MYCOLOGY MCQs — Complete Bank – 47 MCQs | Kenya MBChB

47 Year 3: Medical Mycology exam questions on MYCOLOGY MCQs — Complete Bank for medical students. Includes MCQs, answers, explanations and written questions. Sa

This MCQ set contains 47 questions on MYCOLOGY MCQs — Complete Bank in the Year 3: Medical Mycology unit. Each question includes the correct answer and a detailed explanation for active recall and exam preparation.

Q1: An organism without a known sexual stage of reproduction would be classified in which of the following fungal groups?

  1. A. Zygomycota
  2. B. Mitosporic fungi
  3. C. Ascomycota
  4. D. Basidiomycota
  5. E. Chytridiomycota

Correct answer: B – Mitosporic fungi

Fungi with no known sexual stage are classified as Fungi Imperfecti (Deuteromycota/Mitosporic fungi). They reproduce exclusively through asexual means via mitosis, producing conidia. Examples include Candida and Aspergillus species in their imperfect forms.

Q2: An antifungal drug such as Miconazole inhibits proper formation of which cellular component?

  1. A. Cell wall formation
  2. B. Plasma membrane formation
  3. C. DNA synthesis
  4. D. Microtubule formation
  5. E. Protein synthesis

Correct answer: B – Plasma membrane formation

Miconazole is an azole antifungal that inhibits the enzyme lanosterol 14-α-demethylase, blocking ergosterol biosynthesis and disrupting the fungal plasma membrane.

Q3: Which of the following fungi would you most likely find growing in pigeon droppings?

  1. A. Trichophyton
  2. B. Pneumocystis
  3. C. Cryptococcus
  4. D. Coccidioides
  5. E. Sporothrix

Correct answer: C – Cryptococcus

Cryptococcus neoformans thrives in soil enriched by pigeon and bird droppings. The nitrogen-rich guano provides ideal growth conditions.

Q4: Which fungal condition causes more than 200 million cases per year worldwide, with symptoms including an itching sensation and burning internal pain?

  1. A. Onychomycosis
  2. B. Thrush
  3. C. Tinea cruris (Jock itch)
  4. D. Vulvovaginitis
  5. E. Sporotrichosis

Correct answer: D – Vulvovaginitis

Vulvovaginal candidiasis caused by Candida albicans is among the most common fungal infections globally. Symptoms include vaginal itching, burning, and discharge.

Q5: The formation of arthrospores and spherules in infected tissue is characteristic of which fungal disease?

  1. A. Coccidioidomycosis
  2. B. Histoplasmosis
  3. C. Candidiasis
  4. D. Aspergillosis
  5. E. Blastomycosis

Correct answer: A – Coccidioidomycosis

Coccidioides immitis uniquely produces arthrospores in soil and spherules filled with endospores in tissue. This dimorphic characteristic is pathognomonic for Coccidioidomycosis (Valley Fever).

Q6: Aflatoxin is produced by which organism, and what type of substance is it?

  1. A. Sporothrix schenkii — Hallucinogen
  2. B. Aspergillus flavus — Carcinogen
  3. C. Claviceps purpurea — Hallucinogen
  4. D. Aspergillus niger — Mycotoxin
  5. E. Aspergillus fumigatus — Carcinogen

Correct answer: B – Aspergillus flavus — Carcinogen

Aflatoxin is produced by Aspergillus flavus and A. parasiticus . It is a potent hepatocarcinogen that contaminates food.

Q7: A girl who pricked her finger while pruning rose bushes develops a local pustule that progresses to an ulcer. Several nodules then develop along the local lymphatic drainage. What is the most likely causative agent?

  1. A. Aspergillus fumigatus
  2. B. Sporothrix schenckii
  3. C. Cryptococcus neoformans
  4. D. Candida albicans
  5. E. Coccidioides immitis

Correct answer: B – Sporothrix schenckii

This is the classic presentation of Sporotrichosis ('Rose Gardener's Disease'), caused by Sporothrix schenckii , which spreads in a characteristic lymphocutaneous pattern.

Q8: Fungal cells that reproduce by budding are seen in the infected tissues of patients with which of the following combinations?

  1. A. Candidiasis, cryptococcosis, and sporotrichosis
  2. B. Mycetoma, candidiasis, and mucormycosis
  3. C. Tinea corporis, tinea unguium, and tinea versicolor
  4. D. Sporotrichosis, mycetoma, and aspergillosis
  5. E. Histoplasmosis, candidiasis, and sporotrichosis

Correct answer: A – Candidiasis, cryptococcosis, and sporotrichosis

All three pathogens ( Candida , Cryptococcus , Sporothrix ) exist as budding yeast forms in host tissue at 37°C.

