Q.1 Which of the following fungi is most commonly associated with superficial infections like athlete's foot?
Candida albicans
Aspergillus fumigatus
Trichophyton rubrum
Cryptococcus neoformans
Explanation - Trichophyton rubrum is a dermatophyte responsible for most cases of athlete's foot, jock itch, and nail infections.
Correct answer is: Trichophyton rubrum
Q.2 Candida albicans primarily causes infections in which body system?
Respiratory system
Gastrointestinal tract
Genitourinary tract
Central nervous system
Explanation - Candida albicans commonly causes infections such as thrush and vaginal yeast infections in the genitourinary tract.
Correct answer is: Genitourinary tract
Q.3 Which of the following fungi produces aflatoxins, a potent carcinogen?
Aspergillus flavus
Histoplasma capsulatum
Rhizopus stolonifer
Microsporum canis
Explanation - Aspergillus flavus produces aflatoxins, which are highly toxic and carcinogenic, often contaminating grains and nuts.
Correct answer is: Aspergillus flavus
Q.4 Which fungal structure is primarily responsible for sexual reproduction?
Hyphae
Spores
Conidia
Zygospores
Explanation - Zygospores are sexual spores formed during the sexual reproduction of certain fungi like Rhizopus species.
Correct answer is: Zygospores
Q.5 Histoplasma capsulatum is primarily transmitted through which route?
Skin contact
Inhalation of spores
Contaminated water
Insect bite
Explanation - Histoplasma capsulatum is a dimorphic fungus whose spores are inhaled, leading to pulmonary infections.
Correct answer is: Inhalation of spores
Q.6 Which of the following fungi is known to cause systemic infection in immunocompromised patients?
Aspergillus fumigatus
Penicillium notatum
Saccharomyces cerevisiae
Mucor indicus
Explanation - Aspergillus fumigatus is an opportunistic pathogen that can cause invasive aspergillosis in immunocompromised individuals.
Correct answer is: Aspergillus fumigatus
Q.7 Which laboratory test is used to detect fungal cell wall components like β-glucan?
ELISA
PCR
India ink staining
KOH mount
Explanation - ELISA can detect fungal antigens such as β-glucan, helping in the diagnosis of invasive fungal infections.
Correct answer is: ELISA
Q.8 Cryptococcus neoformans has a polysaccharide capsule that helps it evade the host immune system. This capsule can be visualized by which stain?
Gram stain
India ink stain
Periodic acid-Schiff stain
Giemsa stain
Explanation - India ink creates a negative stain highlighting the capsule of Cryptococcus neoformans under a microscope.
Correct answer is: India ink stain
Q.9 Which type of hyphae has cross-walls dividing the fungal filaments into cells?
Septate hyphae
Coenocytic hyphae
Pseudohyphae
Aerial hyphae
Explanation - Septate hyphae contain septa (cross-walls) separating individual cells within the hyphal filament.
Correct answer is: Septate hyphae
Q.10 Which fungus is most commonly associated with opportunistic infections in AIDS patients?
Aspergillus niger
Candida albicans
Trichophyton mentagrophytes
Penicillium chrysogenum
Explanation - Candida albicans frequently causes oral thrush, esophagitis, and systemic infections in immunocompromised individuals.
Correct answer is: Candida albicans
Q.11 Pneumocystis jirovecii primarily causes which type of infection?
Cutaneous infection
Pulmonary infection
Gastrointestinal infection
Urinary tract infection
Explanation - Pneumocystis jirovecii causes pneumonia, particularly in immunocompromised patients, previously known as Pneumocystis carinii.
Correct answer is: Pulmonary infection
Q.12 Which fungal group is characterized by the presence of zygospores during sexual reproduction?
Zygomycota
Ascomycota
Basidiomycota
Chytridiomycota
Explanation - Zygomycota produce zygospores as sexual spores, while asexual reproduction occurs via sporangiospores.
Correct answer is: Zygomycota
Q.13 Which of the following fungi is dimorphic, existing as mold in the environment and yeast in human tissues?
Histoplasma capsulatum
Aspergillus fumigatus
Rhizopus stolonifer
Microsporum gypseum
Explanation - Histoplasma capsulatum is a dimorphic fungus; it is mold at 25°C and yeast at 37°C.
Correct answer is: Histoplasma capsulatum
Q.14 Mucormycosis is most commonly caused by fungi in which genus?
Rhizopus
Candida
Aspergillus
Trichophyton
Explanation - Rhizopus species cause mucormycosis, an aggressive fungal infection often seen in diabetic or immunocompromised patients.
Correct answer is: Rhizopus
Q.15 Dermatophytes primarily digest which component of human tissue?
Collagen
Keratin
Elastin
Fibrin
Explanation - Dermatophytes metabolize keratin in hair, skin, and nails, causing superficial fungal infections.
Correct answer is: Keratin
Q.16 Which of the following is used for rapid microscopic detection of fungal elements in clinical specimens?
KOH mount
Blood culture
ELISA
PCR
Explanation - KOH dissolves human cells and debris, making fungal hyphae and spores visible under a microscope.
Correct answer is: KOH mount
Q.17 Which of the following fungi is known to form septate hyphae with conidial spores?
Aspergillus
Rhizopus
Candida
Mucor
Explanation - Aspergillus forms septate hyphae and produces asexual spores called conidia.
Correct answer is: Aspergillus
Q.18 Tinea corporis refers to fungal infection of which body part?
Scalp
Body skin
Feet
Nails
Explanation - Tinea corporis, also called ringworm, affects the smooth skin of the body excluding scalp, nails, and feet.
Correct answer is: Body skin
Q.19 Which antifungal drug inhibits ergosterol synthesis in fungal cell membranes?
Amphotericin B
Fluconazole
Griseofulvin
Caspofungin
Explanation - Fluconazole inhibits lanosterol 14-α-demethylase, blocking ergosterol synthesis essential for fungal membranes.
Correct answer is: Fluconazole
Q.20 Which of the following is a common opportunistic pathogen in hospital-acquired fungal infections?
Candida species
Trichophyton species
Microsporum species
Penicillium species
Explanation - Candida species, especially C. albicans, are major opportunistic pathogens causing nosocomial infections.
Correct answer is: Candida species
Q.21 Which stain is commonly used to identify fungi in tissue sections?
Gomori methenamine silver (GMS)
Hematoxylin and eosin
Gram stain
Wright stain
Explanation - GMS stains fungal cell walls black, providing excellent contrast for histopathological identification.
Correct answer is: Gomori methenamine silver (GMS)
Q.22 Which fungus is the primary cause of chromoblastomycosis?
Fonsecaea pedrosoi
Candida albicans
Aspergillus fumigatus
Trichophyton rubrum
Explanation - Fonsecaea pedrosoi is a dematiaceous fungus responsible for chronic subcutaneous infections like chromoblastomycosis.
Correct answer is: Fonsecaea pedrosoi
Q.23 Which of the following is a common method to identify fungi at the species level in the laboratory?
Culture morphology
Serological tests
PCR-based methods
All of the above
Explanation - Fungi can be identified using culture characteristics, serology, and molecular techniques like PCR for accurate species-level identification.
Correct answer is: All of the above
Q.24 Blastomyces dermatitidis is endemic to which regions?
Mississippi and Ohio river valleys
Sahara desert
Amazon rainforest
Himalayan region
Explanation - Blastomyces dermatitidis is endemic to North American river valleys, causing blastomycosis primarily in these areas.
Correct answer is: Mississippi and Ohio river valleys