Fungi......

Tina Wed Dec 10, 2008 11:24 am

Fungi(By: Tina) lol!

What are fungi?
Ans: Fungi is the kingdom, they are heterotrophic organism, possessing chitinous cell walls.Some of the fungi are unicellular, some are multi-cellular.
Cell Structure
Ans: Fungi grow as hyphae, which extend at their tips. This apical growth form is in contrast with other filamentous organisms, like filamentous green algae, which grow by repeated cell divisions within a chain of cells. Some fungi grow as single-celled yeasts which reproduce by budding, and some dimorphic fungi can switch between a yeast phase and a hyphal phase in response to environmental conditions. Fungal hyphae may have several nuclei within each hyphal compartment, and many budding yeasts are diploid.
Obtaining Food (Nutrition)
Ans: Growth of fungi as hyphae on or in solid substrates or single cells in aquatic environments is adapted to efficient extraction of nutrients from these environments, because these growth forms have high surface area to volume ratios. These adaptations in morphology are complemented by hydrolytic enzymes secreted into the environment for digestion of large organic molecules, such as polysaccharides, proteins, lipids, and other organic substrates into smaller molecules.These molecules are then absorbed as nutrients into the fungal cells.
Traditionally, the fungi are considered heterotrophs, organisms that rely solely on carbon fixed by other organisms for metabolism. Fungi have evolved a remarkable metabolic versatility that allows many of them to use a large variety of organic substrates for growth, including simple compounds as nitrate, ammonia, acetate, or ethanol.Recent research raises the possibility that some fungi utilize the pigment melanin to extract energy from ionizing radiation, such as gamma radiation for "radiotrophic" growth.It has been proposed that this process might bear some similarity to photosynthesis in plants,but detailed biochemical data supporting the existence of this hypothetical pathway are presently lacking.
Reproduction
Ans: Reproduction of fungi is complex, reflecting the heterogeneity in lifestyles and genetic make up within this group of organisms.Many fungi reproduce either sexually or asexually, depending on conditions in the environment. These conditions trigger genetically determined developmental programs leading to the expression of specialized structures for sexual or asexual reproduction. These structures aid both reproduction and efficient dissemination of spores or spore-containing propagules.
Major types
Ans:
Ascomycota is a Division/Phylum of Fungi, and subkingdom Dikarya, whose members are commonly known as the Sac Fungi. They are the largest phylum of the kingdom Fungi, with over 30,000 species. Characteristically, when reproducing sexually, they produce nonmotile spores in a distinctive type of microscopic cell called an "ascus". These spores are called ascospores. However, some members of the Ascomycota do not reproduce sexually and do not form asci or ascospores.
Basidiomycota is one of two large phyla that, together with the Ascomycota, comprise the subkingdom Dikarya, which were in general what were called the "Higher Fungi" within the Kingdom Fungi. More specifically the Basidiomycota include mushrooms, puffballs, stinkhorns, bracket fungi, other polypores, jelly fungi, boletes, chanterelles, earth stars, smuts, bunts, rusts, mirror yeasts, and the human pathogenic yeast.