Which of the following bacteria is responsible for causing peptic ulcers?

Correct Answer: B

Rationale: The correct answer is B: Helicobacter pylori. This bacterium is known to be the primary cause of peptic ulcers by colonizing the stomach lining and causing inflammation. It produces urease enzyme to neutralize stomach acid and has a flagellum for mobility. Escherichia coli (A) is mainly associated with foodborne illnesses. Streptococcus pyogenes (C) causes strep throat and skin infections. Mycobacterium tuberculosis (D) causes tuberculosis, a respiratory infection. Therefore, Helicobacter pylori is the correct choice for peptic ulcers based on its unique characteristics and pathogenicity.

Correct Answer: A

Rationale: The correct answer is A because Fluconazole, Orungal, and Nizoral are antifungal medications commonly used for prevention of fungal infections. Fluconazole is a systemic antifungal agent, Orungal (Itraconazole) is used for various fungal infections, and Nizoral (Ketoconazole) is effective against a wide range of fungal infections. Choices B, C, and D do not contain antifungal medications and are unrelated to preventing fungal infections.

Correct Answer: C

Rationale: Granulomatosis infantiseptica is commonly caused by Listeria monocytogenes, a bacterium known to infect newborns. It can lead to granulomatous lesions in various organs. Staphylococcus aureus and Mycobacterium tuberculosis are not typical causes of this condition in infants. Choice D is incorrect as it suggests all listed bacteria are responsible, which is not accurate. Therefore, the correct answer is C as Listeria monocytogenes is the specific pathogen associated with granulomatosis infantiseptica.

Correct Answer: A

Rationale: The correct answer is A: Vibrio cholerae. This bacterium produces cholera toxin, an exotoxin that causes severe dehydration and diarrhea by increasing the secretion of electrolytes and water in the intestines. Vibrio cholerae is the causative agent of cholera, a disease characterized by profuse watery diarrhea. Choice B, Clostridium tetani, produces tetanospasmin causing tetanus, not dehydration or diarrhea. Choice C, Escherichia coli, can cause diarrhea but rarely severe dehydration. Choice D, Shigella dysenteriae, produces Shiga toxin leading to bloody diarrhea, not severe dehydration.

Correct Answer: B

Rationale: The correct answer is B: prokaryotic. Bacteria are prokaryotic cells because they lack a true nucleus and membrane-bound organelles. They have a simple cell structure with genetic material floating freely in the cytoplasm. Choice A (eukaryotic) is incorrect because eukaryotic cells have a nucleus and membrane-bound organelles. Choice C (diploid) is incorrect as bacteria do not have a defined ploidy level like diploid organisms do. Choice D (haploid) is also incorrect as bacteria do not have a true haploid or diploid state due to their lack of a defined nucleus.