Microbiology Chapter 13 Test Bank

Microbiology Chapter 13 Test Bank Related

Review Microbiology Chapter 13 Test Bank related questions and content

A 9 y.o. child has been taking antibiotics on account of bronchopneumonia for a long time. There appeared pain and burning in the area of mucous membrane of his lips and tongue. Objectively: mucous membrane of lips and tongue has caseous and grey plaques that can be easily removed by a spatula leaving hyperemia foci on their spot. Microscopic examination of the plaques revealed mycelium. What is the most probable diagnosis?

  • A. Candidous cheilitis
  • B. Exfoliative cheilitis
  • C. Leukoplakia
  • D. Contactant allergic cheilitis
Correct Answer: A

Rationale: The most probable diagnosis is A: Candidous cheilitis. Candidous cheilitis is a fungal infection caused by Candida species. In this case, the presence of mycelium on the plaques indicates a fungal infection. The symptoms of pain, burning, and grey plaques that can be easily removed leaving hyperemia are typical for Candidous cheilitis. Choice B (Exfoliative cheilitis) is characterized by scaling and peeling of the lips, not plaques with mycelium. Choice C (Leukoplakia) is a precancerous condition causing white plaques that cannot be easily removed. Choice D (Contactant allergic cheilitis) is an allergic reaction causing inflammation, not fungal plaques.

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A patient with a productive cough and fever had a sputum smear revealing Gram-positive cocci in pairs with a capsule. What is the most likely causative agent?

  • A. Streptococcus pneumoniae
  • B. Klebsiella pneumoniae
  • C. Neisseria meningitidis
  • D. Staphylococcus aureus
Correct Answer: A

Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is the most likely causative agent based on the description of Gram-positive cocci in pairs with a capsule. S. pneumoniae is known for its characteristic morphology and the presence of a capsule, which helps in evading the immune system. It commonly causes pneumonia, especially in patients with a productive cough and fever.

Incorrect choices:
B: Klebsiella pneumoniae typically presents with a mucoid capsule and is associated with pneumonia in immunocompromised individuals.
C: Neisseria meningitidis is a Gram-negative diplococcus and is more commonly associated with meningitis and septicemia.
D: Staphylococcus aureus is a Gram-positive cocci, but it does not typically present in pairs with a capsule and is more commonly associated with skin and soft tissue infections.

Cells that contain a nucleus are __________ cells.

  • A. prokaryotic
  • B. eukaryotic
  • C. anucleate
  • D. haploid
Correct Answer: B

Rationale: The correct answer is B: eukaryotic. Eukaryotic cells have a well-defined nucleus that encloses the genetic material. The nucleus is a distinguishing feature of eukaryotic cells, separating them from prokaryotic cells (choice A) which lack a nucleus. Anucleate cells (choice C) are cells that do not have a nucleus at all. Haploid cells (choice D) contain a single set of chromosomes, but this does not necessarily imply the presence of a nucleus. Therefore, the presence of a nucleus is what categorizes cells as eukaryotic.

As an example of specific human parasites one can name Plasmodium falciparum, human pinworm and some others. The source of parasite invasion is always a human. Such specific human parasites cause the diseases that are called:

  • A. Anthroponoses
  • B. Zoonoses
  • C. Anthropozoonoses
  • D. Infections
Correct Answer: A

Rationale: The correct answer is A: Anthroponoses. This term refers to diseases caused by specific human parasites that are transmitted directly from human to human. In this case, the source of parasite invasion is always a human host. This term specifically describes diseases caused by parasites that exclusively infect humans.

Choice B: Zoonoses refers to diseases that can be transmitted from animals to humans. Choice C: Anthropozoonoses is a combination of zoonoses and anthroponoses, which is not applicable in this scenario. Choice D: Infections is a general term that does not specify the source or type of parasite causing the disease.

Which of the following bacteria is known for causing dental caries (cavities)?

  • A. Streptococcus mutans
  • B. Streptococcus pneumoniae
  • C. Bacillus anthracis
  • D. Clostridium botulinum
Correct Answer: A

Rationale: Step 1: Streptococcus mutans is known for its ability to produce acids that contribute to the demineralization of tooth enamel, leading to dental caries.
Step 2: Streptococcus pneumoniae is a common cause of respiratory infections, not dental caries.
Step 3: Bacillus anthracis causes anthrax, a serious bacterial infection, not dental caries.
Step 4: Clostridium botulinum causes botulism, a severe form of food poisoning, not dental caries.
Summary: Streptococcus mutans is the correct answer as it is specifically associated with causing dental caries, while the other choices are linked to different diseases.

The spores of bacteria can be stained by:

  • A. Methods of Romanovski-Gymsa
  • B. Method of Ziehl-Nielsen
  • C. Method of Moller
  • D. Method of Neisser
Correct Answer: C

Rationale: The correct answer is C: Method of Moller. This method uses malachite green to stain bacterial spores due to their resistance to decolorization. The other choices, A, B, and D, are incorrect because Romanovski-Gymsa is used for staining blood smears, Ziehl-Nielsen is used for acid-fast bacteria, and Neisser is used for staining Neisseria species, not bacterial spores.

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