Fungi are eukaryotes that belong to kingdom Fungi. While many fungi are multi-cellular, some are also single-celled, such as yeast. Fungi are divided into many phyla, but the three most common are zygomycota, basidiomycota, and ascomycota. Fungi are usually classified based on structure and method of sexual reproduction. All fungi, however, are heterotrophic, deriving and absorbing their organic compounds from the environment around them. Fungi are key members of any habitat.
Fungi (singular, fungus): Kingdom in the domain Eukarya that includes molds, mushrooms, and yeasts.
Chitin: A polysaccharide found only in the cell walls of fungi.
Hyphae (singular, hypha): The filaments of multicellular fungi.
Mycelium (plural, mycelia): The body of a fungus comprised of a mass of hyphae.
Asexual Spores: Many multi-cellular fungi reproduce asexually by producing haploid spores by mitosis.
Budding: Type of asexual reproduction in yeasts in which an offspring cell pinches off from the parent cell.
Zygospore: Diploid spore in fungi that is produced by the fusion of two haploid parent cells.
Mycorrhiza: The symbiotic relationship formed between a fungus and a plant.
Lichen: The symbiotic association between a fungus and a photosynthetic organism.
Fungi can reproduce both asexually and sexually. They spend most of their life cycle as haploid. Diploid cells only form during sexual reproduction.
Asexual reproduction allows fungi to spread quickly.
Sexual reproduction increases genetic variation.
Parasitic fungi can cause illness and eventual death.
Fungi can also form mutualistic relationship.
A common use of fungi in our society is as a source of food. For example, we eat many types of mushroom, the fruiting body of a fungus, and we use yeast to bake bread.
Fungi also play an important role in medicine, producing chemicals and antibiotics, such as penicillin, that have revolutionized treatment of human diseases and infections.
In the world at large, fungi, which are heterotrophs, serve as important decomposers in the environment, breaking down dead organic material from which they also derive nutrients. Fungi thus release important molecules back into the ecosystem.
However, fungi can also be harmful, causing certain diseases when they infect human tissue. Fungus is at the root of such diseases as athlete’s foot and ringworm.