Question 1

Which of the following statements best explains why fungi are generally insensitive to antibiotics such as penicillin?

Accepted Answer

Fungi have a cell wall made of chitin, not peptidoglycan, so penicillin is ineffective.

Question 2

A patient presents with a white, powdery coating on their tongue. Laboratory analysis identifies the causative agent as Candida albicans. Which medication and mechanism of action would be most appropriate for treatment?

Accepted Answer

Nystatin; binds to ergosterol, forming pores in the fungal membrane.

Question 3

Which of the following best describes the process of plasmogamy in the fungal sexual life cycle?

Accepted Answer

Fusion of cytoplasm from two compatible haploid cells, resulting in a dikaryotic cell.

Question 4

Which feature distinguishes yeasts from molds?

Accepted Answer

Yeasts reproduce by budding; molds grow as multicellular hyphae.

Question 5

A dimorphic fungus is cultured at 37°C and 25°C. What forms would you expect to see at each temperature?

Accepted Answer

Yeastlike at 37°C; moldlike at 25°C.

Question 6

Which of the following is a correct pairing of fungal phylum and its characteristic spore type?

Accepted Answer

Ascomycota – ascospore

Question 7

A patient with HIV develops cryptococcal meningitis. Which drug is used in the induction phase of treatment, and what is its mechanism?

Accepted Answer

Amphotericin B; disrupts fungal cell membrane by binding ergosterol.

Question 8

Which of the following best describes the metabolic capabilities of fungi compared to bacteria?

Accepted Answer

Fungi are limited to heterotrophic metabolism; bacteria can be heterotrophic or autotrophic.

Question 9

Which type of mycosis is most likely to affect hair, skin, and nails?

Accepted Answer

Cutaneous mycosis

Question 10

Which of the following statements about protozoan cysts is correct?

Accepted Answer

Cysts allow protozoa to survive harsh environmental conditions and facilitate transmission between hosts.

Question 11

A patient presents with gastrointestinal symptoms after drinking untreated water while camping. Microscopy reveals a flagellated protozoan with two nuclei and no mitochondria. What is the most likely diagnosis?

Accepted Answer

Giardiasis caused by Giardia intestinalis

Question 12

Which of the following best describes the life cycle of Plasmodium falciparum in humans?

Accepted Answer

Sporozoites undergo schizogony in the liver, producing merozoites that infect red blood cells.

Question 13

Which of the following is a distinguishing feature of cestodes (tapeworms) compared to trematodes (flukes)?

Accepted Answer

Cestodes have a scolex with suckers and absorb nutrients through their cuticle.

Question 14

Which of the following best explains why parasitic helminths often have a reduced nervous system compared to their free-living relatives?

Accepted Answer

The host environment is relatively constant, so extensive sensory and nervous systems are unnecessary.

Question 15

A child presents with perianal itching, especially at night. Microscopic examination of tape applied to the perianal region reveals oval eggs. What is the most likely causative agent and treatment?

Accepted Answer

Enterobius vermicularis (pinworm); treated with albendazole.

Question 16

Which of the following best describes the mechanism of action of albendazole in treating nematode infections?

Accepted Answer

Prevents glucose absorption, depleting the worm's energy stores.

Question 17

Which of the following is true regarding the sexual reproduction of protozoa?

Accepted Answer

It is called conjugation and involves the exchange of genetic material between two cells.

Question 18

Which of the following is a correct statement about the ergosterol in fungal cell membranes?

Accepted Answer

Ergosterol is unique to fungi and is targeted by many antifungal drugs.

Question 19

Which of the following best describes the role of intermediate and definitive hosts in the life cycle of parasitic helminths?

Accepted Answer

Intermediate hosts support larval development; definitive hosts support adult, sexually mature stages.

The Eukaryotes of Microbiology: Fungi, Protozoa, and Helminths

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