microbiology an introduction tortora test bank

microbiology an introduction tortora test bank Related

Review microbiology an introduction tortora test bank related questions and content

During the skill-building session in microbiology the students need to stain the prepared and fixed sputum smears obtained from a tuberculosis patient. What staining technique should be used in this case?

  • A. Gram
  • B. Giemsa
  • C. Ziehl-Neelsen
  • D. Burri
Correct Answer: C

Rationale: The correct staining technique for sputum smears obtained from a tuberculosis patient is Ziehl-Neelsen staining. This technique uses carbol fuchsin dye to stain the acid-fast bacteria, such as Mycobacterium tuberculosis, red. Here's a step-by-step rationale:
1. Ziehl-Neelsen staining is specifically designed to detect acid-fast bacteria like Mycobacterium tuberculosis.
2. Carbol fuchsin dye is used to penetrate the mycolic acid layer in the cell wall of the bacteria, making them resistant to decolorization.
3. Acid-alcohol is used as a decolorizer to remove the stain from non-acid-fast bacteria.
4. Methylene blue is used as a counterstain to visualize non-acid-fast bacteria in blue.
Therefore, Ziehl-Neelsen staining is the most appropriate technique for identifying Mycobacterium tuberculosis in sputum smears.
Other choices like Gram, Giemsa, and

You may also like to solve these questions

The degree or extent of disease-evoking power that a microorganism has is referred to as:

  • A. virulence
  • B. strength
  • C. resistance
  • D. competence
Correct Answer: A

Rationale: The correct answer is A: virulence. Virulence refers to the degree or extent of disease-evoking power that a microorganism possesses. This term specifically describes the ability of a microorganism to cause disease in a host. It is a crucial factor in understanding the pathogenicity of different microorganisms.

Choice B: strength is incorrect because it does not specifically relate to the disease-causing potential of a microorganism. Choice C: resistance refers to the ability of an organism to withstand the effects of a particular agent, such as a drug or environmental factor. Choice D: competence is not directly related to the disease-causing ability of a microorganism, but rather refers to the ability of an organism to perform a specific function effectively.

A 23-year-old man developed a perforation in his hard palate, a dense formation with clear margins was detected in this area. After a surgery, microscopy of excised formation shows there a large focus of caseous necrosis surrounded with a granulation tissue with endovasculitis and a cellular infiltration consisting of lymphocytes and epithelioid cells with predominance of plasma cells. What is the most likely disease in this case?

  • A. Syphilis
  • B. Tuberculosis
  • C. Leprosy
  • D. Scleroma
Correct Answer: B

Rationale: The correct answer is B: Tuberculosis. The case describes a man with a perforation in the hard palate and features of caseous necrosis with granulation tissue, endovasculitis, and a cellular infiltration mainly of lymphocytes, epithelioid cells, and plasma cells. These findings are classic for tuberculosis infection, commonly seen in extrapulmonary sites like the oral cavity. Syphilis (choice A) typically presents with a painless ulcer and different histopathological features. Leprosy (choice C) presents with granulomas containing foamy macrophages. Scleroma (choice D) is caused by Klebsiella rhinoscleromatis and presents with chronic granulomatous inflammation.

Which of the following viruses belong to the family Herpesviridae?

  • A. Epstein-Barr virus
  • B. Poxvirus
  • C. SARS
  • D. HIV
Correct Answer: A

Rationale: Step-by-step rationale for the correct answer (A: Epstein-Barr virus):
1. Epstein-Barr virus is a member of the Herpesviridae family, known for causing infectious mononucleosis.
2. Members of Herpesviridae have double-stranded DNA genomes and enveloped virions.
3. They establish latent infections in host cells and can reactivate periodically.
4. Poxvirus (B) belongs to the Poxviridae family, not Herpesviridae.
5. SARS (C) is caused by a coronavirus, not a herpesvirus.
6. HIV (D) belongs to the Retroviridae family, not Herpesviridae.

Summary: The correct answer is A because Epstein-Barr virus is a member of the Herpesviridae family, exhibiting specific characteristics distinct from the other choices.

Genus Rickettsia representatives are characterized by:

  • A. Gram-positive cell wall
  • B. High resistance to external environment factors
  • C. Intracellular parasitism
  • D. None of the above
Correct Answer: C

Rationale: The correct answer is C: Intracellular parasitism. Genus Rickettsia representatives are known for their ability to live and replicate inside the host's cells, making them obligate intracellular parasites. This characteristic distinguishes them from other bacteria.
A: Gram-positive cell wall is incorrect because Rickettsia have a gram-negative cell wall.
B: High resistance to external environment factors is incorrect because Rickettsia are sensitive to environmental conditions and require specific host cells for survival.
D: None of the above is incorrect because Rickettsia do exhibit the characteristic of intracellular parasitism.

Bacterial families have general:

  • A. Morphologic features
  • B. Geographic features
  • C. Historical features
  • D. Physiologic features
Correct Answer: A

Rationale: The correct answer is A: Morphologic features. Bacterial families are classified based on their morphologic features such as shape, size, and arrangement. This classification helps in identifying and studying different bacterial species. Choice B, Geographic features, is incorrect as bacterial classification is not based on their geographic distribution. Choice C, Historical features, is incorrect as it does not play a role in the classification of bacterial families. Choice D, Physiologic features, is also incorrect as physiological characteristics are used for further classification within bacterial families, not as a general characteristic.

Copyright © 2025 Nokea. All rights reserved.