Biological Classification Notes

Kingdom Fungi and Viruses: Classification and Characteristics

Kingdom Fungi is classified into Phycomycetes (lower fungi with coenocytic mycelium, e.g., Mucor, Rhizopus, Albugo), Ascomycetes (sac fungi producing ascospores in an ascus, e.g., Aspergillus, Saccharomyces, Neurospora, Morchella), Basidiomycetes (club fungi producing basidiospores on basidia, e.g., Agaricus, Puccinia, Ustilago), and Deuteromycetes (imperfect fungi with no sexual reproduction known, e.g., Alternaria, Colletotrichum, Trichoderma). Each class should be noted with its mycelium type, asexual reproduction method, sexual spore type, and important examples. Viruses are acellular entities covered in this chapter: they consist of a protein coat (capsid) surrounding nucleic acid (DNA or RNA, never both), reproduce only inside living host cells, and are classified by host as bacteriophages (infecting bacteria), plant viruses (mostly RNA, e.g., TMV), and animal viruses (DNA or RNA). Viroids (naked RNA without protein coat, discovered by Diener, cause potato spindle tuber disease) and prions (infectious protein particles causing mad cow disease) complete the acellular infectious agent coverage tested in NEET.