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biodiversity of microorganisms, characteristics of life, viruses that…

- - - - small (20nm-450nm in diameter), simple in compositition
      - consist of central nucleic acid surrounded by protein capsule
      - infect plant, animals and bacterial cells
      - contain RNA or DNA never both
      - some like HIV enclosed by a sheath of lipids and protein molecules, originates from host cells outer membrane
      - acellular don't have a nucleus, cytoplasm or organelle
      - shape vary from rod-shaped, spherical to more complex
    - - parasites only respond within living cells and known as obligate intracellular parasites
      - host specific, some tissue specific eg. poliovirus only infect cells of nerve tissue
      - are pathogens and cause diseases in plants and animals/humans, tabacco mosaic virus (TMV) is a plant virus. Humans viruses, AIDS, flu, measles
      - reproduce by converting genetic material (DNA or RNA) of host cell into viral nucleic acids so new viruses produced
  - - - are unicellular occur as single cells, filaments and colonies
      - surrounded by a cell wall that consists of polysaccharides (carbohydrates), proteins, and lipids
      - disease causing bacteria the cell wall surrounded by a slime layer that protects cell from desiccation and enemies (immune cells)
      - plasma membrane that encloses cytoplasm is below cell wall
      - cytoplasm has no membrane bound organelles like vacuoles, plastids, mitochondria and ER but they ribosomes do occur.
      - true nucleus membrane bound is absent
      - genetic material (DNA) concentrated in chromatin network known as nucleoid
      - bacteria moves in lungs by means of a long, thread-like structure called flagella (flagellum)
    - - rod shaped (bacillus)
      - spherical shaped (coccus)
      - spiral shaped (spirillum)
      - comma shaped (vibro)
    - - unicellular and simple
      - have no true nucleus and are prokaryotic
      - some are autotrophic, produce own organic substances by photosynthesis and chemosynthesis
      - majority heterotrophic cannot produce own organic substances
      - three types of heterotrophic
        
        parasitic bacteria - obtain food from living organisms
        
        saprophytic bacteria - obtain food from dead organic matter
        
        mutualistic - obtain food from symbiotic relationship with another organism, both benefit
  - - - protozoa
        
        animal like, unicellular, heterotrophic organisms
        
        examples: microscopic, unicellular amoeba, paramecium
      - algae
        
        plant like, uni or multi cellular, auto trophic organisms
        
        examples macroscopic, multicellular red, brown and green algae; microscopic, unicellular diatoms,
    - - uni or multicellular
      - algae photosynthesis they have chloroplasts in cells
      - various locomotion's occur , eg. pseudopodia (amoeba); cillia (paramecium)
      - protozoa (animal like protists) ingest food by phagocytosis
      - cell wall composition varies in plant-like protists; green algae have cell walls of cellulose while diatoms have cell wall of silica that give organism shiny appearance
    - - all have true nuclei and are eukaryotic
      - some are unicellular and microscopically small, others simple multicellular organism, shows primitive level of cell differentiation or specialization
      - algae are autotrophic and can produce own nutrients, other protists into two cells with identical genetic material, some do reproduce sexually
      - protists live in almost any environment where water occurs as most protists are aquatic
  - - - macroscopic fungi
        
        fleshy fungi with visible fruiting bodies known as mushroom
      - microscopic fungi
        
        unicellular yeasts
        
        multicellular thread like moulds where some parts seen with naked eye, other part micrscopic
      - basic structure
        
        structure of Rhizopus
        
        multicellular and consist of a mass of branched filaments or hyphae
        
        hyphae interwoven to form vegetative body, known as mycelium
        
        has a thallus, no true roots, stems and leaves can be distuinguished
        
        types
        
        runners/ stolons
        
        hyphae branch horizontally on surface of substrate
        
        rhizoids
        
        branches of stolon that penetrate substrate and anchor mycelium
        
        sporangiophore
        
        hyphae that grow up and vertically and develop sporangia on tips to produce spores
        
        hyphae branched and no cross walls (asepate)
        
        hypha contains cytoplasm and large number of nuclei. hyphae is known as coenocyte
    - - yeast unicellular, mushrooms and moulds multicellular
      - all fungi have true nuclei and are eukaryotic
      - funngi have cell wall consisting of chitin
      - fungi consist of a mass of branched filaments or hyphae
      - fungi have no chlorophyll and are heterotrophic
        
        most are saprophytic and live off dead organic plant and animal matter, eg. bread moulds and mushrooms
        
        some are parasites and feed off living material, eg. fungus that causes athletes foot
        
        some mutualistically with other organisms where both organisms benefit
      - reproduction
        
        unicellular fungi
        
        asexually by binary dusion
        
        multicellular fungi
        
        asexually by means of spores during favorable conditions
        
        sexually by means of gametes during unfavorable conditions