microbiology test bank

Correct Answer: C

Rationale: Step 1: The nucleocapsid is the structure containing the viral genome and the protein capsid. Step 2: The genome carries the genetic material of the virus. Step 3: The capsid is the protein coat that encloses and protects the viral genome. Step 4: Therefore, the correct answer is C: Genome and capsid. Summary: A: Capsid and spikes - Incorrect, spikes are not part of the nucleocapsid. B: Genome and envelop - Incorrect, the envelop is not part of the nucleocapsid. D: Capsid and envelope - Incorrect, the envelope is not part of the nucleocapsid.

Correct Answer: A

Rationale: Step-by-step rationale for choice A: 1. Viruses contain genetic material in the form of nucleic acids (DNA or RNA). 2. Proteins are essential for the structure and function of viral particles. 3. Nucleic acids (genetic material) and proteins are the two main components of viruses. 4. Therefore, choice A (nucleic acid and proteins) is correct. Summary: - Choice B (nucleic acids and lipids) is incorrect as lipids are not a main structural component of viruses. - Choice C (lipids and proteins) is incorrect as nucleic acids are essential components of viruses. - Choice D (proteins and glycoproteins) is incorrect as glycoproteins are a type of protein and not a separate component in viruses.

Correct Answer: A

Rationale: The correct answer is A: T-lymphocytes. Cell-mediated immunity involves the activation of T-lymphocytes, which play a crucial role in recognizing and killing infected cells. T-lymphocytes include cytotoxic T cells, helper T cells, and regulatory T cells, all of which are involved in different aspects of cell-mediated immunity. Monocytes (choice B) are a type of white blood cell involved in phagocytosis but are not the main mediators of cell-mediated immunity. B-lymphocytes (choice C) are involved in humoral immunity, producing antibodies, not cell-mediated immunity. Choice D (A+B+C) is incorrect because cell-mediated immunity is mainly mediated by T-lymphocytes.

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: A

Rationale: The correct answer is A: Entamoeba histolytica. This is because Entamoeba histolytica is known to cause amebic dysentery, leading to chronic diarrhea. The presence of cysts with four nuclei in the stool sample is characteristic of Entamoeba histolytica. Giardia lamblia (choice B) is known to cause diarrhea but does not present with cysts containing four nuclei. Balantidium coli (choice C) is a ciliated protozoan that can cause diarrhea, but it does not have cysts with four nuclei. Trichomonas hominis (choice D) is a non-pathogenic protozoan commonly found in the human colon and is not associated with causing chronic diarrhea or cysts with four nuclei.