Fungi

How do fungi acquire nutrients?

Fungi are heterotrophs-they cannot make their own food. They digest their food while it is still in the environment by secreting powerful hydrolyric enzymes, called exoenzymes, into their surroundings. Exoenzymes break down complex molecules to smaller organic compounds that the fungi can absorb into their bodies and use.

Because of this mode of nutrition, fungi have evolved what structure to provide for both extensive surface are and rapid growth?

Fungal hyphae form an interwoven mass called a mycelium (plural, mycelia) that surrounds and infiltrates the material on which the gungus feeds. The structure of a mycelium maximizes the ratio of its surface are to its volume, making feeding more efficient. A fungal mycelium grows rapidly, as proteins and other materials synthesized by the fungus are channeled through cytoplasmic streaming to the tips of the extending hyphae,

How do the cell walls of fungi differ from the cell walls of plants?

Unlike the cellulose walls of plants, fungal cell walls contain chitin, a strong but flexible nitrogen-containing polysaccharide.

How do fungi contribute to an ecosystem?

Fungi are primarily responsible for keeping ecosystems stocked with the inorganic nutrients essential for plant growth. Without these decomposers, many elements would become tied up in organic matter. Plants and the animals that eat them could not exist because elements taken from the soil would not be returned. Fungi also form symbiotic relationships with plants, algae, cyanobacteria, and animals. All of these relationships have profound ecological effects.

Give some examples of how fungi are important to humans.

We depend on their ecological services as decomposers and recyclers of organic matter. Without mycorrhizae, our agriculture would be far less productive. Mushrooms are a popular food, but they are not the only fungi we eat. Humans have used yeasts to produce alcoholic beverages and raise bread for thousands of years. Many fungi have great medical value as well. Fungi also figure prominently in research in molecular biology and biotechnology. Genetically modified fungi hold much promise.

Hypha (plural, hyphae)

A filament that collectively makes up the body of a fungus.

Mycelium

The densely branched network of hyphae in a fungus.

Chitin

A structural polysaccharide of an amino sugar found in many fungi and in the exoskeletons of all arthropods.

Ingestion

A heterotrophic mode of nutrition in which other organisms or detritus are eaten whole or in pieces.

What type of symbiotic relationship does mycorhizae have with plant roots? Explain

A Mutually beneficial relationship. Mycorrhzal fungi (fungi that form mycorrhizae) can deliver phosphate ions and other minerals to plants, which the plants themselves cannot acquire on their own. In exchange, the plants supply the fungi with organic nutrients.

What key feature separates each phyla of fungi from the common ancestors line?

Chytrids are unique among fungi in having flagellated spores, called zoospores. Zygomycetes have horizontal hyphae that spread out over a food source, penetrate it, and absorb nutrients. Glomeromycetes all form a distinct type of endomycorrhizae called arbuscular mycorrhizae. The defining feature of ascomcetes is the production of sexual spores in saclike asci (singular, ascus); thus, they are commonly called sac fungi. Basidiomycetes derive their name from the basidium (Latin for "little pedestal"), a cell in which a transient diploid stage occurs during the fungal life cycle.

Lichen

The symbiotic collective formed by the mutualistic association between a fungus and a photsynthetic alga or cyanobacterium.