microbiology chapter 14 test bank

Correct Answer: B

Rationale: The correct answer is B: Linnaeus. Linnaeus developed the binomial system of nomenclature in the 18th century. This system uses a two-part naming system consisting of the genus and species name to classify and identify organisms. Linnaeus's contribution revolutionized the way organisms are named and classified in the field of biology. Other choices are incorrect as Pasteur is known for his work in microbiology, Martini is not associated with the development of binomial nomenclature, and Jenner is known for developing the smallpox vaccine.

Correct Answer: A

Rationale: The correct answer is A: Complex. Poxviruses have a complex nucleocapsid symmetry due to their unique structure with multiple layers of proteins and genetic material. Isohedral symmetry (B) refers to a regular polyhedron shape, which is not characteristic of poxviruses. Helical symmetry (C) is found in viruses like tobacco mosaic virus, not poxviruses. "All of the above" (D) is incorrect because poxviruses do not exhibit isohedral or helical symmetry.

Correct Answer: C

Rationale: The correct answer is C: S.aureus. Stomatitis is commonly caused by S.aureus due to its ability to form clusters of oval polymorphous Gram-positive microorganisms. S.aureus is known to colonize the oral mucous membrane and can cause infections, especially after prolonged antibiotic use. Explanation for other choices: A: С.albicans - Candida albicans is a fungus commonly associated with oral thrush, not typically causing stomatitis. B: C.perfringens - Clostridium perfringens is a bacterium associated with food poisoning and gas gangrene, not commonly causing stomatitis. D: S.pyogenes - Streptococcus pyogenes is known to cause strep throat and skin infections, but not typically associated with stomatitis.

Correct Answer: A

Rationale: The correct answer is A: Ziehl-Neelsen staining method. This method is used to detect acid-fast bacteria like Mycobacterium tuberculosis. Step-by-step rationale: 1. Acid-fast bacteria resist decolorization with acid-alcohol. 2. The red bacilli seen in the smear indicate acid-fast bacteria. 3. Ziehl-Neelsen stain uses carbol fuchsin to stain acid-fast bacteria red. 4. The blue background is likely the counterstain methylene blue. Incorrect choices: B: Gram stain is for categorizing bacteria into Gram-positive or Gram-negative, not specific for acid-fast bacteria. C: Giemsa stain is used for blood films and detecting parasites, not acid-fast bacteria. D: Neisser stain is not a standard microbiological staining method.

Correct Answer: A

Rationale: The correct answer is A: Treponema pallidum. This bacterium is responsible for causing syphilis due to its unique spiral shape and ability to penetrate intact mucous membranes. It is transmitted through sexual contact or from mother to child during pregnancy. Neisseria gonorrhoeae causes gonorrhea, Chlamydia trachomatis causes chlamydia, and Escherichia coli is a common bacterium found in the gut and not associated with syphilis. Treponema pallidum's specific characteristics and mode of transmission distinguish it from the other choices, making it the correct answer.