1. Introduction to bacteria

2. Key features of a bacteria

3. Identifying bacteria Size, shape, color Culturing techniques
Metabolic attributes
DNA

4. Gram stain Usually the first test done to identify bacteria
The Gram's stain differentiates between two major cell wall types.
Gram positive and Gram negative

5. Gram positive
Gram positive bacteria have walls containing relatively large amounts of peptidoglycan = a starch
Staphylococcus epidermidis, Streptococcus pyogenes, Clostridium tetani, Bacillus anthacis (ANTHRAX)

6. Gram negative
Gram negative species have walls containing small amounts of peptidoglycan and a lipopolysaccharide = a fat/sugar combo
Escherichia coli, Salmonella typhi, Vibrio cholerae and Bordetella
Gram negative bacteria are harder to control with antibiotics

7. Exceptions Not all bacteria can be stained by Gram's method
the best-known exceptions belong to the genus Mycobacterium which have waxy cell wall.
These include Mycobacterium tuberculosis (TB) and Mycobacterium leprae (leprosy).

8. Gram stain has four steps: 1. crystal violet, the primary stain 2
Gram stain has four steps: 1. crystal violet, the primary stain 2. iodine, which acts as a mordant by forming a crystal violet-iodine complex 3. alcohol, which decolorizes 4. safranin, the counterstain. G+ organisms are purple (or bluish), G- organisms are red.

9. How does it work?

10. Cell envelope of Gram positive

11. Cell envelope of Gram negative

12. Summary Know how bacteria are different than eukaryotic cells
Know key features of bacteria
Know a key difference between Gram + and Gram - bacteria
Know how the gram stain works and how we use it