31 Flashcards
yeast
multicellular filaments and single cells
bodies of these fungi typically form a network of tiny filaments called
hyphae
cell walls are strengthened by
chitin
septa
hyphae are divided into cells by cross-walls
two types of mycorrhizal fungi
ectomycorrhizal fungi
arbuscular fungi
mycorrhizal fungi colonize soil by dispersing haploid cells called
spores
the nuclei of fungal hyphae and the spores of most fungi are ___
haploid
the union of the cytoplasm to 2 parent mycelia is known as
plasmogamy
fungi reproduction
fungi can reproduce sexually and asexually
deuteromycetes
fungi lacking sexual reproduction
many fungi reproduce asexually by growing as filamentous fungi that produce (haploid) spores by mitosis; these are referred to as ____
molds
fungi are part of what clade
opisthokonts
fungi
heterotrophs that acquire nutrients by absorption
chytrids
a group of fungi with flagellated spores
lichens
highly integrated symbiotic associations of fungi and algae or cyanobacteria
Saprophytes or saprobes
feed on dead tissues or organic waste (decomposers)
Symbionts
mutually beneficial relationship between a fungus and another organism
Parasites
feeding on living tissue of a host.
• Parasites that cause disease are called pathogens.
Phylum Chytridiomycota
‘simple’ fungi
Chytrids are found in freshwater and terrestrial habitats
They can be decomposers, parasites, or mutualists
Chytrids are unique among fungi in having flagellated, motile spores, called
zoospores
The zygomycetes are named for their sexually produced ______
zygosporangia
Develops into zygosporangium in which _____ develops
zygospore
Glomeromycetes are a small group of
obligate symbionts
yeasts
• Unicellular ascomycetes
• Most reproduce asexually by budding
• Yeasts can ferment carbohydrates
– Break down glucose into ethanol and CO2
what are lichens?
Symbiotic associations between a fungus and a photosynthetic partner
• Cyanobacteria, green algae, or sometimes both
– Most are mutualistic
what are 3 types of lichen?
- Crustose lichens form flat
crusty plates. - Foliose lichens are leafy in appearance, although lobed or branched structures are not true leaves.
- Fruticose lichens are even more finely branched and may hang down like beards from branches or grow up from the ground like tiny shrubs.
mycosis
an infection in an animal by a fungal parasite
mycelia
networks of branched hyphae adapted for absorption
hyphae
the individual filaments that make up a mycelium
characteristics of hyphae
- Tubular
- Hard wall of chitin
- Crosswalls may form compartments (± cells)
- Multinucleate
- Grow at tips
how does hyphae grow?
Hyphae grow from their tips
mycelia have a
huge surface area
Absorptive Feeding
Fungi get carbon from organic sources
– Hyphal tips release enzymes
– Enzymatic breakdown of substrate
– Products diffuse back into hyphae
how does digestion work for fungi
Occurs almost exclusively extracellularly
– Digestive enzymes are secreted across cell membranes
– Then digestion products are absorbed
– Typically the fungus grows through its food (soil or organism)
Nematode-trapping fungi
hyphae adapted for trapping and killing prey
plasmogamy
union of 2 parent mycelia
karyogamy
nuclear fusion
what do molds do
produce haploid spores by mitosis and form mycelia
Phylum Zygomycota
The zygomycetes exhibit great diversity of life histories
They include fast-growing molds,
parasites, and commensal symbionts
Phylum Glomeromycota
- Glomeromycetes are a small group of obligate symbionts
- Form intracellular associAartions with plant roots called arbuscular mycorrhizae •Cannot survive in absence of host plant •No evidence of sexual reproduction
Phylum Ascomycota
Contain about 75% of the known fungi:”sac fungi” because they produce sexual spores in asci, asexual is also common
Phylum Basidiomycota
Aka club fungi, ~30,000 species •Sexual reproduction = basidia •Asexual reproduction is uncommon
_____ fungi are decomposers.
Saprobic
Molecular evidence suggests that fungi _____.
and animals have a common ancestor
Fungi are said to be absorptive heterotrophs rather than ingestive ones because they ____________.
digest organic matter outside their bodies
In contrast to plants, the cell walls of fungi are composed of _____.
chitin
The hyphae of parasitic fungi that are modified to penetrate and absorb nutrients from host tissue are called _____.
haustoria
There is a fungus in Oregon that covers 2,200 acres! The bulk of this fungus is most likely ____________.
mycelium
In fungi, the function of the mycelium is ____________.
obtaining food
Some scum was found growing near the edge of a pond. Under a microscope, each of its cells was found to contain two nuclei. This means the scum must be _____.
fungus
Which one of the following statements about fungi is FALSE?
