ATI RN
microbiology an introduction 12th edition test bank Questions
Question 1 of 5
The optochin sensitivity test demonstrates:
Correct Answer: B
Rationale: The optochin sensitivity test is used to differentiate Pneumococcal (Streptococcus pneumoniae) from other streptococci. Optochin sensitivity is a characteristic feature of Pneumococcal, as it inhibits its growth. The test involves placing optochin discs on a culture plate and observing the zone of inhibition around the disc for Pneumococcal. Neisseria gonorrhoeae, Staphylococci, and Group A streptococci do not exhibit optochin sensitivity, making them incorrect choices. In summary, the optochin sensitivity test is specific to Pneumococcal, making choice B the correct answer.
Question 2 of 5
Bacteria that have a single polar flagellum at one end are referred to as:
Correct Answer: B
Rationale:
Step-by-step rationale:
1. Monotrichous means having a single flagellum at one end.
2. The term "polar" indicates that the flagellum is located at one end of the bacterium.
3.
Therefore, bacteria with a single polar flagellum are referred to as monotrichous.
4.
Choice A is a typo, as it is the same as the correct answer B.
Summary:
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Choice A is a typo, as it duplicates the correct answer.
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Choice C, amphitrichous, refers to bacteria with a flagellum at each end.
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Choice D, peritrichous, describes bacteria with flagella distributed over the entire surface.
Question 3 of 5
Which statements is NOT CORRECT: Treponema pallidum can be cultivated on:
Correct Answer: A
Rationale: The correct answer is A: Artificial food media. Treponema pallidum is a fastidious bacterium that cannot be cultivated on artificial food media due to its complex nutritional requirements. It can be cultivated on cell lines and intratesticular in rabbits.
Therefore, option A is incorrect. Option B and C are correct.
Question 4 of 5
A wound smear from a patient revealed Gram-positive cocci arranged in clusters. The culture was catalase-positive and coagulase-positive. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus aureus.
1. Gram-positive cocci in clusters suggest staphylococci.
2. Catalase-positive indicates staphylococci since streptococci are catalase-negative.
3. Coagulase-positive further confirms Staphylococcus aureus, distinguishing it from other staphylococci.
Summary: B is incorrect as Streptococcus pyogenes is catalase-negative. C is incorrect as Micrococcus luteus is catalase-negative and coagulase-negative. D is incorrect as Enterococcus faecalis is catalase-negative and coagulase-negative.
Question 5 of 5
Which bacteria are capable of forming endospores?
Correct Answer: B
Rationale: The correct answer is B: Clostridium tetani. Endospores are formed by certain bacteria as a survival mechanism in harsh conditions. Clostridium species, including C. tetani, have the ability to form endospores. Staphylococcus aureus (
A), Neisseria gonorrhoeae (
C), and Escherichia coli (
D) do not produce endospores. Staphylococcus aureus is a gram-positive cocci bacterium, Neisseria gonorrhoeae is a gram-negative diplococci bacterium, and Escherichia coli is a gram-negative rod-shaped bacterium.
Therefore, the correct choice is Clostridium tetani as it is known for its ability to form endospores.