microbiology test bank

Correct Answer: B

Rationale: The correct answer is B: acidic pH. The reproductive tract's acidic pH serves as a defense mechanism by creating an environment hostile to many pathogens, preventing microbial infection. The acidic pH helps to inhibit the growth and survival of harmful microorganisms. A: Alkaline pH would actually be more favorable for microbial growth as most pathogens thrive in neutral to alkaline pH environments. C: High sugar concentration can actually promote microbial growth as many pathogens feed on sugars. D: High body temperature may help in some cases, but it is not as effective as an acidic pH in preventing microbial infection in the reproductive tract.

Correct Answer: D

Rationale: The correct answer is D: Oral candidiasis. Soor is a term used to describe oral candidiasis, a fungal infection caused by Candida species. This infection presents as white patches on the tongue, inner cheeks, and roof of the mouth. The other choices (A, B, C) refer to different types of fungal infections affecting various parts of the body, not specifically the oral cavity. Therefore, based on the description of soor and its characteristics, the correct answer is D.

Correct Answer: D

Rationale: The correct answer is D, the rabies virus. Rabies virus has the widest infectious spectrum among the given choices because it can infect a wide range of mammals, including humans. This is due to its ability to infect nerve cells and spread throughout the central nervous system. The other choices have more limited infectious spectra. Anthrax bacillus primarily infects herbivores and humans, mumps virus infects mainly humans, and the causative agent of gonorrhea primarily infects humans through sexual contact. Therefore, the rabies virus is the correct answer as it has the broadest range of potential hosts.

Correct Answer: A

Rationale: The correct answer is A: Gram staining. This method is used to differentiate bacteria based on their cell wall composition. In cholera, the causative agent is Vibrio cholerae, which is Gram-negative. By performing Gram staining, the bacteria will appear pink/red under the microscope, confirming the presence of Gram-negative bacteria. Choice B: Neisser's staining is used for staining capsules of bacteria, not suitable for confirming cholera diagnosis. Choice C: Ziehl-Neelsen staining is used for acid-fast bacteria like Mycobacterium tuberculosis, not for confirming cholera diagnosis. Choice D: Burri-Gins staining is not a standard staining method in microbiology and is not relevant for confirming cholera diagnosis.

Correct Answer: D

Rationale: The correct answer is D because enveloped viruses have a lipid bilayer envelope derived from the host cell membrane, which is a complex structure, not exhibiting any specific symmetry. Choice A (cubic symmetry) is incorrect as enveloped viruses do not have any specific geometric shape. Choice B (spiral symmetry) is incorrect as this type of symmetry is typically seen in non-enveloped viruses like helical viruses. Choice C (complex symmetry) is also incorrect as enveloped viruses do not exhibit a specific symmetrical pattern. Therefore, the correct answer is D because enveloped viruses do not have a defined symmetry and can vary in shape and structure.