Chapter 5 part II Fungi Flashcards
What are some examples of fungi used as food?
Mushrooms and truffles
Fungi significance: Antibiotics
Examples: Penicillin, Cephalosporin, Cyclosporine, Mevinic acids.
Mycology. How many species?
The study of fungi. Over 100,000 species, 200 pathogenic to humans.
Mycoses
Diseases caused by fungi.
Fungi nutrient acquisition facts
Nonphotosynthetic, chemoheterotrophs; absorb nutrients via secreted enzymes.
What are saprobes?
Fungi that absorb nutrients from dead organisms.
Fungal growth pH preference
Grow best at pH 5, which is too acidic for most bacteria.
Molds vs. Yeasts
Molds: filamentous hyphae
Yeasts: unicellular, globular.
Dimorphic fungi
Can switch between yeast and mold forms based on environmental conditions.
Fungal cell walls
Composed of chitin and glucan; chitin is nitrogenous and flexible.
Hyphae
Long filaments forming the body of molds; can be septate or coenocytic.
Mycelium
Network of hyphae; aids in absorptive nutrition.
Aerial hyphae
Hyphae that extend above the surface; produce spore structures.
Mycorrhizae
Symbiotic associations with plant roots; help plants obtain phosphorus/nitrogen.
Fungal asexual reproduction
Via hyphal growth, asexual production of spores (mitosis), or simple cell division: budding (yeasts).
Fungal sexual reproduction; produce what?
Involves plasmogamy, karyogamy, meiosis; produces resistant spores.
Mucoromycota
Phylum includes Rhizopus stolonifer (black bread mold); causes mucormycosis.
Mucormycosis
Opportunistic infections in immunocompromised individuals (respiratory/sinus).
Sporangium
Fungal cell that holds spores.
Sporangiophore
Entire spore-bearing structure in Mucoromycota.
Mucoromycete asexual reproduction
Via sporangiospores formed in sporangia.
Mucoromycete sexual reproduction
Involves plasmogamy (zygosporangium), karyogamy, meiosis.
Ascomycota
Diverse phylum: molds (Aspergillus), yeasts (Saccharomyces), mushrooms.
Aspergillus
Pathogenic mold; produces aflatoxin (carcinogenic).
Conidiophore
Hyphal structure producing asexual conidia (e.g., in Aspergillus).
Conidia
Asexual spores formed on conidiophores.
Ascus
Sac-like structure in Ascomycota containing ascospores (sexual spores) formed at the end of diploid growth. Where karyogamy occurs.
Ascospore
Haploid spores produced via meiosis in asci.
Saccharomyces cerevisiae
Baker’s yeast; used in bread/alcohol production; dimorphic.
Candida albicans
Pathogenic yeast; causes vaginal/skin infections.
Yeast budding
Asexual reproduction: daughter cell grows from mother cell.
Pseudohyphae
Chains of elongated yeast cells resembling hyphae; 1 of 2 results of budding yeasts (other option is globular cell)
Chitin
Strong, flexible nitrogenous polysaccharide in fungal cell walls; also in insect exoskeletons.
Glucan
Polysaccharide containing sugars in fungal cell walls (not in mammalian cells); maintains osmotic stability.
β-glucans
Type of glucan; important for fungal cell wall integrity.
Fungal decomposers
Recycle organic waste via absorptive nutrition.
Opportunistic fungi and ex.s
Cause disease in immunocompromised hosts (e.g., Aspergillus, Candida).
Aflatoxin
Toxin by Aspergillus; damages DNA, causes liver cancer.
Zygosporangium
Structure formed by fusion of mating types in Mucoromycota.
Plasmogamy
Fusion of cytoplasm from two mating types; precedes karyogamy.
Karyogamy
Fusion of nuclei to form a diploid zygote.
Dikaryotic hyphae
Hyphae with two genetically distinct nuclei (in Ascomycota).
Ascocarp
Fruiting body of Ascomycota where asci develop.
Sterigmata
Cells radiating from vesicles; produce spores in Aspergillus & penicillium; can be uniseriate or biseriate sterigmata
Uniseriate sterigmata
Single layer of spore-producing cells.
Biseriate sterigmata
Two layers (metula → phialide → spores).
Phialides
Cells that directly produce conidia in Aspergillus.
Metula
Secondary spore-producing cells in biseriate sterigmata.
Facultative anaerobes
Most yeasts; can grow with/without oxygen.
Obligate aerobes
Most molds; require oxygen.
Fungal spoilage
Tolerate salt/acid/sugar; spoil jams, pickles, fruits.
Mycotoxins and ex.
Harmful fungal metabolites (e.g., aflatoxin).
Immunosuppressant drugs
Cyclosporine: derived from fungi; prevents transplant rejection = makes transplants possible.
Citric acid production
Fungi used industrially (e.g., soft drink industry).
Black bread mold
Rhizopus stolonifer; common in environment, rots organic matter.
Coenocytic hyphae
Hyphae without septa; multinucleated.
Septate hyphae
Hyphae divided by cross-walls (septa).
Fungal spores
Resistant to drying, heat, chemicals; aid dispersal.
Germlings
Early hyphal growth from germinated spores.
Vesicle (fungal)
Swollen structure supporting sterigmata in Aspergillus.
What are some products that fungi are used in manufacturing?
Bread, alcoholic beverages, soy sauce, some cheeses, citric acid
