Bacterial shapes and sizes

Size

Average bacillus is 1 μm in diameter by 4 μm in length. They range in size from less than 0.5 to 1.0 μm in diameter to 10 to 20 μm in length for some of the spirilla. For perspective 1,000,000 bacterium placed end-to-end could measure ~ 2 inches.

Shape (3 or 4 main bacterial forms)

1. Spherical or ovoid (•cocci)

•   Coccus(single cells)

•   Diplococci(in pairs)

•   Staphylococci(clusters)

•   Streptococci(chains)

•   Sarcinae(cubical groups)

•   Tetrad (Group of 4)

2. Rod-shaped (_bacilli)

•   Coccobacilli (more oval)

•    Bacillus (single cells)

•    Pallisades

•    Streptobacilli (forming a chain)

•   Diplobacilli (in pairs)

3. Spiral (spirochaete)

•   Spirilla (rigid)

•   Spirochetes (flexible)

4. Comma (৲ vibro)

•    Vibrios(curved, comma).

5.Other