**Most bacteria are 0.2 um in diameter

and 2-8 um in length.

**Bacteria of medical importance

•0.2 – 1.5 µm in diameter

•3 – 5 µm in length

www.shurgard.co.uk

S. pneumoniaeLactobacillus sp Fusobacterium

polymorphum

*Cocci that remain in pairs after dividing are called diplococci.*Cocci that remain in chains after dividing are called streptococci.*Cocci that divide in two planes and remain in groups of four are called tetrads.*Cocci that divide in three planes and remain in groups cube like groups of eight are called sarcinae.*Cocci that divide in multiple planes and form grape like clusters or sheets are called staphylococci.

**Since bacilli only divide across their short axis there are fewer groupings.

•Most bacilli appear as single rods. Diplobacilli appear in pairs after division.

•Streptobacilli appear in chains after division.

• Some bacilli are so short and fat that they look like cocci and are referred to as coccobacilli.

Stella are star-shaped.Haloarcula, a genus of halophilic

archaea, are rectangular.

1. http://classes.midlandstech.edu/carterp/courses/bio225/chap04/lecture2.htm

2. http://examples.yourdictionary.com/examples-of-bacteria.html3. faculty.ccbcmd.edu/courses/bio141/lecguide/unit1/shape/shape.h

tml4. science.kennesaw.edu/~jhendrix/ahmicro/shapes.pdf5. study.com/.../bacterial-cell-morphology-and-classification-

definition