Mycology

  • Myco- = fungus
  • -ology= study of

General Characteristics of Fungi:

  • Eukaryotic
  • Decomposers – the best recyclers around
  • No chlorophyll – non photosynthetic
  • Most multicellular (hyphae) – some unicellular (yeast)
  • Non-motile
  • Cell walls made of chitin (kite-in) instead of cellulose like that of a plant
  • Are more related to animals than plant kingdom
  • Lack true roots, leaves and stems
  • Absorptive heterotrophs -Digest food externally and then absorb it
  • Lack of chlorophyll affects the lifestyle of fungi
  • Not dependant on light
  • Can occupy dark habitats
  • Can grow in any direction
  • Can invade the interior of
  • a substrate with
  • absorptive filaments

Structures

  • Body of fungus made of tiny filaments or tubes called hyphae .
  • Contain cytoplasm and nuclei (more than 1)
  • Each hyphae is one continuous cell
  • Cell wall made of chitin
  • A tangled mess of hyphae is called mycelium
  • Rhizoids are root-like parts of fungi that anchor them to the substrate (whatever they are bonding to)
  • Mycelium increase the surface area of the fungi to absorb more nutrients.

CLASSIFICATION OF FUNGI:

  • Fungi can be classified into 5 groups
  • Fungi evolved from an aquatic, flagellated ancestor
  • Chytrids
  • Glomeromycetes (Mycorrhizae fungi)
  • Mycorrhizae are mutually beneficial associations of plant roots and fungi

o    Common and may have enabled plants to colonize land

o    Help create an extending network for the plant to absorb more nutrients and water

  • Ascomycetes (Sac fungi)

o    Truffles and yeast

  • Basidiomycetes (club fungi)

o    Puff ball mushroom

  • Zygomycetes (zygote fungi)

Fungus Reproduction:

  • Fungi produce spores in both asexual and sexual life cycles
  • Mushrooms let out spores from their pores that are carried by the wind to meet other spores and become a new fungi
  • Yeast are unicellular and divide into new fungal cells (mitosis)

o    In some fungi, fusion of haploid hypha produces a heterokaryotic stage containing nuclei from two parents (fusion of cytoplasm)

o    After the nuclei fuse, meiosis produces haploid spores (can grow in fungi and are the asexual part of the life cycle)

General Fungi Reproduction Cycles:

  • But fungal groups do differ in their life cycles and reproductive structures

Reproduction in Basidiomycetes:

  • Basidiomycota (typical mushroom)
  • ASCOMYCOTA
  • FUNGI NUTRITION:
  • Fungi absorb food after digesting it outside their bodies

o    Fungi are heterotrophic eukaryotes

FUNGI NUTRITION:

  • Fungi use digestive enzymes to break down their food then absorb the liquid. (acquire nutrients such as nitrogen)
  • Examples:
    • trap nematodes (little worms who feed on fungi) and paralyze them with special juices then absorbs and digests the nitrogen out of them.

3 Modes of Nutrition
in Fungi:

  • Saprophytes
  • Parasites
  • Mutualists (symbionts)

Saprophytes

  • Use non-living organic material
  • Important scavengers in ecosystems
  • Important in recycling carbon, nitrogen and essential mineral nutrients

Parasites

  • Use organic material from living organisms, harming them in some way
  • Range of hosts from single-celled diatoms to fungi, to plants to animals to humans
  • Mutualists (symbionts)
  • Fungi that have a mutually beneficial relationship with other living organisms
  • Mycorrhizae – beneficial relationship with fungi with plant root

o    More than 90% of plants in nature have a mycorrhizal in roots (example: Truffles- expensive delicacy!)

  • Lichens – associations of fungi with algae or cyanobacteria

o    Food source for animals, breaking down rocks into soil

  • Parasitic fungi harm plants and animals

o    Parasitic fungi cause 80% of plant diseases

o    Can kill plants and affect crops

  • Many fungi are harmful to humans
  • Can cause human diseases – allergies, athletes foot, ringworm, yeast infection

Ringworm

  • A contagious fungal infection having characteristic red ring that can appear on an infected person’s skin
  • Can affect the scalp, the body (particularly the groin), the feet, and the nails
  • Also called Tinea

Benefits of Fungi

  • Fungi also form mutualistic relationships with animals
  • Some animals benefit from the digestive abilities of lichens
  • Lichens consist of fungi living mutually with photosynthetic organisms

o    Lichens consist of algae or cyanobacteria (protists or bacteria) within a fungal network

  • Fungi have enormous ecological, economic and practical uses

o    Ecological= fungi are essential decomposers; mycorrhizae increase plant growth

o    Economic/Practical= antibiotics and food (making bleu cheese/ truffles and truffle hunting)

  • More Useful Fungi:
  • Yeasts – baking and brewing beer
  • Antibiotics – penicillin & cephalosporin
  • Production of organic acids – citric acid in Coke
  • Steroids and medicines – birth control pills

MAJOR PARTS OF A MUSHROOM:

  • Cap (Pileus) – The top part of the mushroom.
  • Cup (Volva) – A cup-shaped structure at the base of the mushroom. The basal cup is the remnant of the button (the rounded, undeveloped mushroom before the fruiting body appears). Not all mushrooms have a cup.
  • Gills (Lamellae) – A series of radially arranged (from the center) flat surfaces located on the underside of the cap. Spores are made in the gills.
  • Mycelial threads – Root-like filaments that anchor the mushroom in the soil.
  • Ring (Annulus) – A skirt-like ring of tissue circling the stem of mature mushrooms. Not all mushrooms have a ring.
  • Scales – Rough patches of tissue on the surface of the cap
  • Stem (Stape) – The main support of the mushroom; it is topped by the cap. Not all mushrooms have a stem.

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3 Comments on "Kingdom: Fungi Characteristics & Structure"

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Shubham
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The best! I like this theory!

arvind
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please add stractural classification of fungai(asco,deutero and zygomycotina

cat
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Thanks!

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