Sructure of bacteria has two aspects, arrangement and shape.
- So far as the arrangement is concerned, it may Paired (diplo), Grape-like clusters (staphylo) or Chains (strepto).
- In shape they may principally be Rods (bacilli), Spheres (cocci), and Spirals (spirillum).
Bacterial cell shape is determined primarily by a protein called MreB.
- MreB forms a spiral band, a simple cytoskeleton, around the interior of the cell just under the cytoplasmic membrane.
- It is thought to define shape by recruiting additional proteins that then direct the specific pattern of bacterial cell growth.
Bacteria with different shapes present different physical features to the outside world, and these features help cells cope with and adapt to external conditions.