Question 1

Which of the following best describes the structure of a mold's cell wall?

Accepted Answer

It is composed mainly of chitin and glucans.

Question 2

A laboratory technician observes a fuzzy, filamentous colony growing on a petri dish. Under the microscope, she sees long, branching structures. What are these structures called?

Accepted Answer

Hyphae

Question 3

Which of the following statements correctly distinguishes between vegetative mycelium and aerial mycelium?

Accepted Answer

Vegetative mycelium absorbs nutrients from the substrate, while aerial mycelium projects above the surface and is involved in spore production.

Question 4

Which of the following is the correct sequence for asexual reproduction in molds?

Accepted Answer

Hyphae → Aerial mycelium → Spore formation (conidia or sporangiospores) → Germination

Question 5

A patient presents with a persistent cough and chest pain. A sputum sample reveals septate hyphae with conidial heads under the microscope. Which mold is most likely responsible for this infection?

Accepted Answer

Aspergillus

Question 6

Which of the following best describes conidia?

Accepted Answer

Asexual, non-motile spores formed at the tips or sides of hyphae

Question 7

Which of the following molds is known for producing sporangiospores?

Accepted Answer

Rhizopus

Question 8

A laboratory is attempting to culture fungi from a skin scraping. Which medium should be used to best support fungal growth and inhibit bacterial contamination?

Accepted Answer

Sabouraud dextrose agar

Question 9

Which of the following structures is found on Aspergillus hyphae and is responsible for producing conidia?

Accepted Answer

Phialide

Question 10

A child presents with a circular, red, scaly lesion on the scalp. Microscopic examination of a skin scraping reveals septate hyphae and numerous macroconidia. What is the most likely diagnosis?

Accepted Answer

Ringworm (tinea capitis)

Question 11

Which of the following best describes dermatophytes?

Accepted Answer

Fungi that infect keratinized tissues such as skin, hair, and nails

Question 12

A laboratory technician is using Dermatophyte Test Medium (DTM) to culture a suspected dermatophyte. What color change indicates a positive result, and what is the underlying reason?

Accepted Answer

The medium turns red due to alkaline byproducts from protein metabolism.

Question 13

Which of the following is a common misconception about the classification of molds?

Accepted Answer

All molds produce conidia as their only reproductive structure.

Question 14

Which of the following is true regarding macroconidia and microconidia?

Accepted Answer

Macroconidia are larger, multicellular spores, while microconidia are smaller and usually unicellular.

Question 15

A patient with uncontrolled diabetes develops a rapidly progressing sinus infection. Microscopic examination reveals broad, non-septate hyphae with sporangia. Which mold is most likely responsible?

Accepted Answer

Rhizopus

Question 16

Which of the following best describes the function of conidiophores?

Accepted Answer

They are specialized hyphae that bear conidia.

Question 17

Which of the following equations best represents the pH change in DTM medium after dermatophyte growth, assuming initial pH is $$pH_0$$ and final pH is $$pH_f$$?

Accepted Answer

$$pH_f = pH_0$ + \Delta pH$$ where $$\Delta pH \u003e 0$$

Question 18

Which of the following is a key feature used to identify Penicillium under the microscope?

Accepted Answer

Brush-like arrangement of conidiophores with chains of conidia

Question 19

A skin scraping is placed on a slide with potassium hydroxide (KOH) and examined under the microscope. What is the primary purpose of using KOH in this diagnostic procedure?

Accepted Answer

To dissolve keratin and cellular debris, making fungal elements more visible

Question 20

Which of the following best explains why dermatophytes are able to grow on DTM medium?

Accepted Answer

They utilize keratin as a nutrient source, producing alkaline byproducts that change the medium's color.

Microbiology Study Guide: Molds, Fungi, and Their Identification

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