Lab 5 (fungi) Flashcards
what are the two main parts of a fungus
The vegetative body is known as the mycelium and is a web composed of many hyphae. It is commonly underground
When a fungus is ready to reproduce it grows a fruiting body. This is what is often above ground. Ex mushrooms.
where do fungi fit into eukaryote phylogeny
Fungi are in supergroup Unikonta with animals
four main groups:
- Mycorrhizal fungi (fungi from different phyla are grouped together)
- Ascomycota
- Basidiomycota
- Zygomycota (no longer a true phylum)
What is Mycorrhizae
A mutualistic symbiosis between plant roots and fungi
common in many plants
Endomycorrhizae is within and the fungal hyphae penetrate plant root cells.
Ectomycorrhizae is outside, and hyphae don’t penetrate.
describe Ascomycota
- fungi like morels, truffles, and some yeasts
- They all produce a specialized sac called an “ascus” that contains 8 ascospores
- Baker’s yeast (Saccharomyces Cerevisiae) an example of a unicellular ascomycota. Model system for eukaryotic genetic research.
Describe Basidiomycota
- contains most mushrooms, puffballs, and bracket fungi (found on trees)
- They have specialized club-shaped structures called basidia that produce four basidiospores
describe Zygomycota
- include molds, and many soil and decomposer fungi
- After Karyogamy, they produce a specialized reproductive structure called a zygosporangium which grows into a stalked sporangium
what are lichens
- a symbiotic association between a photosynthetic micro-organism (like a cyanobacteria) and a fungus
describe athletes’ foot
Athlete’s foot, a common fungal infection of the feet affects roughly 15% of the global population. A group of fungi called Dermatophytes causes athlete’s foot. Dermatophytes inhabit dead skin and digest keratin, a tough fibrous protein found in the outer layer of skin. Causes itchy, cracking, red, peeling, and blistered skin. Cause by contact with infected skin or dermatophytes. Typically in warm, moist environments. Spending time barefoot in highrisk environments, wearing tight shoes, reusing socks, and not keeping feet dry can increase risk.
describe the Fungal kingdom
Composed of both unicellular eukaryotes and multicellular eukaryotes. Resemble both plants and animals, but closer to animals. Have chitin cell walls. Heterotrophs, and obtain food from external sources. Digest externally by secreting digestive enzymes into the enviroment. Enzymes breakdown dead matter, or living plants or animals, then the fungi absorbs the resulting molecules. They mostly live in terrestrial environments and thrive in damp areas. Though they can be found in extremely hot deserts and aquatic habitats.
what role do fungi play in the environment
They play the role of decomposers in their ecosystems, breaking down organic matter, and helping to recycle nutrients. Saprotrophic fungi utilize non-living organic materials as sources of nutrients and are responsible for the biodegradation or organic materials, such as leaf litter, wood, and other plant debris. They play a vital role in recycling non-living organic materials into essential elements, particularily carbon and nitrogen. Unfortunately, their excellent digestive abilities mean they can contaminate crops and food sources.
what role of fungi play in human life
While fungi can cause disease and agricultural losses, they also play an important role in our diets and daily life. Mushrooms like the Agaricus species, which includes button mushrooms, portobellos, and some truffles, are cultivated and consumed directly. Fungi are also used to make bread, wine, beer, soy sauce, etc. And they are used as pesticides to control plant diseases and pests. They have also led to the production of antibiotics and enzymes used in detergents.
what is the cap of a mushroom
The cap, also known as the pileus, is the expanded, top part of the mushroom. It is thick and fleshy, rounded, and has a generally smooth surface.
what are the gills of a mushroom
The gills, aka Lemellae, are dark ridges located on the underside of the pileus that radiate out from the centre. They are thin, delicate, and nearly black on mature mushrooms
what is the stem of a mushroom
The stem, aka stipe, is attached to the bottom centre of the pileus. Usually white, fleshy, and smooth.
