Fungi Flashcards
How are fungi saprophytic
They feed on dead or decomposing matter
How do fungi perform absorptive nutrition
Secrete digestive enzymes to breakdown complex molecules into simple molecules they can absorb
Give an example of a mutualist fungi
Lichen - Algal and fungal cells
What is another word for the mycelium mass
Thallus
What is in the cell wall of fungi
Chitin
How are fungi isogamous
No formal male and female genders - use mating types
What is the word describing which mating types can have sex with other mating types
Homothallic and Heterothallic
What is a spore - chromosomes?
A single celled biological entity that allows fungi to reproduce
Haploid
What are the 4 forms of asexual reproduction
Spore, fission, budding and fragmentation of hyphae
What is formed during the first stage of sexual reproduction - cytoplasmic fusion - n?
Dikaryon - cell with 2 haploid nuclei - n+n
What is the name given to step 2 - nuclear fusion - n?
Karyogamy - 2n
Where are the spores produced during the 3rd stage and how amy are there - meiosis - n?
Fruiting body - 4 - n
What is the last stage of sexual reproduction - n?
Germination or sporulation - n
If a spore is produced under adverse conditions - what can you say about that spore
It will be resistant to those particular conditions
Spore name for each of the 5 main phyla (GBAZC)
Glomeromycota - blastospore
Basidiomycota - basidiospore
Ascomycota - ascospore or condiospore (asexual)
Zygomycota - zygospore
Chytrids - zoospores
2 defining characteristics of glomermycota
Only reproduce asexually
Endomycorrhizal
1 defining characteristic of basidiomycota
Spores are external
Name of the fruiting body and place in which ascospores are kept in Ascomycota
Ascocarp - asci
What is unique about the spores of zygomycota
They are diploid
What is unique about the spores of chytrids
They are flagellated
2 defining characteristics of microsporidia
They are intracellular parasites and unicellular
When will Saccharomyces cerevisiae undergo sexual reproduction
When conditions are sub-optimal
What form is preferred by S. cerevisiae - how does it achieve this
Diploid
When mating types a and alpha are close enough they mate
What does the lone spore hypothesis state and why is it necessary
That a spore has the ability to switch mating type
Not all 4 haploid spores in the asci will survive so having this ability maximises success to find a mate
How are mating types attracted to one another
They produce pheromones called factors which are picked up by receptors on each mating types surface
What is the structure called that is made before complete fusion
Schmoo
Once the mating types have fused completely how is the diploid daughter cell formed
Budding
What happens when unfavourable conditions are present for S. cerevisiae
The diploid alpha and a cells undergo meiosis forming 4 stress-tolerant haploid ascospores in an ascus
When are ascospores released and what do they do
When conditions are favourable - germinate and reproduce asexually
What are the mating types called in ascomycota - when they fuse what do they form? - n?
Antheridium and ascogonium - n+n
What is formed from the continuous growth of the dikaryon in ascomycota - n?
Ascocarp - n+n
What forms at the tips of the hyphae in the ascocarp
Asci
What occurs in the asci (3) - n?
Karyogamy - 2n
Meiosis - n
Mitosis - n
Fungi Filter Hypothesis
Success of endothermic animals is a direct consequence of their ability to withstand fungal infections
Name given to fungal pathogens in the human microbiome or in specific environmental niches
Commensals and environmentals
What is dimorphism in fungi
Fungus can exist in either yeast or filamentous form
Where does superficial, cutaneous and sub-cutaneous mycoses occur
s - epidermis
c - epidermis and dermis
sc - deepest layer of the skin
Where is the infection in systematic fungi
Visceral tissue
What is an opportunistic fungi
One that is harmless normally but becomes infectious when the host is compromised
What do biofilms promote and provide
Y-M transitions
protective layer for anti-fungal resistance
What is the problem with Candidia in hospitals
Form a biofilm on catheters allowing transmission of fungal disease through catheters
What anti-fungals stop fungi from dividing and which ones kill fungi
Fungistatic and fungicidal
3 forms of antifungal treatment
- Target lipid in fungal membrane - ergosterol
- Target sugar in fungal membrane
- Target non-yeast specific cells
What does Claviceps purpurea cause - what type of fungus is it if it feeds off of a living organism
Ergot in Rye - biotrophic fungus
What functions like a peroxisome in microsporidia
Posterior vacuole
What are the polar filament and the anchoring disk necessary for
Host invasion
Microsporidia - When the spore is ingested by the host and the spore germinates, what does it release into the host cell and what structure aids this
Sporoplasm
Polar filament
What do the sporoplasm become in the host cell
Meronts
Meronts undergo cell division and form sporoblasts - what is the cell division called
Sporogony
