Mycology Flashcards
Mycology refers to the study of ______
Fungi
Mycoses are ______
fungal infections.
Fungi are a diverse group of ____tic and ____tic eukaryotic organisms.
saprophy
parasi
Saprophytic means deriving nourishment from _____
dead organic matter
Fungi are approximately ____ in size
4um
CELL STRUCTURE of fungi
Cell membrane
-The fungal cell membrane contains ______ rather than the cholesterol found in mammalian membranes.
ergosterol
Cell wall of fungi
-The fungal cell wall consists primarily of ____ (not _____ as in bacteria)
-The fungal cell wall contains other polysaccharides as well, the most important of which is ____ , a long polymer of D-glucose.
chitin
peptidoglycan
β-glucan
Chitin is a polysaccharide composed of long chains of _____
N-acetylglucosamine.
Fungal characteristics
-Most fungi are obligate ____; some are ______; but none are ______
aerobes
facultative anaerobes
obligate anaerobes.
-only some fungi are chemoheterotrophs.
T/F
F
All fungi are
chemoheterotrophs means They require _______—hence their frequent association with _____
an organic source of carbon
decaying matter.
The natural habitat of most fungi is the ____ or _____.
An important exception is _____, which is part of the ________
soil
decaying organic matter
Candida albicans
normal human flora.
_______ is the site of action of antifungal drugs, amphotericin B & azole group.
Ergosterol
CLASSIFICATION OF FUNGI
Fungi are morphologically classified into:
*____-like fungi
*____-like fungi
mold
Yeast
mold-like fungi: e.g ____,____
*Yeast-like fungi e.g _________
Mucor, Rhizopus
Saccharomyces cerevisiae
Molds ( ______ fungi )
-The vegetative body of mold-like fungi is typically a ______ with ______
filamentous
mass of threads with many branches
Molds
Mass+ branches
This mass is called a ______, which grows by _______ and _____
-The branches/threads (____) are actually ____ cells that, in some fungi, are partitioned into segments (septate), whereas, in other fungi, the hyphae are uninterrupted by cross-walls (nonseptate).
mycelium
branching and tip elongation.
hyphae
tubular
In septate fungi, the cytoplasm of the hyphae is discontinuous.
T/F
F
Even in septate fungi, the septae are perforated so that the cytoplasm of the hyphae is continuous.
Molds
Their ____ on agar aids their diagnosis by their ______ and ______ produced
colony
appearance and pigments
YEASTS
-These fungi exist as populations of (single or double ?) , (connected or unconnected?) ,______ shaped cells.
-They reproduce by ______ known as _____.
Single
unconnected
spheroid
the formation of buds
blastospores
YEASTS
They are also called budding yeast
Why?
They appear with daughter cells attached
Yeasts colonies resemble bacterial colonies in appearance
T/F
T
Yeasts colonies resemble bacterial colonies in appearance and in consistency
Dimorphic fungi
-Some fungal species, especially those that cause ____, are dimorphic, being yeast-like in one environment and mold-like in another
-This is usually dependent on _____ and as such, they are also called ____ .
systemic mycoses
temperature
thermally dimorphic
Dimorphic fungi
Molds in the environment (_______ phase) __-__C.
-Yeast (________ phase) __C.
-Examples; ________,______,______
saprophytic ; 25 – 27
parasitic/pathologic; 37
Histoplasma capsulatum, Blastomyces, Talaromyces marneffei
Fungal reproduction
-______ is the principal means by which fungi reproduce and spread through the environment.
Sporulation
Fungal sporulation
Spores can be generated only asexually
T/F
F
Spores can be generated either asexually or sexually
Fungal sporulation
the spores are metabolically active
T/F
F
Metabolically dormant
Fungal spores are protected cells with (thin or thick ?) cells walls and (easy or difficult?) to destroy.
They also tend to be released in (small or large?) amounts.
Thick
Difficult
Large
Asexual Sporulation:
-Asexual spores (aka _____ ) are formed by (mitosis or meiosis?) in or on specialized hyphae (_______ )
conidia
mitosis
conidiophores
The color of a typical fungal colony seen on bread, fruit, or culture plate is caused by the _____
conidia.
Conidia can be easily detached from their underlying mycelia
T/F
T
Some important conidia include:
*_______
*________
*_______
*_________
Arthrospores
Chlamydospores
Blastospores
Sporangiospores
Arthrospores, which arise by ________________ and are the mode of transmission of __________
fragmentation of the ends of hyphae
Coccidioides immitis
Chlamydospores, which are ____ shape, (thin or thick?)-walled, and quite resistant
Round
Thick
Blastospores, which are formed by the _______
budding process
C. Albicans, can form multiple buds that _____, thus producing ________ called ______, which can be used for identification
do not detach
sausagelike chains
pseudohyphae
Sporangiospores, which are formed within a sac ( _____ ) on a stalk by molds such as ______,___
sporangium
Rhizopus and Mucor
Sexual Sporulation:
-Some fungi reproduce sexually by _____ and forming ______ (e.g., ____spores, _____spores, and ____spores).
mating
sexual spores
zygospores, ascospores, and basidiospores
Zygospores are (single or double ?) (small or large?) spores with (thin or thick?) walls
Single
Large
Thick
ascospores are formed in a sac called ____
ascus