Chapter 24: Fungi Flashcards
what supergroup are the fungi apart of?
opistakonta
are fungi more closely related to plants or animals?
animals
what are the major characteristics of fungi?
cell wall of chitin, not capable of photosynthesis, heterotrophic, store excess sugars as glycogen, multinucleate, fungi live underground and what you see is the reproductive body, eukaryotes
what fungi are unicellular?
yeasts
what are the different components of fungi?
hypha, mycelium, sclerotium
hyphae
tublar structures, hard wall of chitin, multinucleate, grow at their tips. individual parts of the mycelium
mycelium
aggregate of hyphae
sclerotium
hardened mass of mycelium that generally serves as an overwintering stage. a dormant phase in the winter
what are the different ways fungi are heterotrophic?
saprobes, mutualistic symbiont, parasitic symbiont
what are the uses, ecological, and problems of fungi in their eviroments?
uses: medicine and food
ecological: major decomposers, symbiotic relationships
problems: some are deadly, diseases, destroy crops and books
how do fungi eat their food?
release enzymes to break down the food and then diffuse the nutrients into their hyphae, store their food in the form of lipids or glycogen
spores
not seeds, asexually produced through mitosis or sexually produced through meisosis
what is the purpose of spores?
allows fungus to move to a new food source, means of introducing new genetic variation, scatter and disperse their genes into a new area
where can spores be located?
spores can be located directly on the hyphae, inside the sporangia, or on the fruiting body
what are the four main groups of fungi?
chytridiomycota, zygomycota, ascomycota, and basidiomycota
chytridiomycota (chytrids)
simple and most primitive fungi, have one flagella, produce motile spores, mostly saprobes and parasites in aquatic habitats, very similar to protists but have characteristics of fungi, most are unicellular, but a few are multi but are coenocytic
zygomycota (zygote)
spore through sexual reproduction is called a zygosporangia, through asexual is called a sporangia. hyphae is coenocytic, grow rapidly, decomposers, pathogens, and some for mycorhizzal associations with plants, their spores have thick coats to protect from desiccation and other hazards, and are able to remain dormant until their environment is stable
asexual life cycle of a zygomycota
sporangiophore produces sporangia, which is dispersed and germinated
sexual life cycle of a zygomycota
two different strands of hyphae come together and before fusing form a gametergium. plasmogomy occurs, karyogomy occurs. spore is now a diploid and undergoes meiosis. germination occurs
ascomycota
sexual reproduction produces an asci or ascus. includes the cup fungi, morels, and truffles. asexual is more frequent, male = antheridium, female = ascogonium, fruiting body is called ascocarp. important plants parasites, yeast, decomposers and found in most lichens, hyphae has perforated septa,
asexual life cycle of an ascomycota
one cell will break off and produce its own system
sexual life cycle of an ascomycota
one strand will be the antheridium and the other will be the ascogomium. plasmogamy, karyogamy, meiosis occurs, mitosis occurs and 8 spores are formed. ascospores are released, germinate, and make their own hyphae
basidiomycota
club fungi, sexual reproduction through basdia, dikaryotic mycelia, includes mushrooms, polypores, puffballs, boletes, and bird nest fungi. decomposers, pathogens, form mycorrhizal associations, most edible fungi,
molds
rapidly grow, asexual spores, have human significance in food spoilage, food products, and antibiotics
beneficial effects of fungi
decomposition for nutrient and carbon recycling, can be used to produce food, drugs, antibiotics, acids, alcohol
harmful effects of fungi
destruction of food, paper, lumber, cloth, animal and human diseases and allergies, poisonous, and plant diseases
mycorrhizal association
mutualistic fungal association with a plant. hyphae can invade root cells or invade the root without penetrating the cells, about 90% of vascular plant species has this association
lichens
mutualistic association between a fungus and an algae or cyanobacteria - neither can survive without the other. there are three types, can survive in unusual and hostile environments, can grow where roots cannot penetrate, can remain dormant during droughts and reactivate when there is water, belong to Basidiomycota or Ascomycota
foliose lichens
are leafy in appearance, although lobed or branched structures are not true leaves.
crustose lichens
form flat crusty plates.
fruticose lichens
are even more finely branched and may hang down like beards from branches or grow up from the ground like tiny shrubs.
cell structure and function of fungi
have membrane bound organelles, DNA wrapped around histones, have mitochondria and internal membranes, no chloroplasts or chlorophyll
what does the cell wall for fungi do?
protects from desiccation and predators
septa
most hyphae are divided into seperate cells by endwalls
perferatted septa
allow for rapid flow of nutrients
coenocytic hyphae
large cells containing many nuclei
what enviroments do fungi thrive in?
in moist and slightly acidic environments. can survive with or without light and most are obligate anaerobes with the exception of chytrids (obligate anaerobes) and yeast (facultative anaerobes).
how do fungi eat?
digestion preceeds ingestion. exoenzymes are transported out of the hyphae where they process nutrients in the enviroment. smaller molecules produced by this external digestion are absorbed through the large surface area of the mycelium. they store their polycacchrides (carbs) into glygogen
homothallic
self-fertilize
heterothallic
needs two different mating types
plasmogamy
union of the cytoplasm
karyogamy
haploid nuclei fuse to form a diploid zygote nuclei
ectomycorrhizae
envelope the plant in a sheath called a mantle, the fungi are around the roots
endomycorrhizae
also called arbuscle mycorrhizae, fungi are inside the roots
mycosis
fungal disease that results from infection and direct damage due to the growth and infiltration of the fungus.
mycotoxicosis
fungal poisoining of humans
mycetismus
ingestion of poisonoius mushrooms
why are fungal infections hard to treat?
you cannot treat them with antibiotics because they are eukaryotes, and fungal treatments also harm the host as well. most are superficial (on the skin) but some can result in systemic mycoses, which is a fungus that effects internal organisms - normally the lungs
