microbiology test bank

Correct Answer: C

Rationale: Rationale: 1. Both Clostridium botulinum and Bacillus anthracis are known to form spores. 2. Spore formation is a mechanism for survival in harsh conditions. 3. Both bacteria are capable of causing severe diseases in humans. Summary: - Choice A and B are incorrect because each bacteria listed is capable of spore formation. - Choice D is incorrect as both bacteria mentioned can form spores to survive extreme conditions.

Correct Answer: A

Rationale: Rationale: 1. Epstein-Barr virus causes infectious mononucleosis due to primary infection. 2. Certain types of cancer, such as Burkitt lymphoma and nasopharyngeal carcinoma, are associated with Epstein-Barr virus through oncogenic mechanisms. 3. Chickenpox and shingles are caused by varicella-zoster virus (HHV3). 4. Roseola infantum is caused by human herpesvirus 6 (HHV6). Summary: Choice A is correct as Epstein-Barr virus is linked to infectious mononucleosis and specific cancers. Choices B, C, and D are incorrect as they are caused by different herpesviruses.

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: D

Rationale: The correct answer is D, Klebsiella pneumoniae. Klebsiella pneumoniae is a fermentative gram-negative rod, which means it can ferment sugars. In contrast, Pseudomonas aeruginosa, Acinetobacter baumannii, and Stenotrophomonas maltophilia are non-fermentative gram-negative rods. These organisms do not ferment sugars for energy production. Therefore, Klebsiella pneumoniae is the only fermentative organism among the choices, making it the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Isoniazid. Isoniazid is a first-line drug for treating active pulmonary tuberculosis due to its high efficacy and low toxicity. It works by inhibiting the synthesis of mycolic acids in the bacterial cell wall. Sulfalen, Cyclocerine, and Ethionamide are not first-line drugs for tuberculosis. Sulfalen is used for urinary tract infections, Cyclocerine for drug-resistant tuberculosis, and Ethionamide as a second-line drug for multidrug-resistant tuberculosis. Therefore, Isoniazid is the most appropriate initial choice for treating active focal pulmonary tuberculosis.