1.2-MORPHOLOGIC FORM Flashcards
What type of organisms are yeasts?
Unicellular
What is the shape of yeast cells?
Spherical or ellipsoidal
How do most yeasts reproduce?
Asexually by budding
What is another way some yeasts divide?
Binary fission
What is the characteristic microscopic appearance of yeasts?
Pin-bowl appearance
Can yeast grow in culture media?
Yes
At what temperatures can yeasts grow?
23-25°C (ambient) and 37°C (physiologic)
How do yeast colonies appear on media?
Moist, creamy, opaque, or pasty
Why do yeast colonies sometimes resemble bacterial colonies?
Due to their opaque and moist texture
What type of organisms are molds?
What type of organisms are molds?
How do mold colonies appear?
Fluffy, cottony, woolly, or powdery
What are the primary structural components of molds?
Hyphae and spores
What are the three types of asexual spores in molds?
Thallospores, Conidia, Spores by complex sporulation
What are the four types of sexual spores in molds?
Ascospores, Basidiospores, Zygospores, Oospores
Fungi that reproduce only asexually (anamorphs)
imperfect fungi
Give an example of imperfect fungi
Deuteromycetes
Name three fungi that belong to Deuteromycetes
Epidermophyton, Sporothrix, Scedosporium
Fungi that can produce both asexual and sexual spores
perfect fungi
The asexual form of a fungus
anamorph
The sexual form of a fungus
teleomorph
What is the anamorph of Histoplasma capsulatum?
Histoplasma capsulatum
What is the teleomorph of Histoplasma capsulatum?
Ajellomyces capsulatum
What is the anamorph of Blastomyces dermatitidis?
Blastomyces dermatitidis
What is the teleomorph of Blastomyces dermatitidis?
Ajellomyces dermatitidis
What is the anamorph of Cryptococcus neoformans?
Cryptococcus neoformans
What is the teleomorph of Cryptococcus neoformans?
Filobasidiella neoformans
What type of fungi is Cryptococcus neoformans?
Basidiomycetes
What is the sexual spore of Cryptococcus neoformans
Basidiospores
Tubular, branching filaments of fungal cells
hyphae
What do hyphae form when they join together?
Mycelium
What separates most hyphal cells?
Porous cross-walls or septa
What are the two types of hyphae based on septum presence?
Septate and Aseptate hyphae
What is another name for aseptate hyphae?
Coenocytic hyphae
What is the function of vegetative (substrate) hyphae?
Growth, nutrient absorption, and anchoring
What is the water affinity of vegetative hyphae?
Hydrophilic
What is the function of aerial hyphae?
Carry spores and extend above the medium
What is the water affinity of aerial hyphae?
Hydrophobic
Give examples of fungi with aseptate hyphae
Mucor, Absidia, Rhizopus, Rhizomucor, Cunninghamella
What fungus has antler hyphae?
Schoenleinia
What fungus has spiral hyphae?
Trichophyton mentagrophytes
What type of hyphae does Trichophyton mentagrophytes exhibit
Spiral hyphae
What type of hyphae does Microsporum audouinii exhibit?
Pectinate body
What is another term for favic chandeliers?
Antler hyphae
Which fungus has favic chandeliers (antler hyphae)?
Trichophyton schoenleinii
What type of hyphae does Microsporum canis exhibit?
Nodular organ
What type of hyphae does Epidermophyton floccosum exhibit?
Racquet hyphae
What is another term for septate hyphae?
Hyphae with cross-walls
What structures separate individual fungal cells in septate hyphae?
Septa with pores
What is another term for coenocytic hyphae?
Aseptate hyphae
What is a distinguishing feature of coenocytic hyphae?
Lack of septa
What are the key internal structures of fungal hyphae?
Nuclei, cell wall, septum (in septate hyphae), pores
A microorganism that only produces asexual spores
anamorph
What type of spores do imperfect fungi (anamorphs) produce?
Asexual spores
How are arthroconidia formed?
By fragmentation of hyphal cells
By fragmentation of hyphal cells
Arthroconidia formation
How do mature arthroconidia appear?
Square, rectangular, or barrel-shaped thick-walled cells
Give two examples of fungi that produce arthroconidia.
Coccidioides immitis, Geotrichum candidum
How are blastoconidia formed?
Through a budding process
Give two examples of fungi that produce blastoconidia
Cladosporium spp., Candida albicans
Large, thick-walled conidia that act as resistant resting spores
chlamydospores
What are the three types of chlamydospores based on location?
Terminal (at the hyphal tip), intercalary (within the hyphal strand), sessile (on the sides of hyphae)
Asexual reproductive structures produced via mitosis
conidia
How are conidia formed?
From vegetative yeast or hyphal cells, or from specialized conidiogenous cells
What are specialized hyphae that produce conidia called?
Conidiophores
What is the function of conidiogenous cells?
