microbiology chapter 1 test bank

Correct Answer: D

Rationale: The correct answer is D: commensalism. In commensalism, one organism benefits while the other is neither helped nor harmed. In this relationship, the waste product of one organism serves as a nutrient source for another without affecting the first organism. Mutualism (A) involves both organisms benefiting, competition (B) involves a struggle for resources, and synergism (C) involves cooperative interactions. Commensalism is the only choice where one organism benefits from the waste product of another without any impact on the producer.

Correct Answer: B

Rationale: The correct answer is B: Typhoid fever, Brucellosis. Both Typhoid fever and Brucellosis are bacterial infections that can lead to bacteremia, the presence of bacteria in the bloodstream. In Typhoid fever, the causative agent Salmonella typhi can enter the bloodstream, causing bacteremia. Similarly, Brucellosis, caused by Brucella species, can also result in bacteremia. Choice A is incorrect because bacteremia is not typically observed in Diphtheria. Choice C, Cholera, is caused by a toxin-producing bacterium and does not usually lead to bacteremia. Choice D, Dysentery, is a condition characterized by bloody diarrhea and is primarily caused by parasites or bacteria that typically do not lead to bacteremia.

Correct Answer: C

Rationale: The correct answer is C: ECHO virus infection. ECHO virus is transmitted via the fecal-oral route, meaning the virus is passed from feces to the mouth. This transmission occurs through contaminated food, water, or surfaces. Relapsed fever and spotted fever are generally transmitted by arthropod vectors like ticks. Pertussis, also known as whooping cough, spreads through respiratory droplets. Therefore, the fecal-oral route is not applicable to these diseases.

Correct Answer: D

Rationale: The correct answer is D: Paramyxoviridae. Mumps virus is a member of the Paramyxoviridae family, based on its characteristics such as structure, genome organization, and replication cycle. Paramyxoviruses are enveloped, non-segmented RNA viruses with a helical nucleocapsid. They replicate in the cytoplasm and bud from the host cell membrane. Coronaviridae (A) are a different family of viruses with distinct characteristics. Picornaviridae (B) and Orthomyxoviridae (C) are also different families with unique features that do not match those of the mumps virus.

Correct Answer: A

Rationale: The correct answer is A: BCG vaccine. Step 1: BCG vaccine is specifically designed to protect against tuberculosis, making it the appropriate choice for newborns. Step 2: STI vaccine is for sexually transmitted infections, not tuberculosis. Step 3: EV vaccine is not a recognized vaccine. Step 4: DPT vaccine protects against diphtheria, pertussis, and tetanus, not tuberculosis. In summary, BCG vaccine is the correct choice as it targets tuberculosis specifically, while the other options are designed for different purposes.