Correct Answer: C

Rationale: The correct answer is C: Obligate aerobes. These bacteria require oxygen for their survival and growth. They utilize oxygen in their metabolic processes and cannot survive in the absence of oxygen. Choice A, obligate anaerobes, cannot survive in the presence of oxygen. Choice B, facultative anaerobes, can switch between aerobic and anaerobic metabolism based on oxygen availability. Choice D, aerotolerant anaerobes, can tolerate the presence of oxygen but do not require it for their growth. Therefore, the most appropriate term for bacteria that require oxygen for survival is obligate aerobes.

Correct Answer: A

Rationale: Step 1: Small, curved Gram-negative bacilli with a monotrichous flagellum point towards a motile bacterium. Step 2: The absence of spores or capsules and preference for alkaline conditions further narrows down the possibilities. Step 3: Vibrio cholerae fits all criteria as it is a curved, motile, Gram-negative bacillus that thrives in alkaline environments. Summary: Escherichia coli is a facultative anaerobe, Salmonella and Shigella are non-flagellated, and all of them can form capsules or spores, unlike Vibrio cholerae.

Correct Answer: C

Rationale: The correct answer is C: Cell wall. Penicillin targets the cell wall of bacteria by inhibiting the formation of peptidoglycan, a crucial component of the cell wall. This weakens the cell wall, leading to bacterial cell lysis. Choice A (DNA) is incorrect because penicillin does not directly target DNA. Choice B (Plasma membrane) is incorrect as penicillin primarily affects the cell wall, not the plasma membrane. Choice D (Ribosomes) is incorrect because penicillin does not target bacterial ribosomes, which are involved in protein synthesis.

Correct Answer: A

Rationale: The correct answer is A because it lists the genera that belong to the family Reoviridae accurately. Orthoreovirus and Rotavirus are well-known genera within the family Reoviridae. Orbivirus is another genus belonging to the same family. Choice B is incorrect because Orthoretrovirus and Retrovirus are not part of the Reoviridae family. Orbfiloviridae is also not a valid genus within this family. Choice C is incorrect because Orthoretrovirus and Retrovirus are not part of the Reoviridae family. Orbivirus is the correct genus but the other two are inaccurate. Choice D is incorrect because Orthoretrovirus and Retrovirus are not part of the Reoviridae family. Orbarenaviridaefiloviridae is not a valid genus within Reoviridae.

Correct Answer: A

Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the botulinum neurotoxin, which causes paralysis by blocking the release of acetylcholine at neuromuscular junctions. Clostridium perfringens causes gas gangrene, not paralysis. Escherichia coli is associated with gastrointestinal infections, not paralysis. Staphylococcus aureus produces enterotoxins causing food poisoning, not paralysis. Therefore, Clostridium botulinum is the correct choice based on its well-known association with paralysis due to botulinum neurotoxin production.