microbiology chapter 12 test bank

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pneumoniae. This bacteria is known for causing pneumonia due to its ability to infect the lungs and cause inflammation leading to pneumonia symptoms. It is a common cause of community-acquired pneumonia. Mycobacterium tuberculosis (B) causes tuberculosis, not pneumonia. Escherichia coli (C) is associated with urinary tract infections and gastrointestinal infections, not pneumonia. Pseudomonas aeruginosa (D) is known to cause infections in immunocompromised individuals but is not a common cause of pneumonia.

Correct Answer: A

Rationale: 1. Vaccination introduces antigens to stimulate immune response. 2. T and B cells are activated to produce memory cells for long-lasting protection. 3. Active immunity develops over time post-vaccination. 4. Choice A is correct as it accurately describes the process and outcomes. 5. Choice B is incorrect as it contradicts the process of active immunity. 6. Choice C is incorrect as the process of active immunity is consistent regardless of the situation. 7. Therefore, the correct answer is A as it aligns with the mechanism and characteristics of artificial active immunity.

Correct Answer: B

Rationale: The correct answer is B: sporadic disease. Infection of several persons without any epidemiological link is considered sporadic because it occurs in a random and isolated manner, with no clear pattern or connection between cases. It is not classified as an epidemic (A) because it does not involve a sudden increase in the number of cases within a specific population. It is also not endemic (C) as endemic diseases are constantly present in a particular region or population. Lastly, it is not a pandemic (D) which refers to a global outbreak affecting a large number of people across different countries.

Correct Answer: D

Rationale: The correct answer is D because all three bacteria listed are capable of producing exotoxins that can cause severe diarrhea. Escherichia coli can produce toxins that lead to diarrhea. Clostridium botulinum produces a neurotoxin causing botulism, which can also result in diarrhea. Vibrio cholerae is known for producing cholera toxin, a potent exotoxin that causes severe watery diarrhea. The other choices are incorrect because each bacterium listed is capable of producing a toxin that can cause diarrhea.

Correct Answer: A

Rationale: The correct answer is A: Bacterial endospores. Bacterial endospores have a higher resistance to environmental stresses due to their unique structure, which includes a tough outer layer that protects the spore from harsh conditions such as heat, chemicals, and radiation. This protective layer allows endospores to remain dormant and survive in unfavorable environments until conditions improve. Summary: B: Fungal spores - While fungal spores can also survive in harsh conditions, they are generally not as resistant as bacterial endospores due to differences in their protective structures. C: Enveloped viruses - Enveloped viruses are susceptible to environmental stresses as their lipid envelope can easily be damaged by heat, chemicals, and other factors. D: Vegetative bacterial cells - Vegetative bacterial cells are more susceptible to environmental stresses compared to endospores, as they do not have the same level of protective mechanisms to survive in unfavorable conditions.