Q9: Which of the following statements regarding paracoccidioidomycosis is NOT correct?

  1. A. The etiologic agent is a dimorphic fungus
  2. B. Most patients acquired their infections in South America
  3. C. Many patients develop cutaneous and mucocutaneous lesions
  4. D. The vast majority of patients with active disease are males
  5. E. The etiologic agent is inherently resistant to amphotericin B

Correct answer: E – The etiologic agent is inherently resistant to amphotericin B

Paracoccidioides brasiliensis is not inherently resistant to amphotericin B; it is an effective treatment for severe cases. The other statements are correct.

Q10: A kidney transplant patient develops nosocomial systemic candidiasis. The isolated Candida glabrata strain is resistant to fluconazole. What is the most reasonable oral alternative?

  1. A. Flucytosine
  2. B. Posaconazole
  3. C. Griseofulvin
  4. D. Amphotericin B
  5. E. Clotrimazole

Correct answer: B – Posaconazole

Candida glabrata is notorious for azole resistance. Posaconazole is a broad-spectrum extended triazole effective against fluconazole-resistant strains and is available orally.

Q11: All of the following are characteristics of systemic mycoses (deep mycoses) EXCEPT:

  1. A. Most of the dimorphic fungi cause the infection
  2. B. Pathogenesis mostly occurs due to the inhalation of spores
  3. C. The most common body part is the lungs for ALL fungal infections
  4. D. Aspergillosis and mucormycosis are systemic mycoses
  5. E. Infection can develop in patients who are immunocompetent

Correct answer: C – The most common body part is the lungs for ALL fungal infections

The lungs are not the site for ALL fungal infections; some, like sporotrichosis and mycetoma, enter through the skin.

Q12: Thousands of people in the western USA suddenly developed flu-like symptoms and pneumonia in 1992. The causative agent was found to be fungal spores in soil and air, causing fever, cough, and fatigue. The disease was termed Valley Fever. What is the pathogen?

  1. A. Aspergillus niger
  2. B. Paracoccidioides brasiliensis
  3. C. Blastomyces dermatitidis
  4. D. Coccidioides immitis
  5. E. Tinea nigra

Correct answer: D – Coccidioides immitis

Valley Fever is caused by Coccidioides immitis , endemic to the southwestern USA, where inhaled arthrospores from soil cause acute pulmonary infection.

Q13: Which pathogen isolated from a sputum specimen shows mold growth with tuberculate macroconidia and oval microconidia in laboratory culture?

  1. A. Histoplasma capsulatum
  2. B. Coccidioides immitis
  3. C. Blastomyces dermatitidis
  4. D. Paracoccidioides brasiliensis
  5. E. Penicillium notatum

Correct answer: A – Histoplasma capsulatum

The mold phase of Histoplasma capsulatum is characterized by large tuberculate macroconidia and smaller oval microconidia.

Q14: The fungi Trichosporon commonly causes superficial infection of hair called white piedra. Which species of Trichosporon specifically causes scalp hair white piedra?

  1. A. Trichosporon ovoides
  2. B. Trichosporon inkin
  3. C. Trichosporon asahii
  4. D. None of the above

Correct answer: A – Trichosporon ovoides

Trichosporon ovoides is the species that specifically causes white piedra on scalp hair.

Q15: A 26-year-old man develops itchy, white flaky, and stinging patches between the toe webs and soles of the feet. The infection is characterized by inflammation and skin fissures. Which is the most likely etiological agent?

  1. A. Trichophyton tonsurans
  2. B. Microsporum canis
  3. C. Trichophyton equinum
  4. D. Trichophyton rubrum
  5. E. Microsporium gypseum

Correct answer: D – Trichophyton rubrum

This describes Tinea pedis (Athlete's Foot), with Trichophyton rubrum being the most common cause worldwide, characterized by chronic interdigital infections.

Q16: Which of the following best describes the lesion characteristics of Pityriasis Versicolor?

  1. A. Hypopigmented and hyperpigmented round and smooth macules on the skin
  2. B. Hypopigmented and hyperpigmented irregular macules on the skin
  3. C. Yellow pigmented patches around fingernails
  4. D. White pigmented patches around the neck and face

Correct answer: B – Hypopigmented and hyperpigmented irregular macules on the skin

Pityriasis Versicolor presents as irregular hypo and hyperpigmented macules, predominantly on the trunk, chest, and upper arms, caused by Malassezia furfur .

