The Fungi Flashcards
What are the main characteristics of fungi?
- No Chlorophyll
- Walls contain chitin
- Not truly multicellular
- Heterotrophs (saprophytes or decomposers)
How do moulds grow?
As long tangled filaments our cells in visible colonies
What are 2 yeasts that are unicellular fungi?
- Saccrfomyoces
- Candida
How do fungi life cycles function?
Growth phase and reproductive phase
How do must fungi exist?
As hyphae, as part of a mycelium
What divides the cells of a mycelium?
Septa divides the cytoplasm
What does it mean for a fungi to be coenocytic?
Hyphae contains many nuclei
How is fungal growth influenced?
- Nutrient absorption
- Aerobic
- Room Temp its optimal growth (psychrophilic)
- Like slightly more acidic pH
What is a mycorrhizae?
Fungi that lives in a mutualistic symbiosis with plant roots
-they help take up water an minerals
What is an endophyte?
Fungal endophytes live in plant tissue, in particularly leaves.
-may produce toxins
How do fungi reproduce?
Mostly via spore formation
- asexual
- in fruiting bodies
Where do the spores develop?
In sacs called sporangia
- some spores are produced not in sacs
What does the fragmentation of hyphae yield?
Arthrospores
When do fungi reproduce sexually?
In harsh and changing conditions
-more favourable conditions they are more likely to reproduce asexually
What is the group of more advanced fungi?
Dikaryamycota
What can dikaryamycota be subdivided into?
Basidiomycota: Mushrooms
Ascomycota: Moulds, cheese, fruit+bread
What are zygomycetes?
Terrestrial fungi that grow as mould on bread and produce
-during sexual reproduction they form a heterokaryotic diploid zygospore
What accounts for 75% of final species?
Ascomycetes
- yeast
- some mushrooms
- mould
What do ascomycetes produce?
Conidia through asecual production (spore lines, not sacs)
Ascospores through sexual reproduction (in sacs)
What are lichens?
mutualistic association between a fungus and a photosynthetic organism
What do basidiomycetes usually produce?
Club fungi (typical mushroom) and puffballs
Where are sexual spores produced on basidiomycetes?
Basidia on the gills of a mushroom cap contain sexually produced basidiospore
What shape is the fungus in most of the time?
Most of the time the fungus is the cell shape of the hyphae
-true mushroom shape is only a result when it wants to reproduce
What does the term yeast mean?
Represents a term for any single celled stage of fungus
Which type of fungus is a model eukaryotic organism?
Saccharomyces cerevisiae
- ferments sugars
- used in bread and alcohol production
What is a mycotoxin?
A fungal toxin
What is ergotism?
Caused by claviceps purpurea which grows on grains
-ergot deposited in the grain causes numbness, hot and cold sensations, seizures, paralysis of nerve endings!
What does amanita cause ?
About 90% of death from mushrooms ingestion
- produces cramping, vomiting, and diarrhea
- taking in the intoxication
What is dermatophytosis?
Is an infection of the body surface
- transmitted by contact with domestic animals
- symptoms are blister-like lesions with a thin fluid discharge
- treatment often involves changing the skin environment
What is candidiasis?
A mild superficial infection
What causes candidiasis?
Candida albicans causes immune system is compromised or microbial populations in the body change
What is sporotrichosis?
Is an occupational hazard. can occur in people who work with wood and wood products and soil
-infection with spores can cause pus-filled lesions
What is cryptococcosis?
Usually occurs in immunocompromised individuals
-due to inhaled cells penetrate to the air sacs of the lungs
What causes cryptococcosis?
Cryptoccus neoformans
- found in urban soil and pigeon droppings
- cells rarely pass the BBB
What is Histoplasmosis and what causes it?
Can produce a systemic disease. Most people suffer influenza like symptoms
- caused by hostoplasma capsulatum
- found in dry, dusty soil, chicken coops and bat caves
What is aspergillosis and what causes it?
When conidia enter the body and grow as mycelium and occur in immunesupressde people
- caused by aspergillum fumigatus
- affect heart or brain causing meningitis
