP 


  • Microorganisms and Disease problems


    Search Results


    • 1. The "A" subunit of diphtheria toxin

    • Options
    • A. binds host cell receptors found on heart cells
    • B. cause ADP ribosylation of a factor involved in protein synthesis
    • C. forms cAMP that leads to fluid accumulation
    • D. lysis macrophages with the release of cytokines
    • Discuss
    • 2. The influenza vaccine is administered each year because

    • Options
    • A. mutations in the viral hemagglutinin may allow the virus to evade the immune response elicited by previous vaccines
    • B. it is a polysaccharide vaccine that does not confer long-term protection
    • C. the vaccine is sufficiently toxic to make it necessary to administer only a small amount at any one time
    • D. none of the above
    • Discuss
    • 3. Which is not a major defense mechanism in the stomach?

    • Options
    • A. Proteolytic enzymes
    • B. Low pH
    • C. Dense normal flora
    • D. All of these
    • Discuss
    • 4. Which of the following is true regarding anthrax?

    • Options
    • A. Anthrax is caused by a virus
    • B. Anthrax is highly contagious
    • C. Inhalation anthrax and cutaneous anthrax are caused by separate strains of Bacillus anthracis
    • D. Inhalation Anthrax requires infection with a large number of spores
    • Discuss
    • 5. All infections do not cause fever and all fevers are not due to infections which of the following is an example of non-infections cause of fever?

    • Options
    • A. Typhoid
    • B. Chicken pox
    • C. Rheumatic disease
    • D. Malaria
    • Discuss
    • 6. The process of Gram staining is based on the ability of bacterial cell wall

    • Options
    • A. to retain the safranin dye
    • B. to retain the crystal violet dye during solvent treatment.
    • C. to retain part of both dyes
    • D. none of above
    • Discuss
    • 7. Which of the following(s) show(s) positive results for phenylalanine deaminase test?

    • Options
    • A. Providencia
    • B. Proteus
    • C. Morganella
    • D. All of these
    • Discuss
    • 8. The gram-negative organisms is

    • Options
    • A. Actinomyces
    • B. Bacillus
    • C. Clostridium
    • D. None of these
    • Discuss
    • 9. The primary stain of Gram's method is

    • Options
    • A. safranin
    • B. phenolpthalene
    • C. crystal violet
    • D. methyl red
    • Discuss
    • 10. Which of the following(s) is/ are oxidase-positive bacteria?

    • Options
    • A. Vibrio
    • B. Neisseria
    • C. Pseudomonas
    • D. All of these
    • Discuss


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