Fungi

Fungi

Fungi are plant-like organisms that lack chlorophyll. Fungi are one of the five kingdoms of life. Many fungi are good and useful while some cause problems. Fungi (kingdom Fungi) are heterotrophs. They cannot manufacture their own food as photosynthetic organisms can. Fungi are the principle decomposers in every ecosystem. They can break down most organic compounds including lignin, a compound that is a major component of wood and is very difficult to break down or digest. Yeasts are single-celled, but most fungal species are multicellular.  Multicellular fungi are composed of filaments called hyphae (singular: hypha). Fungi have cell walls (like plants) but the cell walls are composed of chitin, Most fungi do not have flagella in any phase of their life cycle. They move toward food by growing toward it.

 the life cycle involves the fusion of hyphae from two individuals, forming a mycelium that contains haploid nuclei of both individuals. The fusion of hyphae is called plasmogamy. The fused hyphae containing haploid nuclei from two individuals is heterokaryotic. In some cases, plasmogamy results in cells with one nucleus from each individual. This condition is called dikaryotic. Eventually, two nuclei that originated from different individuals fuse to form a diploid zygote. Meiosis then produces either four haploid nuclei or four haploid cells.

The diagram below shows the generalized life cycle of fungi.

Spores are reproductive cells that are dispersed by wind. They are capable of germinating and producing a new mycelium.

Yeast

Yeast are single-celled members of the sac fungi.

Most reproduction is asexual; a small cell pinches off from a larger cell. This type of mitosis where a smaller and a larger cell are produced is called budding.

Yeast are important in leavening bread by CO₂ production and in producing ethanol for alcoholic beverages.

 Club Fungi

As mushrum is a multicellular fungi, Asexual reproduction is rare, The fruiting bodies are called basidiocarps. This is the visible "mushroom".

Basidiospores germinate to produce monokaryotic (haploid, one nucleus per cell) hyphae. Mushrooms are composed of dikaryotic hyphae which are formed when hyphae fuse. Dikaryotic nuclei within the basidium fuse to produce a zygote and meiosis then produces basidiospores.
references
http://en.wikipedia.org/