Fungi Flashcards
What are fungi?
Mushrooms, mildews, moulds and yeasts
Are fungi eukaryotic or prokaryotic?
Eukaryotic (nucleus, cell organelles enclosed by membrane)
What is the study of fungi?
Mycology
What are fungi cell walls made from?
Chitin
What is a difference between plant and fungi walls?
Fungi cell walls are made from a carb called chitin, plant cells walls are made of cellulose
What are fungi made up of?
Tubes called hyphae
What do hyphae form?
A visible mass called mycelium
Do fungi have chlorophyll ?
No
Are fungi heterotrophic or autotrophic?
Heterotrophic (take in food)
What types of heterotrophs can fungi be?
Saprophytic (absorb food from dead host) or parasitic (live on living host)
What are examples of fungal parasites that cause disease?
Athlete’s foot and ringworm
What are obligate parasites?
Fungi causing mildews, smuts and rust that can only live on live hosts and do not normally kill their host
What are facultative parasites?
Fungi causing soft rots in fruit, it may kill the host and live on its remains
Are most fungi saprophytic or parasitic?
Saprophytic
Where are saprophytic fungi commonly found?
Soil and on rotting leaves, trees and dead animals
What are examples of saprophytic fungi?
Mushrooms and moulds
What do saprophytic fungi act as?
Decomposers
Why are saprophytic fungi good for the environment?
As the material is digested, minerals are released and recycled.
What are above ground edible fungi?
Standard field mushroom and morels
What are underground edible fungi?
Truffles
What are the most poisonous mushrooms?
Death cap and the destroying angel
What is rhizopus?
Saprophyte of starchy foods (e.g. bread, veg peelings).
What does the rhizopus secrete?
Enzymes
How does bread mould fungus appear?
Bread mould fungus appears as black circular patches.
What does rhizopus consist of ?
Hyphae
Do rhizopus have cross walls?
No cross walls (asepate)
Do rhizopus have multiple or one nucleus?
Multinucleated
Are rhizopus nuclei haploid or diploid?
Haploid
What is a mass of hyphae called?
Mycelium
What is a stolon?
A stolon is an aerial hypha which allows the fungus to spread more rapidly.
What are rhizoids?
Rhizoids are hyphae that grow into the substrate and provide extra surface area for absorption (enzymes). Also for anchorage
What is the process of asexual reproduction for a rhizopus?
- Some hyphae grow up from the surface of the substrate. These are called sporangiophores.
- Their tip swells to produce a sporangium whose contents divide by mitosis to form numerous spores.
- Each spore has at least one haploid nucleus.
- The base of the sporangium is a wall called columella.
- The columella surrounds a swollen area called the apophysis.
- In dry conditions, the black sporangium dries out and opens to release many spores.
- Each spore blows away and grows into a new hypha and mycelium if it lands on a suitable substrate.
What two strains can rhizopus exist as?
Plus and minus strains
What is the process of sexual reproduction in rhizopus?
- Hyphae from opposite strains grow close together.
- Swellings form opposite each other.
- The swellings touch.
- Nuclei move into each swelling forming progametangia.
- Cross walls form to produce gametangia, which are held in place by suspensors.
- The walls between the gametangia dissolve.
- Many fertilisations produce a number of diploid zygote nuclei.
- The zygospore (which is diploid) can remain dormant for a long time.
- When conditions are suitable the zygospore germinates by meiosis.
- A haploid hypha grows out of the zygospore and produces a sporangium at the tip.
- The sporangium releases many haploid spores, which blow away to produce new hyphae and mycelia.
How many cells do yeast have?
Single called (unicellular) fungi
What shape is yeast?
Oval shape
What are yeast walls made of ?
Chitin
How many nuclei do yeast have?
One nucleus
How do yeast respire?
Anaerobically (without oxygen)
What is the formula for alcohol production with yeast?
Glucose —> 2 ethanol + 2 carbon dioxide
How does the asexual reproduction of yeast occur?
By budding
What is the process of asexual reproduction in yeast?
- parent cell divides by mitosis, one nucleus and some cytoplasm enter bud
- bud may separate to form individual yeast cell
- sometimes bud remains attached to parent cell
- each new bud may divide again
- a colony can form
- this occurs when yeast is growing rapidly
- the colony is temporary, later divides into single cells
What are economic benefits of fungi?
- produce alcohols e.g wine and beer
- produce mushrooms to sell and eat
What are disadvantages of fungi?
- fungi (rhizopus) cause food spoilage e.g bread mould
- fungal diseases e.g athletes foot, ringworm
