Viruses, Bacteria, and Fungi

    I.   Viruses
            A. Non-living
            B. Particles of nucleic acids enclosed in a protective protein coat
            C. Linear or circular dsDNA, ssDNA, dsRNA, or ssRNA  (note: ds = double stranded; ss = single stranded)
            D. Obligate intracellular parasites
            E. Various human viruses and plant viruses

    II. Viroids and Prions are even simpler in structure than viruses

    **Pay particular attention to the mode of reproduction in each Kingdom below and in the next 4 lectures**

    III. Review: Types of reproduction
            A. Asexual or vegetative reproduction
            B. Sexual reproduction
                    1. Alternation of generations = a life cycle that alternates between a haploid (1n), gamete producing generation called the gametophyte and a diploid (2n), spore producing generation called the
                        sporophyte:

IV. Kingdom Monera: (Prokaryotes)
        A. Unicellular; no organelles; haploid (1n) only
        B. Cell wall made of peptidoglycan (a carbohydrate/protein polymer)
        C. Circular dsDNA
        D. Reproduction is asexual by binary fission
        E. Classification: two main branches of prokaryotes
            1. Bacteria (includes cyanobacteria)
            2. Archaea
        F. Prokaryotic cell shapes: coccus, bacillus, and spirillum
        G. Significance to humans
            1. beneficial bacteria: N2 fixation (Rhizobium), decomposers, intestinal E. coli
            2. pathogenic bacteria
            3. Controlling bacteria
                    a) chemicals: nonspecific disinfectants and specific antibiotics
                    b) low or high temperatures
                    c) low oxygen
            4. Commercial uses of bacteria

V. Kingdom Fungi (Eukaryotes)
        A. Fungal characteristics
            1. multicellular (except unicellular yeasts )
            2. Absorptive nutrition: heterotrophs
            3. Decompose dead organic material (their most important ecological function)
            4. Cell wall made of chitin (a polysacharide)
            5. Hyphae and Mycelium
            6. Reproduce by releasing spores, sexually or asexually (requires a water or very moist environment)
        B. Fungi in the natural environment
            1. Three main types:  Saprophytic, Parasitic, and Mutualistic
            2. Beneficial fungi
                    a) Saprophytic and mutualistic types
                    b) Antibiotic-penicillin (1928)
                    c) Cyclosporin 1979
            3. Pathogenic fungi
                    a) Plant diseases
                        (1) Locally (in you back yard)
                        (2) Epidemics: 1840’s: Late blight of potato; 1930’s USA: Dutch elm disease; Chestnut blight
                    b) Human diseases
                        (1) Mycotoxins:
                                    -corn or peanuts contaminated with aflatoxins, which are toxic chemicals secreted by a fungus.
                                    -Ergot of rye and other grain crops contaminated with toxic hallucinogenic compounds (like LSD) secreted by a fungus
        C. Beverages and foods from Fungi
            1. Yeast
            2. Edible fungi – mushrooms, morels, truffles, kombucha