Q17: A 2-year-old girl develops a rash with raised borders on her face and arms. The source of infection is found to be the pet cat, which has the same type of rash on its skin. Which fungi is the most likely common cause?

  1. A. Trichophyton rubrum
  2. B. Trichophyton tonsurans
  3. C. Microsporum canis
  4. D. Candida albicans
  5. E. Microsporon audouinii

Correct answer: C – Microsporum canis

Microsporum canis is a zoophilic dermatophyte commonly transmitted from cats and dogs to humans, causing tinea corporis (ringworm).

Q18: Which of the following is the most correct statement regarding Deuteromycetes, also known as Fungi Imperfecti?

  1. A. They are the causative agents of subcutaneous mycoses
  2. B. The sexual reproduction method is not clearly known
  3. C. They produce basidiospores through asexual reproduction
  4. D. None of the above

Correct answer: B – The sexual reproduction method is not clearly known

Deuteromycetes are characterized by the absence or unknown nature of their sexual (perfect) reproductive stage. They reproduce asexually via conidia.

Q19: Which of the following statements about fungi is NOT true?

  1. A. Some fungi are photosynthetic
  2. B. Fungi have cell walls made of chitin
  3. C. Fungi are heterotrophic organisms
  4. D. Some fungi are unicellular
  5. E. Fungi consist of yeasts and molds

Correct answer: A – Some fungi are photosynthetic

Fungi are strictly heterotrophic and cannot photosynthesize; they obtain nutrients by absorption.

Q20: Most dimorphic pathogens exist in which forms at which temperatures?

  1. A. Asexual at 23°C and sexual at 37°C
  2. B. Sexual at 23°C and asexual at 37°C
  3. C. Filamentous at 37°C and yeast forms at 23°C
  4. D. Yeasts at 10°C and molds at 23°C
  5. E. Filamentous at 23°C and yeast forms at 37°C

Correct answer: E – Filamentous at 23°C and yeast forms at 37°C

Dimorphic fungi typically grow as filamentous molds at environmental temperatures (around 23-25°C) and as yeast forms at human body temperature (37°C).

Q21: A fungal mycelium may contain which of the following?

  1. A. Septate hyphae
  2. B. A coenocytic cytoplasm
  3. C. Chitinous cell walls
  4. D. Mitochondria
  5. E. All of the above

Correct answer: E – All of the above

A fungal mycelium can exhibit septate or coenocytic hyphae, always has chitin in its cell walls, and being eukaryotic, contains mitochondria.

Q22: All of the following are examples of asexual spore formation EXCEPT:

  1. A. Arthrospores
  2. B. Conidia
  3. C. Sporangiospores
  4. D. Basidiospores
  5. E. Yeast

Correct answer: D – Basidiospores

Basidiospores are sexual spores, produced through meiosis in Basidiomycota. Arthrospores, conidia, and sporangiospores are all forms of asexual reproduction. Yeast reproduction is typically asexual budding.

Q23: Which of the following is a correct statement about the mechanisms of action of antifungal drugs?

  1. A. Polyenes disrupt the fungal cell wall.
  2. B. Azoles inhibit ergosterol synthesis.
  3. C. Allylamines inhibit chitin synthesis.
  4. D. Echinocandins inhibit ergosterol synthesis.
  5. E. Flucytosine targets cell wall glucans.

Correct answer: B – Azoles inhibit ergosterol synthesis.

Azoles inhibit the enzyme lanosterol 14-α-demethylase, a key step in ergosterol biosynthesis. Polyenes bind ergosterol. Allylamines also inhibit ergosterol synthesis. Echinocandins inhibit glucan synthesis.

Q24: A physician visiting a rural Latin American village finds that many mature males but few immature males or females of any age are afflicted by a particular fungal disease. What is the likely diagnosis?

  1. A. Mycetoma
  2. B. Blastomycosis
  3. C. Paracoccidioidomycosis
  4. D. Mucormycosis
  5. E. Histoplasmosis

Correct answer: C – Paracoccidioidomycosis

Paracoccidioidomycosis has a striking male predominance, thought to be due to estrogen's protective effect, and is endemic to Latin America.

Q25: Which fungus has the ability to attack and invade hair?

  1. A. Trichophyton
  2. B. Rhizopus
  3. C. Microsporum
  4. D. Sporothrix
  5. E. Epidermophyton

Correct answer: A – Trichophyton

Both Trichophyton and Microsporum can invade hair. Epidermophyton infects only skin and nails. Rhizopus and Sporothrix are not dermatophytes.

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