Mycology: Study of Fungi

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What characteristic differentiates yeast from molds?

Yeasts are multicellular while molds are unicellular.

Yeasts reproduce by spores while molds reproduce by budding.

Yeasts are unicellular while molds are multicellular. (correct)

Yeasts have chitin in their cell walls while molds do not.

Which substance is a major component of the cell wall in fungi?

Chitin (correct)

Cellulose

Peptidoglycan

Lignin

Candida albicans exhibits which of the following characteristics?

It is a unicellular fungus that does not bud.

It has pseudohyphae and is gram positive. (correct)

It is a true mold.

It reproduces exclusively by spore formation.

Fungi can be classified based on their morphology. Which of the following is NOT a classification of fungi?

Bacteria Signup and view all the answers

Which of the following fungi primarily reproduce via budding?

Candida albicans Signup and view all the answers

How do most fungi obtain their nutrients?

By consuming dead and decaying matter. Signup and view all the answers

What are the two main types of fungi based on their cellular organization?

Unicellular and multicellular Signup and view all the answers

Which of the following statements about fungal infections is true?

Nosocomial infections and opportunistic infections are common in immunocompromised individuals. Signup and view all the answers

What distinguishes septate hyphae from aseptate hyphae?

Septate hyphae are divided by septa. Signup and view all the answers

Which of the following fungi exhibits dimorphism?

Penicillium marneffei Signup and view all the answers

What is the primary method of reproduction for filamentous fungi?

Fragmentation of hyphae Signup and view all the answers

What type of spores are formed within a sac during asexual reproduction?

Sporangiospores Signup and view all the answers

Which of the following describes a characteristic of the Deuteromycota classification?

It is a catch-all category for unclassified fungi Signup and view all the answers

At which temperature does the yeast form typically develop in dimorphic fungi?

37°C Signup and view all the answers

Which of the following is a characteristic feature of conidiospores?

They are unicellular or multicellular and not enclosed in a sac. Signup and view all the answers

Which fungus is known for causing opportunistic infections in AIDS patients?

Candida albicans Signup and view all the answers

Study Notes

Mycology: Study of Fungi

Mycology is the study of fungi, including yeasts and molds.
Yeasts are unicellular, rounded fungi.
Molds are multicellular, filamentous fungi.
Fungi reproduce via budding (yeasts) or spores (molds).
Fungi have rigid cell walls containing chitin, glucan, mannans.
Cell membranes contain ergosterol.
Fungi are eukaryotic organisms with a nucleus, nuclear membrane, endoplasmic reticulum, and mitochondria.

Characteristics of Fungi

Fungi are important as plant, human, and animal pathogens.
Over 70% of plant diseases are fungal.
Many fungi are saprophytes (consuming dead matter).
Other fungi are parasites.
Most fungi are multicellular, but yeasts are unicellular.
Fungi are aerobes or facultative anaerobes.
Cell walls are primarily composed of chitin.
Many human fungal infections are nosocomial (hospital-acquired) or occur in immunocompromised individuals (opportunistic infections).

Morphological Classification of Medically Important Fungi

Yeasts: Unicellular, non-filamentous, oval/spherical cells. Reproduce by budding.
- Example: Candida albicans (yeast-like), Cryptococcus neoformans (true yeast, capsulated).
Yeast-like fungi: Grow partly as yeast cells and partly as elongated cells resembling hyphae (pseudohyphae). Reproduce by budding.
- Example: Candida albicans
Molds/Filamentous fungi: Multicellular, filamentous. Form a mycelium composed of hyphae. Reproduce via spore formation.
- Identified by appearance, colony characteristics, and spore types.
- Examples: Aspergillus, Penicillium, dermatophytes.
- Hyphae can be septate (divided by cross-walls) or aseptate (uninterrupted).
- Mycelium is the visible filamentous mass.
- Penicillium: Brush-like arrangement of conidia, initially velvety/white, later powdery/blue-green.
- Aspergillus: Green-colored colonies on SDA/PFA, conidiophores, sterigmata, conidia visible with Lactophenol Cotton Blue stain.
Dimorphic fungi: Can exist as both molds and yeasts, depending on growth conditions.
- Mold form produces hyphae; yeast form reproduces by budding.
- Primarily infect the lungs.
- Dimorphism often temperature-dependent (e.g., yeast at 37°C and mold at 25°C).
- Examples: Blastomyces dermatitidis, Coccidioides immitis, Histoplasma capsulatum, Sporothrix schenckii, Penicillium marneffei, Paracoccidioides brasiliensis.

Reproduction and Life Cycle of Fungi

Yeasts and yeast-like fungi reproduce by budding.
Filamentous fungi reproduce asexually (fragmentation of hyphae).
Spores are for both sexual and asexual reproduction.
Asexual spores (e.g., conidiospores, chlamydospores, sporangiospores) are produced by aerial hyphae.
Sexual spores are produced by fusion of nuclei from opposite mating strains.

Divisions of Fungi (Systematic Classification)

Deuteromycota (Fungi Imperfecti): Unknown to produce sexual spores. Reproduce asexually.
- Example: Candida albicans (vaginal yeast infections; opportunistic in AIDS), Malassezia furfur, Sporothrix schenckii.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the fascinating world of mycology, focusing on the characteristics, classifications, and importance of fungi. Learn about yeasts, molds, and their various roles as pathogens, saprophytes, and members of ecosystems. This quiz will deepen your understanding of fungal biology and its medical significance.