1.  Prokaryotic cells all lack a nucleus and other internal cell membranes.  Both bacteria and cyanobacteria are prokaryotic.

2.  Bacteria come in three basic shapes:

coccus,   bacillus, and spirillum.

3.  Almost all eubacteria are heterotrophs and obtain nutrition from outside sources.  Many of these bacteria are saphrophytic and live by causing decay and putrification of organic material.  Some eubacteria are parasitic and responsible for disease in plant, animals, and humans.

4.  The cyanobacteria are autotrophs and obtain nutrition through photosynthesis.  They possess chlorophyll a and other pigments but lack plastids. (Remember, they are prokaryotic).  These organisms are sometimes responsible for algal blooms in polluted lakes.