Microbiology Chapter 12 Test Bank

Microbiology Chapter 12 Test Bank Related

Review Microbiology Chapter 12 Test Bank related questions and content

On the 8th day since the patient was inoculated with antitetanic serum because of dirty wound of his foot he has developed rising temperature up to 380% , pains in the joints, rash and itch. The blood tests revealed leukopenia and thrombocytopenia. Allergic reaction of what type has developed in this case?

  • A. Anaphylactic
  • B. Cytotoxic
  • C. Delayed type of hypersensitivity
  • D. Immunocomplex
Correct Answer: D

Rationale: The correct answer is D: Immunocomplex. In this case, the patient's symptoms of fever, joint pains, rash, and itch along with leukopenia and thrombocytopenia indicate a serum sickness reaction. This is a type III hypersensitivity reaction where antigen-antibody complexes deposit in tissues, leading to inflammation and tissue damage. The symptoms typically occur 1-2 weeks after exposure to the antigen. Anaphylactic reaction (choice A) is immediate and involves IgE antibodies. Cytotoxic reaction (choice B) involves destruction of cells by antibodies. Delayed hypersensitivity (choice C) usually takes 48-72 hours to develop and involves T-cells. Therefore, the correct answer is D as it aligns with the symptoms and timeline of a type III hypersensitivity reaction.

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The presence of flagella in bacterial cell represents:

  • A. H-antigen
  • B. O-antigen
  • C. K-antigen
  • D. None of the above
Correct Answer: A

Rationale: The presence of flagella in a bacterial cell represents the H-antigen. Flagella are protein structures on the cell surface that play a role in bacterial motility. The H-antigen refers to the flagellar antigen, which is involved in immune responses and bacterial identification. Option A is correct because flagella are specifically associated with the H-antigen.

Summarily, choices B and C are incorrect because the O-antigen and K-antigen are associated with lipopolysaccharide and capsule antigens, respectively, not flagella. Option D is incorrect as well because the correct association is with the H-antigen.

Bacteria that prefer high levels of salt in their growing environment are referred to as:

  • A. calciphiles
  • B. halophiles
  • C. osmophiles
  • D. mesophiles
Correct Answer: B

Rationale: The correct answer is B: halophiles. Halophiles are bacteria that thrive in high salt environments. They have adapted to survive and grow in areas with high salt concentrations. This preference for high salt levels is what distinguishes halophiles from other types of bacteria.

A: Calciphiles are bacteria that prefer high levels of calcium.
C: Osmophiles are bacteria that thrive in environments with high sugar concentrations.
D: Mesophiles are bacteria that prefer moderate temperature ranges for growth.

In summary, the correct term for bacteria that prefer high levels of salt in their growing environment is halophiles, making choices A, C, and D incorrect in this context.

Artificial active immunity occurs after a vaccination: injecting or taking antigens by mouth. Takes time for T and B cells to be activated but gives relatively long lasting:

  • A. TRUE
  • B. FALSE
  • C. Both answers can be correct depending on the given situation
  • D. None of the above
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.

Which bacterium is known for causing food poisoning due to its production of enterotoxins?

  • A. Staphylococcus aureus
  • B. Clostridium botulinum
  • C. Salmonella enterica
  • D. Vibrio cholerae
Correct Answer: A

Rationale: The correct answer is A: Staphylococcus aureus. This bacterium causes food poisoning by producing enterotoxins that lead to symptoms like nausea and vomiting. Staphylococcus aureus can survive in various food items and multiply rapidly, producing toxins that are heat-stable. Clostridium botulinum causes botulism due to neurotoxins, not enterotoxins. Salmonella enterica causes gastrointestinal infections, not primarily food poisoning. Vibrio cholerae causes cholera by producing a toxin that leads to severe watery diarrhea and dehydration, not enterotoxins like Staphylococcus aureus.

The bacterial component targeted by penicillin is:

  • A. DNA
  • B. Plasma membrane
  • C. Cell wall
  • D. Ribosomes
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.

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