Mycology: Trash men of the microbial world

Flashcards covering key concepts from the provided lecture notes on mycology, including fungal biology, life cycles, reproduction, nutrition, and disease classifications.

What is mycology?

The study of fungi.

How are fungi divided morphologically?

Filamentous (molds and mushrooms) and non-filamentous (yeasts).

Why are fungi increasingly important in medicine and agriculture?

They are involved in nosocomial infections and affect immunocompromised patients; they also form mycorrhizae for nutrient uptake and include crop pathogens.

What is mycorrhizae?

Symbiotic fungi associated with plant roots that aid nutrient uptake.

How do fungi differ from bacteria?

Fungi are eukaryotic, have sterols in their membranes, lack peptidoglycan, are heterotrophic, and have both sexual and asexual life cycles.

What is the major body of a mold called?

Thallus.

What are hyphae?

Long, thin filaments that compose the fungal body; they form a mycelium.

What are septate hyphae?

Hyphae with cross-walls called septa.

What are coenocytic hyphae?

Hyphae lacking septa, effectively a single cell with many nuclei.

What are vegetative vs aerial (reproductive) hyphae?

Vegetative hyphae absorb nutrients; aerial hyphae reproduce.

What is a mycelium?

A visible filamentous mass of hyphae.

What are yeasts?

Unicellular, nonfilamentous fungi that are spherical or oval; widely distributed.

What are the two main divisions of yeast growth?

Budding and fission.

Describe budding yeast.

A bud forms on the parent cell, the nucleus divides and moves into the bud, the bud grows and separates; bud scars mark division; up to about 24 daughter cells.

What is a pseudohypha?

Chains of budding cells that remain attached; Candida albicans uses pseudohyphae to invade tissue.

How do fission yeasts divide?

They elongate, replicate the nucleus and organelles, and pinch off to form two daughter cells; colonies can resemble bacteria.

Are yeasts aerobic or facultative?

Facultative anaerobes; they ferment sugars to CO2 and ethanol when oxygen is limited.

What is fungal dimorphism?

Some fungi can grow as yeasts or molds; in pathogens, this is often temperature-regulated (yeast at 37°C, mold at 25°C); CO2 can influence nonpathogenic forms.

How do filamentous fungi reproduce asexually?

By fragmentation of hyphae and spore formation.

What is the difference between fungal spores and bacterial spores?

Fungal spores are reproductive and can undergo genetic recombination; bacterial spores are not reproductive and mainly provide environmental resistance; fungal spores can increase organism numbers.

What are the two main types of asexual spores?

Conidiospores and sporangiospores.

What is an arthroconidium?

Single-celled spores formed by fragmentation of hyphae with thick walls (e.g., Coccidioides immitis).

What is a blastoconidium?

A bud forming off the parent cell (e.g., Cryptococcus).

What is a chlamydoconidium?

Thick-walled spores formed by rounding/enlarging of a hyphal segment (e.g., Candida albicans).

What is a sporangiospore?

A spore enclosed in a sporangium at the end of a sporangiophore.

What is a sporangium?

A sac enclosing spores at the end of a sporangiophore.

What are the three phases of sexual reproduction in fungi?

Plasmogamy, karyogamy, and meiosis.

What is a zygospore?

A zygospore forms within a zygosporangium after plasmogamy where nuclei fuse before meiosis.

What pH do fungi prefer for growth?

Approximately pH 5.0 (acidic).

What are the four classifications of mycoses?

Systemic, Subcutaneous, Cutaneous, and Opportunistic.