Fungi: distinctive features, structure, and growth

Armillaria ostoyae

A large fungus in Oregon that spreads across about 2,200 acres and is over 2,000 years old.

Chitin

A nitrogen-containing structural polysaccharide in fungal cell walls.

Substrate

The array of organic compounds fungi use as food.

Osmotrophy

Feeding by absorbing small organic molecules from the environment.

Heterotrophy

Obtaining food from the environment rather than producing it independently.

Absorptive nutrition

Secreting enzymes onto food, digesting it externally, and absorbing the resulting small molecules.

Glycogen

A carbohydrate used for sugar storage in fungi and animals.

Mycelium

The body of most fungi, composed of a network of hyphae.

Hyphae

Microscopic, branched filaments that make up most fungal bodies.

Aseptate hyphae

Hyphae without cross walls; may contain many nuclei in a continuous cytoplasm.

Multinucleate hyphae

Hyphae containing multiple nuclei.

Septa

Cross walls that subdivide fungal hyphae into cells, often with pores.

Fruiting body

A reproductive structure made of densely packed hyphae that produces spores.

Spores (fungi)

Reproductive cells with protective cell walls that disperse and can grow into new mycelia.

Hyphal tip growth

Fungal growth in which the hypha extends at its tip through water uptake and delivery of cell-wall materials.

Cytoplasmic streaming

Movement of cytoplasm that helps distribute materials within a fungal hypha.

Osmosis

Movement of water across a selectively permeable membrane toward the region with higher solute concentration.

Golgi apparatus

Cell structure that modifies and packages materials into vesicles.

Vesicles

Small membrane-bound sacs that transport enzymes and cell-wall materials to the hyphal tip.