microbiology an evolving science test bank

Correct Answer: A

Rationale: Rationale: Natural active immunity is indeed active because it involves the activation of lymphocytes by antigens during infection or disease. This process leads to the production of memory cells for long-lasting protection. This distinguishes it from passive immunity, where antibodies are transferred rather than produced by the individual's immune system. Therefore, choice A is correct. Choice B is incorrect because it contradicts the nature of natural active immunity. Choice C is incorrect as the statement is always true for natural active immunity. Choice D is incorrect as there is a correct answer among the given choices.

Correct Answer: B

Rationale: The correct answer is B: Adhesion. Pili are bacterial appendages that help bacteria adhere to surfaces. This is important for colonization and biofilm formation. Choice A (Chemotaxis) is incorrect because chemotaxis is the movement of bacteria in response to chemical stimuli, not the function of pili. Choice C (Nutrient acquisition) is incorrect because pili are not directly involved in obtaining nutrients. Choice D (None of the above) is incorrect as pili do serve a specific purpose, which is adhesion.

Correct Answer: B

Rationale: The correct answer is B: scalp. Tinea capitis is a fungal infection that specifically affects the scalp. This infection is caused by dermatophytes, which thrive in warm and moist environments. It typically presents with symptoms such as scaling, itching, and hair loss on the scalp. Choices A, C, and D are incorrect because tinea pedis (athlete's foot) affects the feet, oral thrush is a fungal infection of the mouth, and tinea manuum affects the hands. By process of elimination and understanding the specific characteristics of tinea capitis, we can determine that the scalp is the correct location for this fungal infection.

Correct Answer: A

Rationale: The correct answer is A: Commensalism. In this relationship, the skin microflora benefits from the host without causing harm or benefitting it. This is evident in the mutualistic interaction where the microflora receive nutrients and a place to live, while the host remains unaffected. Choice B, Infection, is incorrect because it implies harm to the host. Choice C, Parasitism, is also incorrect as it involves one organism benefiting at the expense of the other. Choice D, No correct answer, is not applicable here as Commensalism accurately describes the relationship between the macroorganism and skin microflora.

Correct Answer: A

Rationale: The correct answer is A: Nystatin. Nystatin is specifically used to treat intestinal candidiasis because it targets and eliminates the Candida species responsible for the infection. It is not absorbed systemically, acting only locally in the gastrointestinal tract. Griseofulvin (B) is mainly used to treat fungal skin infections, not intestinal candidiasis. Undecyne (C) is an antifungal agent used for skin infections, not for intestinal candidiasis. Amphotericin B (D) is a potent antifungal agent used for systemic fungal infections, not specifically for intestinal candidiasis.