microbiology chapter 12 test bank

microbiology chapter 12 test bank Related

Review microbiology chapter 12 test bank related questions and content

Which of the following has a higher resistance to environmental stresses than the others?

  • A. Bacterial endospores
  • B. Fungal spores
  • C. Enveloped viruses
  • D. Vegetative bacterial cells
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.

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On the territory of a certain region the mass death of rodents was observed. It was assumed that it may be caused by plague agent. What serological reaction should be applied for quick determination of antigen of this epizootic agent?

  • A. Precipitation reaction
  • B. Agglutination reaction
  • C. Reaction of passive hemagglutination
  • D. Bordet-Gengou test
Correct Answer: B

Rationale: The correct answer is B: Agglutination reaction. This is the most suitable serological reaction for the quick determination of the antigen of the epizootic agent causing mass rodent deaths. In agglutination reaction, antibodies cause the clumping of antigens, allowing for easy visual detection of the presence of the specific antigen. This is efficient for rapid diagnosis in cases of suspected infectious diseases like plague.

A: Precipitation reaction is more suitable for identifying soluble antigens, not for quick determination of a specific antigen in this scenario.
C: Reaction of passive hemagglutination is used for measuring the presence of antibodies, not antigens.
D: Bordet-Gengou test is a specific test for the identification of Bordetella pertussis bacterium, not suitable for this scenario.

A relationship in which two organisms benefit is referred to as __________.

  • A. commensalism
  • B. mutualism
  • C. parasitism
  • D. competition
Correct Answer: B

Rationale: The correct answer is B: mutualism. In mutualism, both organisms benefit from the relationship. This is because they provide each other with resources or services that help both parties. In contrast, commensalism (A) is a relationship where one organism benefits while the other is neither helped nor harmed. Parasitism (C) is a relationship where one organism benefits at the expense of the other. Competition (D) is a relationship where both organisms are negatively affected as they compete for limited resources. Therefore, mutualism is the correct answer as it describes a mutually beneficial relationship between two organisms.

A laboratory received a food product that had been taken from the focus of food poisoning and presumably contained botulinum toxin. To identify the type of toxin, the neutralization reaction must be performed on white mice. What biological product is used in this reaction?

  • A. Antitoxic serum
  • B. Normal serum
  • C. Antibacterial serum
  • D. Diagnosticum
Correct Answer: A

Rationale: The correct answer is A: Antitoxic serum. In the neutralization reaction to identify botulinum toxin, antitoxic serum is used to neutralize the toxin in white mice. Antitoxic serum contains antibodies that specifically target and neutralize the botulinum toxin. Normal serum (B) does not contain the necessary antibodies to neutralize the toxin. Antibacterial serum (C) is not effective against toxins like botulinum. Diagnosticum (D) is a general term and does not specifically refer to the biological product required for this reaction.

A family has two children. The younger child is under the year. The child has developed spastic cough attacks. Similar clinical presentation was observed in the elder preschool child one month ago. The doctor suspects pertussis infection. What method enables retrospective diagnostics of this disease?

  • A. Serological
  • B. Biological
  • C. Bacteriological
  • D. Molecular biological
Correct Answer: A

Rationale: The correct answer is A: Serological. Serological testing involves analyzing blood samples for specific antibodies produced in response to the pertussis infection. This method can detect past infections by identifying the presence of antibodies against the pertussis bacteria in the blood. In this case, since the doctor suspects pertussis infection in both children, serological testing can confirm if they have been exposed to the bacteria.

Summary:
B: Biological testing does not specifically target pertussis antibodies in the blood.
C: Bacteriological testing involves culturing bacteria from samples, which may not be as sensitive for retrospective diagnosis.
D: Molecular biological testing focuses on genetic material of the bacteria, which may not provide direct evidence of past infection.

A patient with diarrhea had stool culture revealing non-lactose-fermenting, Gram-negative rods. The bacteria produced gas in a nutrient broth. What is the most likely causative agent?

  • A. Salmonella typhi
  • B. Shigella dysenteriae
  • C. Escherichia coli
  • D. Proteus vulgaris
Correct Answer: D

Rationale: The correct answer is D: Proteus vulgaris. Non-lactose-fermenting, Gram-negative rods that produce gas in a nutrient broth are characteristic of Proteus species. Proteus vulgaris is known for its swarming motility and ability to produce hydrogen sulfide gas. Salmonella typhi and Shigella dysenteriae are Enterobacteriaceae that do not produce gas in a nutrient broth. Escherichia coli is a lactose-fermenting bacterium and would not be expected to produce gas in a nutrient broth.

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