mastering microbiology test bank

Correct Answer: C

Rationale: The correct answer is C: Adhesion and immune evasion. Bacterial capsules serve as a protective layer that aids in adhesion to surfaces and host cells, allowing bacteria to colonize and evade the immune system. This function is crucial for bacterial survival and pathogenicity. Choices A and D are incorrect because energy production and DNA replication are not primary functions of bacterial capsules. Choice B is incorrect because while bacterial capsules do provide some protection from desiccation, their primary function lies in adhesion and immune evasion.

Correct Answer: A

Rationale: Step-by-step rationale for answer A: 1. Pseudomonas aeruginosa is known to cause burn wounds infections due to its ability to survive in moist environments. 2. It can cause severe pneumonia in patients with cystic fibrosis due to its resistance to antibiotics and ability to form biofilms. 3. It is a common cause of nosocomial infections in hospitals due to its ability to colonize medical equipment and surfaces. Summary of other choices: B. Pseudomonas aeruginosa typically does not cause food poisoning, as it is not a common pathogen associated with foodborne illnesses. C. Bacterial pharyngitis is usually caused by Streptococcus pyogenes, not Pseudomonas aeruginosa, making this choice incorrect. D. None of the above is incorrect as Pseudomonas aeruginosa is associated with specific infections mentioned in option A.

Correct Answer: A

Rationale: Flagella are the correct answer because they are long, whip-like structures that aid in bacterial movement towards or away from chemical stimuli. They rotate like propellers, allowing the bacterium to navigate its environment. Pili are used for attachment, not movement. Capsules are involved in protection and adherence, not chemotaxis. Fimbriae help in attachment to surfaces, not in movement towards stimuli.

Correct Answer: A

Rationale: The correct answer is A, Anthrax bacillus, because it has the widest infectious spectrum among the options provided. Anthrax bacillus can infect a wide range of hosts, including humans and various animals. It is known for its ability to survive in different environments and cause disease through various routes of exposure. In contrast, choices B, C, and D have more limited infectious spectra. Mumps virus primarily infects humans, the causative agent of gonorrhea mainly affects humans through sexual contact, and the rabies virus typically infects mammals through bites from infected animals. Therefore, Anthrax bacillus is the correct choice due to its broader range of hosts and modes of transmission compared to the other options.

Correct Answer: B

Rationale: Step-by-step rationale for choice B being correct: 1. The conclusion should be based on evidence or observations. 2. "Doubtful" suggests uncertainty, indicating lack of definitive safety. 3. Choice A is too absolute without considering potential risks. 4. Choice C uses extreme language without proper evidence. 5. Choice D is overly definitive without considering varying levels of contamination. Therefore, choice B is the most reasonable conclusion.