microbiology an introduction tortora test bank

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.

Correct Answer: C

Rationale: Granulomatosis infantiseptica is commonly caused by Listeria monocytogenes, a bacterium known to infect newborns. It can lead to granulomatous lesions in various organs. Staphylococcus aureus and Mycobacterium tuberculosis are not typical causes of this condition in infants. Choice D is incorrect as it suggests all listed bacteria are responsible, which is not accurate. Therefore, the correct answer is C as Listeria monocytogenes is the specific pathogen associated with granulomatosis infantiseptica.

Correct Answer: C

Rationale: The correct answer is C: Replication. In DNA replication, the original DNA molecule is unwound and each strand serves as a template to synthesize a new complementary strand. This results in two identical copies of the original DNA molecule. Translation (A) is the process of synthesizing proteins from mRNA. Transcription (B) is the process of synthesizing mRNA from DNA. Cell division (D) is the process of a cell dividing into two daughter cells, not specifically producing identical DNA copies. Therefore, replication is the correct answer as it specifically refers to the process of copying DNA to produce two identical copies.

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

Correct Answer: B

Rationale: The correct answer is B: Acute purulent lymphadenitis. The symptoms described indicate an acute bacterial infection of the lymph nodes. The presence of painful lymph nodes, erythema, and shiny appearance of the skin overlying the nodes suggest an inflammatory process. The rise in temperature and frequent pulse indicate an active infection. The white-coated tongue may be a sign of systemic involvement. The shaky gait may indicate systemic toxicity. Bubonic plague (A) presents with buboes, not just painful lymph nodes. Lymphogranulomatosis (C) is a type of lymphoma and would not present with these acute bacterial infection symptoms. Anthrax (D) typically presents with a black eschar and is less likely in this context.