Biological classification

• Bacteria are the sole members of the Kingdom Monera
• Bacteria are grouped based on their shape: Coccus, Bacillus, Vibrio, and Spirillum
• Archaebacteria live in extreme habitats and have a different cell wall structure
• Eubacteria are characterised by a rigid cell wall and may be motile with a flagellum
• Protista includes all single-celled eukaryotes
• Chrysophytes include diatoms and golden algae, found in fresh water and marine environments
• Dinoflagellates are mostly marine and photosynthetic, with stiff cellulose plates on the outer surface
• Euglenoids are fresh water organisms with a protein-rich layer called pellicle instead of a cell wall
• Slime Moulds are saprophytic protists that form fruiting bodies bearing spores under suitable conditions
• Protozoans are heterotrophs and live as predators or parasites
• Fungi are heterotrophic organisms with a great diversity in morphology and habitat
• Fungi can be seen on moist bread, rotten fruits, and are used to make bread, beer, and antibiotics
• Fungi are filamentous and their bodies consist of long, slender thread-like structures called hyphae
• The network of hyphae is known as mycelium
• Some hyphae are continuous tubes filled with multinucleated cytoplasm, known as coenocytic hyphae
• Fungi cell walls are composed of chitin and polysaccharides
• Most fungi are heterotrophic and absorb soluble organic matter from dead substrates, known as saprophytes
• Fungi that depend on living plants and animals are called parasites
• Fungi can also live in association with algae as lichens and with roots of higher plants as mycorrhiza
• Reproduction in fungi can occur by vegetative means such as fragmentation, fission, and budding
• Asexual reproduction in fungi is by spores called conidia, sporangiospores, or zoospores
• Sexual reproduction in fungi is by oospores, ascospores, and basidiospores
• Various spores in fungi are produced in distinct structures called fruiting bodies
• The sexual cycle in fungi involves fusion of protoplasms, fusion of nuclei, and meiosis resulting in haploid spores
• In some fungi, a dikaryotic stage occurs before cells become diploid, known as dikaryon and dikaryophase
• Phycomycetes are found in aquatic habitats, on decaying wood, or as obligate parasites on plants
• Ascomycetes are commonly known as sac-fungi and reproduce asexually by conidia and sexually by ascospores
• Basidiomycetes include mushrooms, bracket fungi, and puffballs, and reproduce sexually by basidiospores
• Deuteromycetes are imperfect fungi that reproduce only by asexual spores known as conidia
• Viruses, viroids, prions, and lichens are not included in the five kingdom system of classification
• Viroids are smaller infectious agents that lack a protein coat and consist of free RNA
• Prions are infectious neurological diseases transmitted by abnormally folded proteins
• Lichens are symbiotic associations between algae and fungi, where algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients