Fungi Flashcards
A selection of learning objective answers pulled from the lecture slides, textbook, and user Ayla Kennedy's MMG 2010 Lecture Exam 2 to be customized to the fall 2024 version of the course
Describe the general structure and function of the nucleus
Holds genetic material
Describe the general structure and function of mitochondria
Powerhouse of the cell
Describe the general structure and function of a chloroplast
Holds chlorophyll; does photosynthesis
Describe the general structure and function of a ribosome
Synthesizes proteins
Describe the general structure and function of the endoplasmic reticulum
Lots of layers; rough ER synthesizes proteins and smooth ER synthesizes lipids
Describe the general structure and function of the golgi apparatus
Vesicle that packages things
Describe the general structure and function of a lysosome
Digests waste
Describe the general structure and function of the cytoskeleton
structure that helps the cell maintain its shape and internal organization
Define fungi
Any group of spore-producing organisms feeding on organic matter; part of the Fungi kingdom
Define yeast
A microscopic unicellular fungus; usually facultative anaerobes; that reproduce by budding and are capable of fermentation
Define mold
Usually aerobic multicellular filamentous fungi
Define thallus
An organism with no apical growth (not differentiated into stem and leaves or whatever); lacks true roots and a vascular system
Define mycelium
The vegetative part of a fungus, consisting of a network of hyphae
Define conidia
A spore in asexual or sexual reproduction that detaches from the parent and germinates into a new mold
Define hypha
Long filament structures that absorb nutrients or are used for reproductive function
Define ascus
Sac containing ascospores (the reproductive spore of ascomycota)
Define Basidiospores
A sexually produced fungal spore from the phylum Basidiomycota
Define Zygospores
A sexually produced fungal spore from the phylum Mucoromycota
Define plasmogamy
haploid donor nucleus (+) penetrates cytoplasm of recipient cell (-)
Karyogamy
(+) and (-) nuclei fuse to form diploid zygote
Meiosis
diploid nucleus produces haploid nuclei (sexual spores)
Mycosis
The stage of fungal sexual reproduction in which two haploid nuclei fuse to form a diploid zygote
List the defining characteristics of fungi; differentiate fungi from bacteria
Fungi:
Eukaryotic
Sterols present in cell membrane
Cell walls contain chitin; glucans; mannans
Sexual and asexual reproductive spores
Metabolism: Limited to heterotrophic; aerobic, facultatively anaerobic
Bacteria:
Prokaryotic
Sterols absent, except in mycoplasma
Cell walls contain peptidoglycan
Endospores (not for reproduction); some asexual reproductive spores
Metabolism: Heterotrophic, autotrophic; aerobic, facultatively anaerobic, anaerobic
medically important phyla
Mucoromycota
Microsporidia
Ascomycota
Basidiomycota
Mucoromycota Reproduction
Produced asexually: sporangiospore
Produced sexually: zygospore
Microsporidia Reproduction
Produced asexually: sporangiospore
Produced sexually: none observed
Ascomycota Reproduction
Produced asexually: conidiospore
Produced sexually: ascospore
Basidiomycota Reproduction
Produced asexually: conidiospores
Produced sexually: basidiospores
Systemic mycoses
deep within the body, affecting tissues/organs
Subcutaneous mycoses
beneath the skin
Cutaneous mycoses
affect hair, skin, and nails
Superficial mycoses
localized (e.g. hair shafts)
Opportunistic mycoses
fungi harmless in normal habitat but pathogenic in a compromised host
Describe the life cycle of a Mucoromycete
Asexual: A hypha produces a sporangium, which bursts to release sporangiospores. A sporangiospore germinates and produces hyphae; a vegetative mycelium grows.
Sexual: Gametes form at the top of a hypha and plasmogamy occurs. A zygospore forms and karyogamy and meiosis occurs. The zygote produces a sporangium, which then releases spores, and the whole thing starts all over.
Describe the life cycle of a Microsporidian
Only asexual reproduction: Sporangiospores are ingested or inhaled by an organism, and the spore injects a tube into the host cell. The spore’s cytoplasm and nucleus travels through the tube and into the host cell. The cytoplasm grows and the nuclei reproduce. The cytoplasm breaks up to form spores, which are then released by the cell.
Describe the life cycle of an ascomycete
Asexual: a hypha produces a conidiophore, and conidia are released form it. A conidium germinates to produce a hyphae; vegetative mycelium grows.
Sexual: from the mycelium, plasmogamy occurs, then karyogamy (an ascus forms), then meiosis then mitosis. The ascus opens to release ascospores, and the ascospores can germinate to produce hyphae.
Describe the life cycle of a basidiomycete
Asexual: A hyphal fragment breaks off vegetative mycelium, and the fragment grows to produce new mycelium.
Sexual: Plasmogamy occurs from the vegetative mycelium. A fruiting sturtuce (“mushroom”) develops. Karyogamy occurs, and Basidia form diploid nuclei. Basidiospores are formed by meiosis, then they mature and are discharged. They can germinate and produce hyphae.
Yeasts
nonfilamentous and unicellular. Budding yeasts divide unevenly and fission yeasts divide evenly.
Molds
multicellular filamentous fungi that are usually aerobic.
Dimorphic fungi
grow as molds below 37 degrees C and as yeast above.
Explain how hyphae and spores relate to fungal growth
Spores can germinate to make hyphae, which can grow to create mycelium.
