Kingdom: Fungi Characteristics & Structure

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 the 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 dependent 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 increases 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 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 a 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.

William Anderson (Schoolworkhelper Editorial Team)

William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0

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