microbiology chapter 14 test bank -Nurselytic

Correct Answer: C

Rationale: The correct answer is C: Nucleic acid and proteins. Viruses contain genetic material in the form of nucleic acids (DNA or RN
A) surrounded by a protein coat. This genetic material carries instructions for viral replication. Proteins are also essential components of viruses, serving various functions like facilitating viral entry into host cells. Option A is incorrect as lipids are not main components of viruses. Option B is incorrect as lipids are not typically found in the main structure of viruses. Option D is incorrect as lipids are not primary components of viruses, and glycoproteins are not always present in the main structure of viruses.

Correct Answer: A

Rationale:
Step-by-step rationale for why choice A is correct:
1. Helicobacter pylori, the bacteria causing helicobacteriosis, is microaerophilic, requiring low oxygen levels.
2. Cultivation conditions must mimic the natural environment of the bacteria.
3. Failure to provide a microaerophilic environment can hinder bacterial growth.
4. Thus, the ability to cultivate these bacteria requires consideration of their microaerophilic nature.

Summary:
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Choice A is correct because Helicobacter pylori is a microaerophilic bacteria.
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Choice B (Presence of urease) is incorrect as it is a characteristic used for diagnosis, not cultivation.
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Choice C (Absence of spores and capsules) is incorrect as it does not relate to cultivation requirements.
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Choice D (Colonization of gastral cells) is incorrect as it pertains to bacterial behavior, not cultivation needs.

Correct Answer: A

Rationale: The correct answer is A: Lamblia. The description matches the characteristics of Giardia lamblia - a protozoan parasite that causes giardiasis. The piriform bodies, 4 pairs of filaments, and two symmetrically located nuclei are specific to Giardia lamblia. It is important to differentiate it from the other choices. Dysentery ameba (choice
B) typically has a single nucleus and lacks the specific characteristics described. Trichomonas (choice
C) is a flagellated protozoan with different morphology and does not match the given description. Intestinal ameba (choice
D) such as Entamoeba histolytica usually has a single nucleus and different body shape compared to the described organism.

Correct Answer: B

Rationale: The correct answer is B: Bordetella pertussis. This bacterium causes whooping cough by infecting the respiratory tract. It produces toxins that lead to severe coughing fits characteristic of the disease. Clostridium botulinum (
A) causes botulism, Streptococcus pneumoniae (
C) causes pneumonia, and Neisseria meningitidis (
D) causes meningitis, not whooping cough. B. pertussis is the only bacterium specifically associated with whooping cough.

Correct Answer: A

Rationale: The correct answer is A: Gram-positive rod-shaped bacterium. Campylobacter fetus is actually a Gram-negative bacterium. This is because it has a thin peptidoglycan layer in its cell wall, which does not retain the crystal violet stain used in the Gram-staining technique. It appears red or pink under a microscope after counterstaining with safranin.
Therefore, statement A is incorrect.
B: Optimal temperature for cultivation 35-37C - Correct, as Campylobacter fetus thrives at this temperature range.
C: Opportunistic pathogen causes infections usually in newborns, immunocompromised patients, and cancer - Correct, as Campylobacter fetus can cause infections in these populations.
D: Fastidious, microaerophile - Correct, as Campylobacter fetus is fastidious and requires specific growth conditions, including low oxygen levels.