Fungi Flashcards
are fungi eukaryotic?
yes
what are the 3 major groups of fungi?
moulds, yeast, mushrooms
are fungi ubiqutious?
yes
how do fungi survive?
- they secrete hydrolytic enzymes that allow them to solubilise substances
- they are usually aerobic
- can be facultative anaerobe (can obtain energy by fermentation - yeast)
fungi can be either…
saprophytic or parasitic
what is a saprophytic fungi?
uses dead organic matter as a nutrient source
what is a parasitic fungi?
live on another organism
what is the fungal cell wall like?
very rigid - provides rigidity and structure, they have lots of layers, 80-90% polysaccharide, also contains chitin, glucans (mannans, galactosans), cellulose, mannans
what is the fungal cell membrane like?
similar to eukaryotes, has 6% sterol composition, ergosterol instead of cholestrol which could be a selective target for drug design, it also regulates osmotic pressure
what is the shape of yeast?
spherical, oval or cylindrical in shape, 3-30micrometers, they are unicellular fungi , it can produce sexually and asexually
what is the shape of moulds?
they consist of branched, thread like filaments called hyphae which form a mycelium.
it has lots of nuclei - multinucleate so can rapidly divide
what are hyphae?
branched, thread like filaments
what do all the hyphae together form?
a mycelium
what is the difference between septate and coenocytic?
septate (with cross walls) or coenocytic (continous cytoplasm)
when do mushrooms occur?
when conditions are favourable
how do fungi reproduce sexually?
a mixing of genetic material occurs so that the offspring exhibit traits of both arents.
many species of fungal can use both sexual and asexual reproduction at different times. True or false?
tru
what mechanism do yeast use to asexually reproduce?
fission and budding
moulds have unique reproductive structure. true or false
true
can yeast become resistant really quickly?
yes
how do moulds reproduce?
asexually, exospores (conidia) are involved. they occur from fusion of unicellular gametes or specialised hyphae
what do spores depend on?
specie
what are the 2 types of spores?
acospores - formed in enclosed sac
- basidiospores - formed in club shaped baidium
what is yeast used in industrially?
fermentation (beer, wine bread) & genetic engineering
what can molds do medically to us?
colonise us - causing superficial (surface layer of the body) mycoses
Hypersensitivity - fungal spores, mycelial fragments
-toxins
what is a candidiasis?
a yeast infection, they can be superficial such as oral or vaginal thrush, or systemic and potentially life-threatening diseases.
who are most vulnerable to candida infections?
immunocompromised, such as cancer, transplant, and AIDS patients, are vulnerable
how is candidiasis treated?
commonly treated with topical clotrimazole, topical nystatin, fluconazole and topical ketoconazole.
what can we target in fungi to get rid of them?
ergosterol, bc human cell dont have that, its found in membranes instead of cholestrol
some antifungal drugs and causse they target
Polyoxins: inhibit chitin biosynthesis (not used clinically)
5-fluorocytosine: nucleic acid synthesis inhibitor
Emergence of resistance
what is yeasts’ dimorphism?
yeast can either grow as a yeast (single cells)
or they can form a mycelial and grow together.
at body temperature, how does candida albicans grow?
it forms a mycelial, making it more pathogenic that can invade our tissues, allow it to reproduce more rapidly , gives a competitive advantage
