Fungi Flashcards
In relation to micro-organisms such as bacteria and fungi, describe their
distribution in nature.
they can survive in all habitats
they are found everywhere
Explain sterility.
absence of all (micro) organisms
Explain asepsis.
absence of pathogens
Definitioin of sparophytic?
(organism that) feeds on dead organic matter
Definition of parasitic?
(organism that) feeds on another living organism causing it harm
Sexual reproduction in Rhizopus results in the formation of a thick-walled, dormant structure that can survive a long time in unsuitable conditions. What is the name of this structure?
zygospore
What happens to the zygospore if
suitable conditions return?
germinates
Give 2 examples of beneficial fungi.
edible mushrooms
yeast
Are fungi eukaryotic or prokaryotic? Explain.
eukaryotic: have a nucleus and membrane bound organelles
Fungi have cell walls usually made up of a carbohydrate called?
chitin
Are fungi heterotrophic or autotrophic? Explain.
heterotrophic: dont make their own food/they take in food from other organisms
How do fungi reproduce?
spores
Fungi are made up of threads/tubes called?
hyphae
Hyphae form a visible mass called?
mycelium
In terms of nutrition, fungi are either?
parasitic or saprophytic
Name the 2 types of parasites.
obligate, facultative
Definition of obligate parasites? Give an eg.
get food only from a live host (don’t kill host)
Eg: athletes foot
Definition of facultative parasites? Give an eg.
get food from a dead or living host (may kill host)
Eg: wood rot
Most fungi are? Elaborate and give 2 examples.
saprophytes.
commonly found in the soil/on rotting leaves/trees/dead animals.
Eg: mushrooms, moulds (rhizopus)
Saprophytic fungi act as? Describe
decomposers: as material is digested, minerals are released and recycled.
How can you distinguish edible vs poisonous fungi?
using a key
Name two edible fungi.
field mushroom (chestnut)
truffle
Name two poisonous fungi.
destroying angel
death cap
Death from poisonous fungi is usually due to?
liver and intestine damage/failure
Mode of nutrition for rhizopus?
saprophytic/heterotrophic
Name a common bread mould.
rhizopus
Where does digestion take place for rhizopus?
outside the fungus
Function of stolon?
spread/growth/reproduction/colonisation
Function of rhizoid?
anchorage/secretion/absorption (of nutrients)
Function of spores?
(asexual) reproduction/dispersal
Definition of sporulation?
is the process of making spores
Name two unsuitable conditions.
drought
unsuitable temperatures
Explain asexual reproduction in rhizopus in 3 steps.
1) sporangium dries out in the right conditions and opens releasing spores.
2) all spores have a haploid nucleus
3) each spore grows into a new hyphae if it lands on a suitable substrate, eg bread.
Rhizopus have 2 seperate chemically opposite strains, called?
plus + and minus - strains
Explain sexual reproduction in rhizopus in steps.
1) hyphae from a + and - strain grow close, swellings grow on both strains and touch.
2) nuclei from both hyphae move into these swellings and form progametangia.
3) cross walls form to produce gametangia which are held in place by suspensors.
4) walls of gametangia dissolve and a number of fertilisations take place producing diploid zygote nuclei.
5) black zygospore forms around these nuclei.
6) in suitable condiitons, zygospore germinates by meiosis
haploid hypha grows out of zygospore
a sporangiophore and sporangium develop
Comment on shape of yeast.
round or oval
Are yeast multicellular or unicellular?
unicellular (single-celled)
Yeast have a large vacuole and ell walls made of?
chitin (carbohydrate)
Do yeast have hypha? What effect does this have?
no hypha, have a dense grainy cytoplasm and contain food vacuoles
How do yeast respire?
anaerobically (fermentation)
Do yeast produce sexually or asexually? What is this process called?
asexually, by budding
Describe in detail the process of asexual reproduction in yeast cells.
Organelles/nucleus divides,
new bud forms,
organelles/nucleus move into bud new, cell detaches (or can remain attached),
colony forms.
Two advantages of asexual reproduction?
very fast,
offspring show no variation
Two disadvantages of asexual reproduction?
increased chance of disease,
no variation
ECONOMIC IMPORTANCE OF FUNGI
- benefits?
- yeast used in brewing to produce wine/beer
- mushrooms as a food source
- baking industry
- production of antibiotics
ECONOMIC IMPORTANCE OF FUNGI
- disadvantages?
- fungal infections can destroy crops, potato blight
- fungi can spoil food, rhizopus on bread
- fungi can cause disease on humans, athletes foot
Name some asepctic techniques.
- using disinfectant (equipment/hands/bench)
- flaming equipment like forceps
- minimal opening of plates/seal them
- wear gloves/hand sanitizer/soap
