microbiology test bank

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: B

Rationale: Step-by-step rationale: 1. Sodium is the major cation in the intracellular fluid. 2. It plays a crucial role in maintaining cell volume and transmitting nerve impulses. 3. Potassium is the major cation in the extracellular fluid, not intracellular. 4. Bicarbonate and sulfate are anions and not major cations in intracellular fluid. Summary: Choice B (sodium) is correct as it is the major cation in intracellular fluid, essential for various cellular functions. Choices A, C, and D are incorrect as potassium is extracellular, while bicarbonate and sulfate are anions and not predominant cations in intracellular fluid.

Correct Answer: A

Rationale: The correct answer is A: Candida fungi. Candida fungi are known to cause oral thrush, characterized by whitish spots on the oral mucosa. The presence of gram-positive oval budding cells in the smear preparations is indicative of Candida species. Staphylococci (choice B) are gram-positive cocci, not oval budding cells. Sarcinae (choice C) are gram-positive bacteria that form cuboidal packets, not oval budding cells. Actinomycetes (choice D) are filamentous gram-positive bacteria, not oval budding cells like Candida fungi.

Correct Answer: A

Rationale: The correct answer is A: TRUE. The structures and organs listed are indeed part of the immune system. The lymphatic system transports lymph, lymphoid tissue contains immune cells, lymph nodes filter lymph, thymus matures T-cells, and spleen filters blood and produces immune cells. This comprehensive network is crucial for defending the body against pathogens. Choice B is incorrect as all listed structures are components of the immune system. Choice C is also incorrect as the statement is universally true, not situational. Choice D is incorrect as the correct answer is A.

Correct Answer: D

Rationale: The correct answer is D: BSL4. Ebola viruses are highly infectious and pose a high risk to laboratory workers. BSL4 facilities are designed to handle agents that pose a severe threat to human health and have no available vaccines or treatments. These facilities have strict guidelines for handling infectious agents, including full-body suits, negative air pressure, and decontamination processes to prevent any possible exposure. BSL1, BSL2, and BSL3 are not adequate for handling Ebola viruses due to their lower levels of containment and safety measures.