ATI RN
microbiology chapter 12 test bank Questions
Question 1 of 5
Which of the following viruses belong to family Arenaviridae?
Correct Answer: A
Rationale: Step-by-step rationale: 1. Arenaviridae family includes viruses with a segmented genome. 2. Lassa virus has a segmented genome, placing it in the Arenaviridae family. 3. Crimean-Congo hemorrhagic fever virus belongs to the Nairoviridae family, not Arenaviridae. 4. Rabies virus belongs to the Rhabdoviridae family, not Arenaviridae. 5. Epstein-Barr virus belongs to the Herpesviridae family, not Arenaviridae. Summary: A: Lassa virus is correct because it has a segmented genome, characteristic of Arenaviridae. B, C, D: Crimean-Congo hemorrhagic fever virus, Rabies virus, and Epstein-Barr virus belong to different virus families, not Arenaviridae.
Question 2 of 5
What is the mechanism of action of the exotoxin C. Diphtheriae?
Correct Answer: C
Rationale: The correct answer is C: Inhibits protein synthesis. Exotoxin of C. Diphtheriae acts by inhibiting protein synthesis in host cells. This disrupts cellular functions and leads to tissue damage. Choice A is incorrect because acetylcholine release is not affected. Choice B is incorrect as it does not involve neurotransmitters. Choice D is incorrect as the exotoxin does have a specific mechanism.
Question 3 of 5
Microscopy of a sputum smear from a pneumonia patient revealed Gram-positive diplococci with pointed ends surrounded by a capsule. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Streptococcus pneumoniae. 1. Gram-positive diplococci with pointed ends: characteristic morphology of Streptococcus pneumoniae. 2. Surrounded by a capsule: S. pneumoniae is encapsulated, important for virulence. 3. Klebsiella pneumoniae (B) is a Gram-negative rod, Neisseria meningitidis (C) is a Gram-negative diplococcus, and Staphylococcus aureus (D) is a Gram-positive cocci in clusters, not diplococci.
Question 4 of 5
A family has two children. The younger child is under the year. The child has developed spastic cough attacks. Similar clinical presentation was observed in the elder preschool child one month ago. The doctor suspects pertussis infection. What method enables retrospective diagnostics of this disease?
Correct Answer: A
Rationale: The correct answer is A: Serological. Serological testing involves analyzing blood samples for specific antibodies produced in response to the pertussis infection. This method can detect past infections by identifying the presence of antibodies against the pertussis bacteria in the blood. In this case, since the doctor suspects pertussis infection in both children, serological testing can confirm if they have been exposed to the bacteria. Summary: B: Biological testing does not specifically target pertussis antibodies in the blood. C: Bacteriological testing involves culturing bacteria from samples, which may not be as sensitive for retrospective diagnosis. D: Molecular biological testing focuses on genetic material of the bacteria, which may not provide direct evidence of past infection.
Question 5 of 5
A patient with diarrhea had stool culture revealing non-lactose-fermenting, Gram-negative rods. The bacteria produced gas in a nutrient broth. What is the most likely causative agent?
Correct Answer: D
Rationale: The correct answer is D: Proteus vulgaris. Non-lactose-fermenting, Gram-negative rods that produce gas in a nutrient broth are characteristic of Proteus species. Proteus vulgaris is known for its swarming motility and ability to produce hydrogen sulfide gas. Salmonella typhi and Shigella dysenteriae are Enterobacteriaceae that do not produce gas in a nutrient broth. Escherichia coli is a lactose-fermenting bacterium and would not be expected to produce gas in a nutrient broth.