They generate conidia (e.g., conidiophores
What are the characteristics of microconidia?
Small, unicellular, round, elliptical, or pyriform; sessile or pedunculated
What are the characteristics of macroconidia?
Large, multiseptate, club- or spindle-shaped, thick- or thin-walled, spiny or smooth
What shapes can microconidia have?
Circular, round, oval, or teardrop-shaped
Conidia produced by a vase-shaped conidiogenous cell called a phialide
phialoconidia
What fungal group produces sporangiospores?
Zygomycetes (Mucorales)
Where are sporangiospores housed?
Inside a sac called the sporangium
What structure inside the sporangium gives rise to sporangiospores?
Columella
Name three genera that produce sporangiospores.
Rhizopus, Mucor, Absidia
What is the difference between anamorph and teleomorph?
Anamorph produces asexual spores, teleomorph produces sexual spores
Anamorph produces asexual spores, teleomorph produces sexual spores
Conidia
What sexual spores does Ajellomyces (teleomorph of Histoplasma capsulatum) produce?
Ascospores
What asexual spores does Cryptococcus neoformans produce?
Conidia
What sexual spores does Filobasidiella neoformans (teleomorph of Cryptococcus neoformans) produce?
Basidiospores
How many meiospores typically form inside an ascus?
Four to eight
What fungal group produces ascospores
Ascomycetes
Name three fungi that produce ascospores.
Ajellomyces dermatidis, Ajellomyces capsulatum, Microsporum spp.
What type of spores do Aspergillus produce asexually and sexually?
Asexual: Phialoconidia, Sexual: Ascospores
What is the function of a cleistothecium in Pseudallescheria boydii?
It protects the asci containing ascospores
Where do basidiospores form?
On a club-shaped structure called a basidium
How many meiospores typically form per basidium?
Four
Name two fungi that produce basidiospores
Cryptococcus neoformans, Malassezia spp
How are zygospores formed?
How are zygospores formed?
Name four genera that produce zygospores.
Mucor, Absidia, Rhizopus, Cunninghamella
Mucor, Absidia, Rhizopus, Cunninghamella
Sporangiospores
What sexual spores do zygomycetes produce?
Zygospores
How are oospores formed?
By heterogenous fertilization or fusion between dissimilar cells
What structure is attached to an oospore?
Antheridium
What are the two types of fungal reproduction?
Sexual and asexual reproduction
What processes occur in sexual reproduction?
Meiosis, cell fusion, nuclear fusion
What does asexual reproduction involve
Mitosis with cytoplasmic and nuclear division
From what structure are asexual spores produced?
Mycelium
What are the four major fungal phyla?
What are the four major fungal phyla?
Which fungal phylum is also known as club fungi?
Basidiomycota
Which fungal phylum includes imperfect fungi that lack a known sexual reproductive cycle?
Deuteromycota
Are zygomycetes septate or aseptate?
Aseptate
What type of asexual spores do zygomycetes produce?
Sporangiospores
What type of sexual spores do zygomycetes produce?
Zygospores
Name a clinically important genus of Zygomycota.
Rhizopus, Mucor, Absidia, Rhizomucor, Cunninghamella
What type of asexual spores do ascomycetes produce?
Conidia
What type of sexual spores do ascomycetes produce?
Ascospores
What structure produces ascospores?
Ascus
Name three medically important ascomycetes.
Aspergillus, Penicillium, Saccharomyces
What type of asexual spores do basidiomycetes produce?
Conidia or hyphal fragments
What type of sexual spores do basidiomycetes produce?
Basidiospores
What structure produces basidiospores?
Basidium
Name a medically important basidiomycete.
Cryptococcus neoformans
Why are deuteromycetes called “imperfect fungi”?
They lack a known sexual reproductive cycle.
What type of spores do deuteromycetes reproduce with?
Asexual spores (conidia)
Name an example of a deuteromycete
Candida spp., Sporothrix, Epidermophyton
What are the two main modes of fungal reproduction?
Sexual and asexual
What type of fungal spores are produced by mitosis?
Asexual spores
What type of fungal spores are produced by meiosis?
Sexual spores
The fusion of two haploid fungal cells without nuclear fusion
plasmogamy
The fusion of two nuclei in fungal cells
karyogamy
conidium that forms from the fragmentation of hyphal cells
arthroconidium
A conidium that forms through a budding process
blastoconidium
A thick-walled, resistant resting spore
chlamydospore
A conidium produced from a vase-shaped conidiogenous cell (phialide)
phialoconidium
A spore produced within a sporangium, characteristic of zygomycetes
sporangiospore
A sexual spore produced within an ascus
ascospore
A sexual spore produced on a basidium
basidiospore
A rough-walled spore produced by the fusion of two matching zygomycete types
zygospore
A spore formed by the fusion of dissimilar fungal cells
oospore