ATI RN
microbiology chapter 11 test bank Questions
Question 1 of 5
Streptococcus pyogenes releases:
Correct Answer: B
Rationale: The correct answer is B: Streptolysin. Streptolysin is a toxin released by Streptococcus pyogenes that causes lysis of red blood cells and contributes to the pathogenicity of the bacteria. Enterotoxin (Choice A) is typically produced by Staphylococcus aureus, not Streptococcus pyogenes. Staphylocoagulase (Choice C) is an enzyme produced by Staphylococcus aureus to promote blood clot formation and is not associated with Streptococcus pyogenes. Therefore, the correct answer is B as Streptolysin is the toxin released by Streptococcus pyogenes.
Question 2 of 5
Which of the following is a host-dependent bacterium?
Correct Answer: C
Rationale: The correct answer is C: Rickettsia. Rickettsia is a host-dependent bacterium because it requires living cells of a host organism to survive and replicate. This bacterium is an obligate intracellular pathogen, meaning it cannot grow outside of a host cell. A: Mycoplasma and B: Ureaplasma are not host-dependent as they can grow and reproduce in cell-free environments due to possessing their own unique cell wall structures. D: Micrococcus is a free-living bacterium that can survive and reproduce independently without relying on a host organism.
Question 3 of 5
Infection caused by the genus Candida can be successfully treated with:
Correct Answer: C
Rationale: Step-by-step rationale for why choice C (Nystatin) is the correct answer: 1. Nystatin is an antifungal medication specifically effective against Candida infections. 2. Candida is a type of fungus, not a bacteria targeted by penicillins (choice A) or cephalosporins (choice B). 3. Nystatin works by disrupting the fungal cell membrane, leading to its death. 4. Choice D (None of the above) is incorrect as Nystatin is a suitable treatment option for Candida infections.
Question 4 of 5
Researchers of a bacteriological laboratory examine tinned meat for botulinic toxin. For this purpose a group of mice was injected with an extract of the material under examination and antitoxic antibotulinic serum of A, B, E types. A control group of mice was injected with the same extract but without antibotulinic serum. What serological reaction was applied?
Correct Answer: A
Rationale: The correct answer is A: Neutralization. In this experiment, the researchers used antitoxic antibotulinic serum of different types to neutralize the botulinic toxin in tinned meat extract injected into mice. Neutralization is the process of rendering a toxin harmless by combining it with specific antibodies. The purpose of injecting the antitoxic serum was to neutralize the toxin and prevent it from causing harm to the mice. This serological reaction of neutralization directly aligns with the objective of the experiment. Summary of other choices: B: Precipitation - Precipitation involves the formation of a visible insoluble complex when an antigen reacts with its corresponding antibody. This process was not described in the scenario. C: Complement binding - Complement binding involves the activation of the complement system by antigen-antibody complexes. This was not the main focus of the experiment described. D: Double immune diffusion - This technique is used to detect the presence of specific antigens or antibodies
Question 5 of 5
The one-way transfer of genetic material from a donor cell to a recipient cell by direct cell-to-cell contact is:
Correct Answer: D
Rationale: Conjugation involves direct cell-to-cell contact for the transfer of genetic material, typically through a pilus. This process is well-documented in bacterial genetics. Transformation (A) involves uptake of free DNA from the environment. Transduction (B) is genetic transfer by a viral vector. Replication (C) is the process of producing identical copies of DNA or RNA. Therefore, the correct answer is D (conjugation) as it specifically refers to the one-way transfer of genetic material through direct cell-to-cell contact.