Microbiology Mcqs

Q:

Which of the following animallike flagellates has a flagellum originating from the midportion of the cell?

A) amastigote B) promastigote
C) epimastigote D) trypomastigote
 
Answer & Explanation Answer: C) epimastigote

Explanation: The epimastigote has a flagellum originating from the midportion of the cell. It is a morphological stage of Leishmania and Trypanosoma.

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Q:

Which drug is used for the treatment of leishmaniasis?

A) chloroquine phosphate B) metronidazole
C) suramin D) sodium stibogluconate
 
Answer & Explanation Answer: D) sodium stibogluconate

Explanation: Leishmaniasis can be treated with the drug sodium stibogluconate. This drug is used for the treatment of protozoan diseases.

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23
Q:

The antibiotic griseofulvin is active against deep mycoses.

A) True B) False
 
Answer & Explanation Answer: B) False

Explanation: The antibiotic griseofulvin is active against the dermatophyte infections (superficial skin infections) but not against the deep mycoses (systemic diseases caused by fungi).

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21
Q:

Miconazole is active against which of the following fungal infections?

A) coccidioidomycosis B) cryptococcosis
C) moniliasis D) sporotrichosis
 
Answer & Explanation Answer: A) coccidioidomycosis

Explanation: Miconazole is very active against coccidioidomycosis and paracoccidioidomycosis. It reacts with cytoplasmic membranes and causes them to leak.

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26
Q:

Which of the following antibiotics causes inhibition of ergosterol biosynthesis?

A) amphotericin B B) 5-fluorocytosine
C) ketoconazole D) miconazole
 
Answer & Explanation Answer: C) ketoconazole

Explanation: The mechanism of action for ketoconazole is inhibition of ergosterol biosynthesis, an important step in the synthesis of fungal cell walls and membranes.

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23
Q:

5-fluorocytosine is which type of antibiotic?

A) polyene B) pyrimidine antimetabolites
C) imidazole D) antibacterial
 
Answer & Explanation Answer: B) pyrimidine antimetabolites

Explanation: 5-fluorocytosine is a type of pyrimidine antimetabolite which is especially effective in the treatment of yeast infections.

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22
Q:

Polyene antibiotics act on the plasma membrane of the fungus.

A) True B) False
 
Answer & Explanation Answer: A) True

Explanation: Polyene antibiotics like the nystatin and amphotericin B act on the plasma membrane of the fungus, combining with membrane sterols, and cause leakage of intracellular potassium and other metabolites.

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60
Q:

Nystatin is effective in curing ____________

A) Deep mycoses B) Dermatophyte infections
C) Systemic mycoses D) Candida infections
 
Answer & Explanation Answer: D) Candida infections

Explanation: Nystatin is effective in topical Candida infections but not in deep mycoses or even dermatophyte infections.

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