fungi Flashcards
(37 cards)
1
Q
Fungi traits
A
- chemoheterotrophic
- sessile
- common ancestor = unicellular flagellated protist
- can be yeast or moulds
2
Q
Fungi phyla
A
- Chytrids
- Zygomycetes
- Glomeromycetes (endomycorrhiza, fungi)
- Ascomycetes (sac fungi)
- Basidiomycetes
3
Q
Fungi as Yeasts
A
- unicellular but can form colonies
- reproduce via binary fission - asexual
- reproduce sexually with spores
- anaerobic and perform fermentation
- prefer most environments
4
Q
Fungi as Moulds
A
- multicellular
- reproduce sexually and asexually via spores (can depend on environment)
- prefer humid environments with organic material
- live indoors, in decaying organic matter, and soil
- produce fuzzy hyphae on surface of organic matter
5
Q
Coenocytic Hyohae
A
aseptate and have continuous cytoplasm with thousands of nuclei
5
Q
Septate Hyphae
A
contain cross-walls that only allow cytoplasm to pass via holes and separate nucleases
6
Q
Mycelia
A
- filamentous structure of many hyphae that increase surface area for enzyme secretion and absorption
- grow in length not width
7
Q
Fungi Reproduction of Spores
A
- produce haploid spores sexually or asexually, and produce hyphae
- spores produce via mitosis AND meiosis, unlike plants (just meiosis)
- spores are resistant to desiccation
- spores represent dispersal
8
Q
Fungi Parasitic Relationships
A
Plant:
- 2nd most important plant pest
- cankers and scabs are necroses caused by fungi digestion of living plant tissue
- cause wilt when hyphae block xylem and leave powdery mildews
Invertebrates:
- attack insects and atachnids
- slow death
- produce spires inside host and when fruiting starts, bursts through host body
Vertebrates:
- Cutaneous - infection occurs on outer layer of the skin due to fungi digesting dead skin and keratin
- hyphae grow in ring-shaped pattern
- localized subcutaneous - infection due to wounds
- systemic - infection widely spread inside host body
9
Q
Fungi Decomposition
A
- break down large complex organic compounds into inorganic forms
- release C and N from dead tissues
- more important than bacteria when it comes to breaking down plant lignin
- speeds nitrogen cycle by releasing CO2 from dead organisms
10
Q
Fungi Mutualism
A
- in cow guts
- farmed by leaf-cutter ants for colony in exchange for leaf mulch
- mycorrhizae
- ectomycorrhizae
- endomychorrhizae
- lichen
11
Q
Mycorrhizae
A
- mycorrhizae: plant roots and fungi exchange carbohydrates from photosynthesis for access to water/minerals (almost all vascular plants have mycorrhizae associates)
12
Q
Ectomycorrhizae
A
- ectomycorrhizae = on surface of root and provides water.minerals - Ascomycota, Basidiomycota, Zygomycota
13
Q
Endomycorrhizae
A
- endomycorrhizae = hyphae penetrates cell root to provide defence against bacteria or herbivores - Glomeromycota
14
Q
Lichen
A
- lichen: the symbiosis between hyphae mycobiont and photosynthetic partner (green algae or cyanobacteria) which receive C and N
- reproduction synchronized for soredia made by thallus (mycobiont around photobiont cell)
- fungus = host, provides place to grow, protection, retains water and minerals
15
Q
Fungi importance to humans
A
- food: cultivate mushrooms
- food making agents: baker’s yeast, soft cheese, hard blue cheese
- antibiotics: Penicillium chrysogenum, metabolic byproduct that kills bacteria
- yeast for vitamins
16
Q
Hallucinogenic toxic fungi
A
- Psilocybe and three related genera contain hallucinogen psilocybin
- magic mushrooms
- pleasant hallucinations in low doses but paranoia when high doses
- Button mushrooms dangerous when eaten raw/large amounts
- contains carcinogens destroyed by cooking
- Amanita highly toxic
- evidence of illness not apparent until liver destruction has begun
- no antidote
17
Q
Heterokaryotic
A
Intermediate stage that precedes the formaiton of dikaryotic cells in fungi
- heterokaryotic cells contain multiple genetically different nuclei within a single cytoplasm
18
Q
Dikaryotic
A
Cells containing two fused nuclei that formed a zygote
19
Q
Plasmogamy
A
Haploid cells from two different mycelia fuse to form heterokaryotic cell with two or more nuclei
20
Q
Kingdom Fungi Phylum Chytridiomycota
A
- mainly freshwater, some in soil, estuaries, on/in animal guts
- aseptate hyphae
- asexual reproduction
- some are decomposers, others are parasitic or commensals
- chytrids implicated in global amphibian decline
21
Q
Kingdom Fungi Phylum Glomeromycota
A
- reduced diversity
