Most bacteria appear in variations of three major shapes when viewed under the light microscope:
Structure of bacteria has two aspects, arrangement and shape. As for the arrangemen, it may be Paired (diplo), Grape-like clusters (staphylo) or Chains (strepto).
In shape they may principally be Rods (bacilli), Spheres (cocci), and Spirals (spirillum).
Examples include;
E. coli
Mycoplasma gallicepticum
Epulosiscium fishelsoni