Chapter 21: Fungi Flashcards
What is a hypha?
a tube of a filament in a fungus
What is a mycelium?
visible mass of hyphae
What are fungi cell walls made of?
chitin
What are the 2 modes of nutrition for fungi?
parasitic and saprophytic
Are fungi heterotrophic or autotrophic?
heterotrophic
What is a parasite?
an organism that feeds off of a living host
What is a saprophyte?
an organism that feeds off of dead organic matter
What are the two types of parasite?
obligate parasite - only lives on a live host (can cause harm)
facultative parasite - may kill the host
What are saprophytic fungi known as in ecology?
decomposers
What is the difference between edible fungi and poisonous fungi?
edible - can be eaten and digested
poisonous - can be eaten but not digested, it causes harm to the body
What is an example of an edible fungi?
truffles
What is an example of a poisonous fungi?
death cap
Name the two fungi studied.
rhizopus
sacchoromyces
How does rhizopus get its food?
secretes enzymes into its environment
lives off starchy food
saprophyte
What is the function of hyphae?
digests the substrate on which they grow
What is the function of rhizoids?
provide extra surface area for absorption of the digested material
What is the function of the stolon?
allows rhizopus to spread sideways
hyphae are multinucleic, what does this mean?
they have no cross walls and multiple nuclei (n)
What is the function of the sporangium?
produces spores
What is the mycelium?
hyphae, rhizoids together
How does rhizopus reproduce?
asexually - sporulation
sexually - gamete joining
What is sporulation?
the sporangium opens to release spores, each spore blows away and it lands on a substrate, if the substrate is suitable, it grows into a new hyphae and mycelium
Explain the sexual reproduction of rhizopus. 12 steps
- hyphae from opposite strains grow close together (+ and - )
- swelling from opposide each other form
- the swellings touch
- nuclei move into each swelling forming progametangia
- cross walls form to produce gametangia which are held together by suspensors
- walls between gametangia dissolve
- fertilisation occurs and produces many diploid zygote nuclei
- a tough walled black zygospore forms these nuclei
- zygospores can remain dormant for a long time
- in favourable conditions zygospores germinate by meiosis
- haploid hyphae grows, sporangiophore, sporangium
- spores are released from sporangium
What is a progemetangia?
nuclei move into swelling that are touching
What is a gametangium?
when the nuclei in the swellings join to form one swelling
What is a zygospore?
a spore that is dormant until favourable conditions arise
What is another name for yeast?
sacchoromyces
How does yeast get its food?
anaerobic respiration
What is the equation for anaerobic respiration?
glucose —— 2 ethanol + 2 carbon dioxide
How does yeast reproduce?
asexually - budding
Explain budding.
- parent cell divides by meiosis to form another nucleus
- a bud forms on the cell and one nucleus enters the bud
- eventually the bud will detatch from the cell to make 2 daughter cells
What are 2 benefits and 2 disadvantages of fungi?
benefits - yeast produces alcohol, food
disadvantages - destroys material, causes disease
