microbiology an introduction tortora test bank

Correct Answer: C

Rationale: The correct answer is C: Campylobacter jejuni. This bacterium is Gram-negative and comma-shaped, commonly causing respiratory infections. Vibrio cholerae (A) causes cholera, not respiratory infections. Shigella dysenteriae (B) causes dysentery, not respiratory infections. Helicobacter pylori (D) is associated with gastric ulcers, not respiratory infections. Therefore, Campylobacter jejuni is the most likely causative agent based on the given information.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Family Retroviridae is known for having a single-stranded RNA genome. 2. The (-) sign indicates that the RNA strand is negative-sense. 3. Therefore, the correct answer A, "Their capsid consists of two copies of ssRNA(-)," is accurate. Summary: - Choice B is incorrect because Retroviridae have simple type of symmetry. - Choice C is incorrect as Retroviridae are not enveloped viruses. - Choice D is incorrect because Retroviridae are enveloped viruses.

Correct Answer: D

Rationale: The correct answer is D: Exanthematous rash. Erythema infectiosum, also known as fifth disease, is characterized by a distinctive rash on the cheeks that looks like a "slapped cheek." This rash then spreads to the rest of the body, resulting in a lace-like rash (exanthem). Swelling of salivary glands (choice A) is not a typical symptom of erythema infectiosum. Diarrhea (choice B) and hepatitis (choice C) are also not associated with this condition. Therefore, the most characteristic clinical symptom of erythema infectiosum is the exanthematous rash.

Correct Answer: A

Rationale: The correct answer is A: Botulism. The symptoms described, such as ptosis, mydriasis, anisocoria, dry mouth, and absent gag reflex, are classic signs of botulism. Botulism is caused by the bacterium Clostridium botulinum, commonly found in improperly preserved canned foods. The progression from gastrointestinal symptoms to neurological symptoms, like double vision and difficulty swallowing, is characteristic of botulism due to the toxin's effect on neuromuscular transmission. Poliomyelitis primarily affects the motor neurons and presents with different symptoms. Food toxicoinfection typically involves gastrointestinal symptoms and does not manifest with the neurological findings seen in this case. Acute ischemic stroke presents with sudden onset neurological deficits due to impaired blood flow to the brain, which is not consistent with the gradual progression of symptoms in this scenario.

Correct Answer: C

Rationale: The correct answer is C because disinfectants are non-selective and can harm a wide range of microbial cells. Disinfectants work by disrupting cell membranes, proteins, and nucleic acids, affecting both harmful and beneficial microorganisms. Choices A and B are incorrect because disinfectants are designed to be potent and non-selective. Choice D is incorrect because the effects of disinfectants are often permanent and irreversible on microbial cells.