Microbiology An Evolving Science Test Bank

Correct Answer: C

Rationale: The correct answer is C: Tuberculosis. Granulomas with lymphocytes and macrophages containing Virchow's cells (large cells with fat inclusions containing microorganisms) are classic findings in tuberculosis. Leprosy (A) typically presents with granulomas but with different histopathological features. Syphilis (B) does not usually form granulomas in the skin. Rhinoscleroma (D) is a chronic bacterial infection characterized by nodular lesions but does not typically involve Virchow's cells as seen in tuberculosis.

Correct Answer: C

Rationale: Plasmids often carry antibiotic resistance genes, making choice C correct. Plasmids are circular DNA structures, not linear (A). They are found in both gram-positive and gram-negative bacteria, not exclusively in gram-positive bacteria (B). Plasmids are separate from the bacterial chromosome, not part of it (D). Therefore, choice C is the correct answer.

Correct Answer: B

Rationale: The correct answer is B because in immune reactions, a large lattice is formed when antigens and antibodies are in optimal proportion. This optimal ratio allows for the formation of a strong antigen-antibody complex, leading to the aggregation of immune complexes into large lattice structures. When antibodies are in excess (choice A), there may not be enough antigens to form a stable lattice. Similarly, when antigens are in excess (choice C), there may be insufficient antibodies to form a strong lattice. Choice D is incorrect because the optimal proportion of antigens and antibodies is crucial for the formation of large lattices in immune reactions.

Correct Answer: B

Rationale: The correct answer is B: Penicillin. Penicillin is the drug of first choice for treating syphilis due to its effectiveness in eradicating the bacterium Treponema pallidum, which causes syphilis. It is the most reliable treatment with well-established efficacy. Gentamicin (A), ciprofloxacin (C), and chloramphenicol (D) are not recommended for treating syphilis as they are not effective against the specific bacteria causing the infection. Penicillin remains the gold standard for syphilis treatment.

Correct Answer: D

Rationale: The correct answer is D: nonproprietary. The generic name of a drug is the official, nonproprietary name given to a drug by an organization such as the U.S. Food and Drug Administration (FDA). This name is not owned by any specific company and is used universally to identify the drug's active ingredient. The generic name helps to communicate the specific medication being prescribed and allows for cost-effective options for consumers. A: Trade name refers to the brand name given to a drug by a pharmaceutical company. B: Proprietary name is another term for the trade name, specific to the company that produces the drug. C: Chemical name refers to the exact chemical composition of the drug, which may not be user-friendly or easily recognized by healthcare professionals or consumers.