- all species are arbuscular endomycorrhizal
- supply minerals, nutrition, water, to plant roots for photosynthesis sugars
- asexual reproduction
21
Q
Kingdom Fungi Phylum Zygomucota
A
- morphologically all very similar
- smaller and less diverse group
- live in soil and organic remains (break down)
- reproduce sexually and asexually via zygospores
- few are parasites, some predators
- predators = produce sticky pads, branches, or rings to trap prey, then prey is penetrated with hyphae and digested from inside
22
Q
Kingdom Fungi Phylum Ascomycota
A
- sac fungi - largest phylum of fungi
- range in size from single-celled yeasts to dist sized truffles
- septate hyphae
- sexual reproduction with spores in sac-like asci (ascospores)
- Some can reproduce asexually - conidia, formed by special hyphae
23
Zygomycota life cycle
1. Hyphae of 2 mating strands (+,-) make contact. Septum forms from behind the hyphal tip, isolating into gametangia
2. Gemetangia duse and plasmogamy takes place
3. Cell walls thicken as dikaryotic zygospore develops
4. Karygomy occurs, nuclei fuse to form diploid nuclei in zygote
5. When germination occurs, zygospore splits open to produce sporangium. Meiosis occurs to make haploid spores
6. New mycelia developed from germinating spores
24
Ascomata life cycle
1. Type of conidia or mycelium fragments serve as gametes
2. Extension of ascogonium fuses with conidium and grows dikaryotic hyphae within developing ascocarp
3. Plasmogamy occurs. Tips of dikaryotic hypha develop into asci.
4. In each ascus, the two nuclei fuse, producing a diploid zygote
5. Meiosis in diploid nucleus produces 4 haploid nuclei
6. 4 nuclei divide by mitosis, then cell walls form around each of the 8 nuclei. These cells are ascospores. Asci developed inside ascocarp, which began to form soon after sexual reproduction began.
7. Asci release their ascospores through an opening in ascocarp
8. When an ascospore germinates, it gives rise to a new mycelium
25
Basidiomycota life cycle
1. basidiospores from 2 compatible fungi germinate and form haploid mycelia
2. plasmogamy occurs and tips of hyphae fuse
3. plasmogamy produces dikaryotic cell that contains two genetically different nuclei
4. dikaryotic cell grows into a mycelium
5. hyphae form a basidiocarp; spore producing cells are under cap on gills
6. karyogamy occurs and nuclei fuse to make zygote
7. zygote undergoes meiosis to make 4 haploid nuclei
8. 4 basidiospores form and are released
25
Kingdom Fungi Phylum Basidiomycota
- parasites, decomposers, predators, typical mushrooms
- septate hyphae
- sexual structures of classic mushroom and toadstools:
basidium = spore pedestal; within the basidiocarp for producing and releasing basidiospores
Basiciocarp = fruiting body
- important decomposers - lignin
- cap contains gills
- gills lined with basidia
26
Fungi Dispersal Agents
- Airborn
- Waterborn (humid environments)
- vectors: animals carry spores
- explosives: some mushrooms build up pressure causing rapid expansion of gill tissues, thus, ejecting spores
27
Anamalia Common ancestor
- common ancestor = choanoflagellates
- heterotrophic protists, with a single flagellum surrounded by microvilli
- cell morphology similar to sponges
- cell morphology unique to animal cells
- DNA sequence homology
28
Animal Characteristics
- multicellular
- lack cell walls
- bodies held together with extracellular matrix - structural proteins such as collagen
- tissues - groups of cells with common structure/function
- nervous tissue and muscle tissue unique to animals
- chemoheterotrophic
- sexual reproduction - diploid dominant
- motile at lease one in life cycle
29
True tissues
separated by a membranous layer
30
Innovations in animal evolution
1. embryonic development
2. unique tissue development
3. body symmetry
4. presence or absence of body cavity
5. presence of a unique group of hox genes
31
Cleavage
Diploid zygote undergoes a number of mitotic cell division - leads to hollow blastula
32
Gastrulation
blastula forms gastrula with different layers of embryonic tissues
- germ layers give rise to tissues and organs
33
Origin of embryonic tissue layers and muscles
- Porifera: have cell-to-cell and cell-to ECM adhesion, but they do not form complex tissues
- Eumetazoa: form complex tissues and are divided into two groups based on number of germ layers - diploblastic or tripoblastic
34
Germ layers
endo = digestive tract
ecto = outer covering (skin and nerves)
meso = muscle and other organs (only tripoblastic)
