Cyanobacteria Final Review

  1. Structure
    - kingdom
    - organelles
    - Svedburg
    - Membranes
    - Cytoplasm
    - Storage molecule

    Lack a nucleus: have a naked DNA that does not associate with proteins 

    • Only organelles are ribosomes (70S)
    • Have internal membranes (parallel to one another) called thylakoids through which photosynthesis occurs-         

    • Phycobilisomes are on the surface-          
    • (phycoerythrin on the outermost, then phycocyanin, and on the inside, allophycocyanin) 

    Cytoplasm appears granular due to starch acting as a storage molecule and acts like glycogen; also contains aspartic acid 

    Contain gas vacuoles
  2. Mobility
    • No flagella or cilia-          
    • If they demonstrate movement, its due to extrusion of mucilage or currents-         
    • One form demonstrates swimming (synechococcus)
    • Gliding, sliding, twisting motion
  3. Location
    • Mostly in freshwater 
    • Some marine and moist environments, like moist soil 
    • Some are epiphytes, attached to something 
    • Extreme environments
  4. Importance
    • They are important as plankton at the base of the food chain
    • Symbiosis:
    • Can grow with fungi and have a unique structure
  5. Pigments
    • Phycobilins
    • Chlorophyll a
    • Carotenoids
  6. Cell Wall
    • -          NAM and NAG arranged in crosslinks attached to glycine molecules
    • -          Made of peptidoglycan
    • -          Looks like one big cellulose molecule
  7. Cells
    • Cells:
    • -          Filamentous: dominant (true and false branching)
    • -          Unicellular: not many
    • -          Colonial: not many’
    • -          Gelatinous sheath around made of carbs and water, slimy, and allows binding together (prevents dehydration); the cells of cyanobacteria are joined only by their walls or sheaths, so that each cell leads an independent life
    • Contain heterocysts and akinetes 
  8. Reproduction
    • No sexual reproduction, but instead asexual reproduction through binary fission 
    • Reproduction through exospores- same as binary fission, but different sizes 
    • Reproduction through fragmentation: break off and form new structures 
    • Reproduction through hormogonia: a part of the filament that separates and grows apart from the original filament
  9. Human Relevances
    • Forms stromatolites by binding with calcium-rich sediments
    • Form plankton at the surface of the water
    • Cause blooms when they can’t regulate their gas vesicles properlyà secrete toxins
    •  fix nitrogen; cause water blooms, thus resulting in a depletion of oxygen and, therefore fish kills
    • Blooms also cause the water to smell and taste weird; it clogs intake filters due to the gelatinous matrix

    Symbiosis with Azolla helps rice growth Food source:

    • spirulina -Enhances plumage color and luster in birds
    • Potential source of antibiotic and anticancer compounds- 
    • Lyngbya: anti-leukemia activity
    • Phormidium- anti-hep B
    • Exposure to toxins during dialysis can kill
    • May cause human dermatitis (Lynbgya) 

    production of endotoxins
Card Set
Cyanobacteria Final Review