what is the ring of a mushroom
The ring, aka annulus, is joined to the upper end of the stem, just beneath the pileus, in mature mushrooms. The annulus which is delicate and easily rubbed off, is a remnant of a covering enclosing the mushroom early in development.
what are fungi like in the vegetative stage
When in the vegetative stage, fungi are arranged in a network of long, branching filaments called hyphae. In most fungi, the hyphae are divided into cells called septa. The septa are specialized internal cross-walls that have pores that allow the cytoplasm, organelles, and sometimes nuclei to pass through them. The pores allow the fungal cells to communicate with each other. In fungi that lack septa, the entire fungus is essentially one multinuclear cell. Many fungal species have specialized hyphal structures designed for nutrient uptake.
what is apical growth
All hyphae are specialized for growth at their tips, a type of growth called apical growth.
Apical growth produces a mycelium, an interconnected network of hyphae. Mycelia can be underground or it can visible to the naked eye on various surfaces, such as on damp walls and on spoiled food, where they are commonly called mold. Molds can spread rapidly because their thin hyphae grow at their tips to penetrate new food sources.
describe fungal spores
Hyphae initially develop from spores, haploid cells that undergo mitosis to form a haploid multicellular organism. Fungi produce spores as part of both sexual and asexual reproduction. In asexual reproduction, genetically identical spores are produced. In sexual reproduction, the two haploid cells fuse, then the haploid nuclei fuse to form a diploid nucleus, and then meiosis occurs to generate haploid spores.
In either case, the spores disperse and develop into mature fungi
what are fruiting bodies in fungi
Fungi that undergo sexual reproduction produce fruiting bodies for dissemination of sexual spores. Mushrooms are a type of fruiting body, as are truffles.
how are spores different than seeds
Spores are not seeds, they don’t have nutritional supplies, and they must land in a suitable environment that provides nutrients. Fungi are usually low to the ground, so spores are not easily dispersed by the wind. So they’ve evolved different mechanisms like releasing spores into flowing water, attracting insects, or forcibly ejecting spores from the fruiting body.
describe Basidiomycota
Includes many edible mushrooms, including the genus Agaricus.
The basidium is the mushrooms’ microscopic spore-forming structure. Typically, each basidium produces four spores that remain attached until maturity. When they are mature they are forcibly discharged. In Basidiomycota that form fruiting bodies, the gills - the thin ridges on the underside of the mushroom cap - are formed from many basidia.
describe Ascomycota
The largest phylum of Fungi and includes brewer’s and baker’s yeast, Penicillium chrysogenum (the fungus that produces penicillin), and truffles. Characterized by its ascus, a microscopic, sac-like reproductive structure that arises during sexual reproduction. Nonmobile spores are formed within the ascus. Asci can arise singly, like in baker’s yeast, or they can be contained inside a fruiting structure or mushroom, like in truffles and morels. The asci are contained within the mushroom, unlike the basidia of Basidiomycota mushrooms.
During asexual reproduction, conidia, or asexual, nonmotile spores, form on conidiophores, specialized hyphae on which conidia are produced. The swollen tip of the conidiophore is called the vesicle and the phialide is the cell at the end of the conidiophore from which spores are produced.
describe Zygomycota
A former phylum that includes fungi such as black bread mold, and several species used for the industrial production of enzymes, such as lipase. Fungi previously in this phylum are now in either Mucoromycota or Zoopagomycota.
Primarily reproduce Asexually.
Many have hyphae that are tubular, branched, and aseptate.
what are the three types of hyphae in zygomycota
Have a unique structure with three types of Hyphae, each with a different function
- The rhizoids reach below the surface of the substrate on which the fungus is growing to release digestive enzymes and absorb nutrients
- The Sporangiophores are long stalks above the surface that bear clusters of spore-producing sporangia
- The stolons extend horizontally to connect groups of rhizoids and sporangiophores into a fungal network
