ABSTRACT
Fungi can be classified into moulds, yeasts, and mushrooms. Most live in terrestrial environments and impact on the decomposition of organic carbon sources such as dead plant or animal matter. They may live as saprophytes or parasites on plants, animals, and even on human beings. Ascomycetes (sac fungi) and Basidiomycetes (mushrooms) are so called ‘Higher Fungi’, while Zygomycetes and Deuteromycetes may also be referred to as Micromycetes. Classification is due mainly to the different life cycles, especially formation of asexual spores or conidia (without the fusion of gametes) and sexual spores. Fungal hyphae germinate from spores or conidia and grow mainly by extension of their terminal cells resulting in mycelia that can be seen without magnification. Spores and conidia are very resistant to extreme conditions and are dispersed throughout the air. Yeasts are unicellular fungi; cell division normally occurs by budding. Under specific conditions, however, they may also show filamentous growth and formation of sexual spores formed within asci (membranous structures in which typically eight ascospores are formed through sexual reproduction of ascomycetes).
