Study your flashcards anywhere!

Download the official Cram app for free >

  • Shuffle
    Toggle On
    Toggle Off
  • Alphabetize
    Toggle On
    Toggle Off
  • Front First
    Toggle On
    Toggle Off
  • Both Sides
    Toggle On
    Toggle Off
  • Read
    Toggle On
    Toggle Off

How to study your flashcards.

Right/Left arrow keys: Navigate between flashcards.right arrow keyleft arrow key

Up/Down arrow keys: Flip the card between the front and back.down keyup key

H key: Show hint (3rd side).h key

A key: Read text to speech.a key


Play button


Play button




Click to flip

18 Cards in this Set

  • Front
  • Back
In what ways do fungi grow?
• multicellular mycelia e.g., mushrooms
• single-celled yeasts
• baker’s yeast, Saccharomyces cerevisiae
• Candida albicans (can be pathogenic in humans)
Multicellular mycelium
• composed of filaments known as hyphae
• Mushrooms consist of densely packed hyphae
• Hyphae
– long narrow tubular filaments optimizes surface area/volume ratio which enhances absorption
– hyphae may be broken into compartments by septa that contain gaps which enables movement of materials between compartments
Extracellular digestion by saprophytic fungi
Fungi secrete digestive enzymes outside of their hyphae:
=> breakdown cellulose, starch, lignin, proteins, & RNA into
=> smaller compounds e.g., sugars, amino acids, nucleic acids
=> able to diffuse across the cell membrane into the hyphae
Lignin and cellulose degrading fungi play important role in global carbon cycle
• Lignin degradation:
– hyphae excrete lignin peroxidase into extracellular environment
- breaks down dense lignin matrix around long strands of cellulose
• Cellulose digestion:
– Cellulases excreted into extracellular environment breakdown cellulose
Concentration of fungal spores are at times comparable to pollen grains in air samples
• Spores fall on food source
- germinate
- mycelium forms
- grows in direction of food
- when food source diminishes, spores are produced
• With adequate food sources mycelia can be large and long-lived
common association between fungi & land plant roots
• fungi make nitrogen and phosphorous available to plants
• fungi receive sugars & other carbon sources from plant
Ectomycorrhizal Fungi (EMF)
Dense network of hyphae around roots
• Found in almost all tree species in temperate & boreal forests
• Basidiomycetes form this type of association
• Short growing season in temperate areas
- slow decomposition
- nitrogen remains tied up in dead tissues
• EMF releases peptidases that cleave peptide bonds of amino acids
Arbuscular mycorrhizal Fungi
(AMF) = Endomycorrhizae
• Grow in cells of root tissue
• Found in 80% of all plant species
• Commonly are Glomeromycetes fungi
• Supply plants with phosphorous
• Especially in grasslands & forest in warm & tropical habitats where the growing season is long and nitrogen is available
• Results from the symbiotic association of a true fungus and either a cyanobacteria or a green alga
• Most fungi are ascomycetes & some are basidiomyctes
• Live in tundras and on bare rock => contribute to rock breakdown and soil formation
• Fungi provides protection to cyanobacteria or green algae
• Algae or cyanobacteria provide carbohydrate to fungus
• On Plants:
– Parasitic fungi killed billions American chestnut & American elm trees (Dutch elm disease)
– Corn smut fungal infection
– Ergot infection (Claviceps pupurea) in rye grains
• On Animals:
– Chytridiomycota species infect & kill frogs
– Cordyceps fungi infects the heads of certain caterpillars
• On Humans:
– Coccidiodomycosis (Valley Fever) causes fungal infection in humans living in the central valley of California
Evolution of Fungi
• Chytridiomycota and Zygomycetes
– branched off very close together in time and are the earliest known fungal groups
• Glomeromycetes
– form endomycorrhizae called arbuscular mycorrhizae
• Basidiomycota and Ascomycota
– represent later, more derived groups
• Only fungi group that are aquatic
• infections in frogs
• motile cells
– gametes in sexual reproduction
– spores in asexual reproduction
• centrioles associated with nuclear membrane during cell division
• Most live in soil
• zygote with tough outer coat
• Some have mutualistic arbuscular mycorrhizal relationships
• Some live on bread e.g., Rhizopus stolonifer
• Hyphae are haploid
Zygomycota Reproduction
• Two different mating types become yoked together
- haploid nuclei fuse
- diploid zygote is resistant to extreme conditions
- favorable conditions enable meiosis
- meiotic products produce haploid cells
- spores are released, germinate, and grow into new mycelia
– All form distinct types of endomycorrhizae called abruscular mycorrhizae
– Tips of hyphae push into plant root cells and branch into treelike structures called arbuscules
Ascomycota (sac fungi)
• Some are microscopic yeast (e.g., Candida albicans)
• Some have sac-like spore producing structures and multicellular mycelia
• Some have dikaryotic stage like Basidiomycota
– Similar reproductive cycle as Basidiomycota except that meiosis takes place in the ascus sac
• club-fungi, club-like spore forming structures
• mushrooms, bracket fungi, & puffballs are reproductive structures
• hyphae from different mating types fuse & mix
their cytoplasms
- cytoplasms of two cells mixed (cytoplasmic fusion)
- each cell produced after initial fusion contains a haploid nucleus from each plant and are called dikaryotic hyphae
dikaryotic hyphae grow into spore-producing bodies (mushrooms, brackets, or puffballs)
- basidia (specialized club-like cells) form on hyphae tips
- two nuclei fuse inside (nuclear fusion) basidia cells to form diploid nucleus
- meiosis
- haploid spore production expelled from end of basidium & dispersed by wind