1. The Structure of Bacteria

2. I. Prokaryotic Cells A. Differentiated by: 1. Morphology – Shape
a. Most bacteria are monomorphic (maintain a single shape)
2. Chemical composition – staining methods
3. Nutritional needs
4. Biochemical activities
5. Source of energy

3. II. Basic Shapes
Bacillus (plural: bacilli)
1. rod-like

4. Coccus (plural: cocci)
1. spherical

5. C. Spiral: have more than one twist
1. vibrio: comma shaped
2. spirillum (plural: spirilla): rigid – wavy

6. spirochete: a. corkscrew shaped
b. flexible

8. D. Other Shapes 1. irregular/spindle 2. square shaped: Red Sea 1981
3. triangular shaped: 1986
4. star shaped: Stella

9. III. Size Prokaryotes among the smallest organisms
Most range: µm to 2.0 µm diameter µm to 8 µm in length RBC ~7.5 µm diameter

10. 3. Large Surface Area : Volume Ratio
a. no internal part of cell is far from surface
b. nutrients to all parts of cell

11. IV. Common Cell Arrangements
Cell Division
1. Binary fission (see handout)
2. some cells divide w/o separating
3. can divide in more than one plane

12. B. One Plane:
Single
Diplo:
Pairs
Diplococcus/Diplobacillus

13. Strepto:
Chains
Streptococcus/Streptobacillus

14. C. Two Planes
1. Tetrad
a) four cells in a cube
b) spherical

15. D. Three Planes E. Random Sarcinae: Eight cells in a cube
1. staphlo: grapelike clusters
2. staphlococcus

16. F. Additional 1. Bacilli divide in one plane a) end-to-end
b) side-by-side
2. Spiral typically do not group together