Fungi Flashcards
What is Fungi?
Diverse/widespread group
Breakdown organic matter and recycle vital nutrients
Fungi are:
Multicellular heterotrophic eukaryotes
Lack an internal digestive system (absorb nutrients from outside)
What are the 2 problems presented by the mode of digestion of fungi?
- Cannot access large molecules
SOLUTION: enzymes to breakdown large molecules(external digestion) - Cannot move to search for food
SOLUTION: growth of fungal body to find nutrients
Hyphae is?
Highly branched filaments
Cell walls of fungi are made of?
Chitin (complex carbohydrate)
Hyphae grows at…
Tips to all fungal movement
Hyphae form extensive network called?
Mycelium
What is crucial in hyphae to transport material into cell across cell wall/membrane
Cytoplasmic continuity
Earliest fungi lacked what to separate cells?
Later groups gained what to divide hyphae into filaments of connected cells
Coenocytic
Septal
List the 3 different nutrient types of fungi
- Decomposes (=saprotrophs): feed on dead matter
- Parasites: infect living tissues of plants/animals
- Mutualists: symbiotic interaction (with plants, animals, cyanobacteria)
Breakdown cellulose and lignin
Perform essential recycling of chemical elements
Do not need us but we need them
WHAT AM I?
Decomposers
About 30% of fungi are this
Attack food drops and are toxic
Ex. Corn smut
WHAT AM I?
Parasite (or pathogen) Fungi
Mutualistic relationship with other organisms
Have profound ecological effects
Examples:
-fungus-plants (mycorrhizae/endosymbionts)
-fungus-animal (leaf-cutter ants)
-fungus-microbe (lichens-cyanobacteria/algae)
WHAT AM I?
Mutualists (or Symbionts)
Lichens
Consist mostly of fungal hyphae
Mutualistic relationship with photosynthetic micro organisms (cyanobacteria, algae)
Photosynthetic algae cells form thin layer just under surface of lichen
List 1 of the problems and its solution for the reproduction of fungi
- Finding mates (genetic diversity)–fungi reproduce by spores that are very prolific
- Dispersal–spores can be produced asexually or sexually
Name the 3 steps of sexual reproduction of fungi
- Plasmogamy: fusion of cytoplasm of 2 haploid cells
- Karyogamy: nuclear fusion (forms diploid stage)
- Meiosis
Nuclei in hyphae of mycelium are usually…
Haploid
The diploid stage:
- short lived
- Undergoes meiosis
- produces haploid spores that form haploid hyphae which then form haploid mycelium
Only fungi with motile flagellated spores (zoospores)
Asexual reproduction only
Primarily aquatic
Act as decomposers, parasites or mutualists
WHAT AM I?
Chytrids
Have aspetate or coenocytic hyphae (no cross walls)
Sexual reproduction (+ and - mating types)
-terminal haploid gametangia fuse forming diploid zygosporangium that undergoes meiosis to produced haploid spores, then released from stalked sporangium for asexual reproduction
WHAT AM I?
Zygomycetes (loss of flagellated spores)
Includes about half the fungi in soil
Asexual reproduction (walling off sections of hyphae)
Form symbiotic associations with plant roots (mycorrhizae)
Ecological importance
WHAT AM I?
Glomeromycetes
Dikarya
Separate monophyletic group of fungi
Distinguished by presence of septa between cells
Can control number of nuclei per cell
Produce dikaryotic cells through growth
Known as sac fungi
Most diverse group
In asexual reproduction, haploid asexual spores (=conidia) are produced in conidiophores
In sexual reproduction produces ascospores (haploid) in ascus in the sexual structure (ascocarp)
WHAT AM I?
Ascomycetes
Known as club fungi
No asexual reproduction
Sexual reproduction seen through production of club-shaped basidia developing on basidiocarp that carry sexual spores on surface (=basidiospores)
Include mushrooms, puffballs, shelf fungi, mutualists, plant parasites
WHAT AM I?
Basidiomycetes
