ATI RN
microbiology an introduction 13th edition test bank Questions
Question 1 of 9
Which bacteria produce a toxin that causes the disease botulism?
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. This bacterium produces the neurotoxin responsible for botulism. Clostridium perfringens causes gas gangrene, not botulism. Escherichia coli and Salmonella enterica are not associated with botulism. Clostridium botulinum is the only bacterium known to produce the toxin causing botulism.
Question 2 of 9
The only bacteria that have sterols in their cytoplasmic membrane are:
Correct Answer: D
Rationale: The correct answer is D: Mycoplasma. Mycoplasma is the only bacteria among the choices that have sterols in their cytoplasmic membrane. This feature helps stabilize their membrane structure due to the lack of a cell wall. Legionella (A), Bacillus (B), and Rickettsia (C) do not contain sterols in their cytoplasmic membrane. Legionella has a unique lipid composition, Bacillus has peptidoglycan in its cell wall, and Rickettsia is an intracellular parasite lacking sterols in its membrane.
Question 3 of 9
Which bacteria are responsible for causing foodborne illnesses?
Correct Answer: D
Rationale: The correct answer is D, "All of the above," because all three bacteria (Salmonella enterica, Clostridium botulinum, Escherichia coli) are known to cause foodborne illnesses. Salmonella causes symptoms like diarrhea, fever, and abdominal cramps. Clostridium botulinum produces a toxin leading to botulism, a severe illness affecting the nervous system. Escherichia coli strains like E. coli O157:H7 can cause food poisoning with symptoms such as bloody diarrhea. Therefore, all the listed bacteria can cause foodborne illnesses due to their ability to contaminate food and infect individuals.
Question 4 of 9
Poxviruses are largest viruses, almost visible on light microscope
Correct Answer: A
Rationale: The correct answer is A: TRUE. Poxviruses are indeed the largest viruses known, ranging from 200-450 nm in size, which is close to the resolution limit of a light microscope. This makes them almost visible under a light microscope. Explanation: 1. Poxviruses have complex structures and are among the largest viruses. 2. Light microscopes have a resolution limit of around 200 nm. 3. Poxviruses fall within the size range that is close to the resolution limit of a light microscope. 4. Therefore, poxviruses are almost visible under a light microscope. Summary: Choice B is incorrect because poxviruses are indeed large enough to be almost visible under a light microscope. Choice C is incorrect as it implies uncertainty, but poxviruses are consistently close to the resolution limit of a light microscope. Choice D is incorrect as the size of poxviruses being almost visible under a light microscope is a factual statement, not dependent
Question 5 of 9
The correct sequence of stages in the multiplication of animal viruses is
Correct Answer: A
Rationale: The correct sequence of stages in the multiplication of animal viruses is as follows: 1. Adsorption: Virus attaches to host cell. 2. Penetration: Virus enters host cell. 3. Uncoating: Viral genetic material is released. 4. Replication: Viral genetic material replicates. 5. Assembly: New viral particles are assembled. 6. Release: New viral particles are released from the host cell. Choice A is correct as it follows the correct chronological order of virus multiplication stages. Choice B is incorrect as it has the wrong order of penetration and adsorption. Choice C is incorrect as it has the wrong order of adsorption, uncoating, and penetration. Choice D is incorrect as it has the wrong order of penetration and uncoating.
Question 6 of 9
A businessman came to India from South America. On examination the physician found that the patient was suffering from sleeping-sickness. What was the way of invasion?
Correct Answer: B
Rationale: The correct answer is B: As a result of mosquito's bites. Sleeping sickness, also known as African trypanosomiasis, is caused by the parasite Trypanosoma transmitted by tsetse flies, not mosquitoes. Tsetse flies are primarily found in Africa, not South America. Choice A is incorrect as bug bites do not transmit sleeping sickness. Choice C is incorrect as contaminated fruits and vegetables do not transmit the disease. Choice D is incorrect as dirty hands do not play a role in the transmission of sleeping sickness.
Question 7 of 9
A sample of a finished dosage form was found to be contaminated with some microorganisms exhibiting the following properties: greenish fluorescent colonies of gram-negative nonsporeforming bacilli that grew on the medium for the detection of pyocyanin. The bacilli release the bluegreen pigment into the medium. What microorganisms contaminated the finished dosage form?
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. Pseudomonas aeruginosa is a gram-negative bacilli that produce pyocyanin, a blue-green pigment. The presence of greenish fluorescent colonies of gram-negative nonsporeforming bacilli that release blue-green pigment matches the characteristics of Pseudomonas aeruginosa. Now, let's analyze the other choices: B: Enterobacteriaceae - While some Enterobacteriaceae can be gram-negative bacilli, they do not typically produce pyocyanin or exhibit the specific characteristics described in the question. C: Staphylococcus aureus - Staphylococcus aureus is a gram-positive cocci, not a gram-negative bacilli. It does not match the given description. D: Staphylococcus epidermidis - Staphylococcus epidermidis is also a gram-positive cocci, not a gram-negative bacilli. It does
Question 8 of 9
What is the role of bacterial plasmids?
Correct Answer: C
Rationale: The correct answer is C: Carry genes for antibiotic resistance. Bacterial plasmids are small, circular DNA molecules that can be transferred between bacteria, carrying genes such as antibiotic resistance. This allows bacteria to survive in the presence of antibiotics. Plasmids do not directly play a role in protein synthesis (choice A) or DNA replication (choice B). Plasmids are not responsible for motility (choice D) as that function is usually carried out by flagella or other cellular structures.
Question 9 of 9
The causative agent of botulism causes severe food poisoning. Specify the most characteristic morphological feature of botulism causative agent:
Correct Answer: D
Rationale: The correct answer is D: Thin mobile bacillus with central spore. This is because the causative agent of botulism, Clostridium botulinum, is a gram-positive bacillus that typically appears as a thin rod-shaped bacterium with a central endospore. This characteristic morphology is essential in the identification of Clostridium botulinum. A: Gram-positive bacillus with subterminal spore - This is incorrect as Clostridium botulinum typically has a central endospore, not a subterminal one. B: Thick gram-positive non-spore-forming bacillus - This is incorrect as Clostridium botulinum forms endospores, although they are not thick. C: Gram-positive bacillus with terminal spore - This is incorrect as the spore of Clostridium botulinum is typically central, not terminal.