Fungal spores are diploid cells in virtually all species.
Hyphae with two nuclei per cell are called _____.
dikaryotic
Fungi of the phylum Chytridiomycota were once placed in the kingdom Protista because they have _____.
flagellated cells
Fungi are classified on the basis of ____________.
their sexual stage
Fungi of the phylum Zygomycota are recognized on the basis of their production of ______ during sexual reproduction.
a dikaryotic structure
The tips of sexual hyphae in zygomycetes such as black bread mold, Rhizopus, serve as _____.
gametangia
The asexual spores produced by members of the phylum Ascomycota are called _____.
conidia
An ascus is _____.
a saclike cell containing spores
Under a microscope, a piece of mushroom would look most like _____.
tangle of string
in mushrooms, karyogamy results in the formation of the __________ phase.
diploid
The next time you have cream of mushroom soup, you can say, “What a delicious __________.”
basidiomycete
The mushroom in a basidiomycete life cycle serves the same function as the ____________ in the ascomycete life cycle, which is to ____________.
ascocarp … scatter sexually produced spores
While hiking through a forest, you discover a fungus growing on the remains of a decaying tree trunk. You hypothesize that it is a basidiomycete fungus because it resembles a mushroom in shape and size. If your logic is correct, microscopic analysis of the tissue found in the stalk of this fungus will reveal the presence of _____.
dikaryotic cells with haploid nuclei
The gills of a mushroom (basidiomycete) are specialized for _____.
reproduction
The basidiomycete fungi produce spores _____.
on a club-shaped cell
Where and when does fertilization occur in the mushroom life cycle?
in a mushroom, when the nuclei of a dikaryotic cell fuse
Lichens are _____.
symbiotic associations of photosynthesizers and fungi
Which of the following could NOT be involved in a lichen symbiosis?
dinoflagellate
Aspergillus soyae, one of the fungi used to make soy sauce (shoyu) has no known sexual cycle. It is therefore classified as one of the ____________.
deuteromycetes
You are hiking through a bog in northern Maine and notice what appears to be moss growing on the tamarack trees. On closer inspection, you see that the “moss” is composed of translucent (clear) filaments with interspersed spherical green cells. This moss must be _____.
a lichen
We know the yeasts are not protists because under certain conditions they form short filaments of cells, or hyphae. Additional evidence that they are fungi is that they _____.
produce asci when they reproduce sexually
During the American Revolution, the British lost more ships to ______ than to sinking by the enemy.
fungal rot
A dramatic example of the pathogenicity of certain fungi is the virtual elimination of the American elm by _____.
an ascomycete
ascomycete
a fungus whose spores develop within asci. The ascomycetes include most molds, mildews, and yeasts, the fungal component of most lichens, and a few large forms such as morels and truffles.
“sac fungi”
what are the reproductive structures of fungi?
the mushroom “cap” is where the haploid spores are produced
septa
hyphae divided into cells by cross walls
coenocytic fungi
continuous cytoplasmic mass having hundreds or thousands of nuclei
mycorrhizae
mutually beneficial relationship between fungus and plant roots
deuteromycetes
fungi lacking sexual reproduction
what clade are fungi in
opisthokonts
heterokaryotic
cells have haploid nuclei from two parents
what was the ancestor of fungi
aquatic, single celled and flagellated protisit
all fungi are
symbiotic
which of the following cells or structures are associated with asexual reproduction in fungi?
conidiophores
the closest relatives of fungi are thought to be the
animals
the most important adaptive advantage associated with the filamentous nature of fungal mycelia is
an extensive surface area well suited for invasive growth and absorptive nutrition
conidia
asexual spores of the Ascomycetes
