 (1) Respiration  (2) Nutrition  (3) Amount of peptidoglycan  (4) Shape and arrangement Classified and Identified by:

A) AEROBIC BACTERIA  This bacteria must have oxygen to survive

B) ANAEROBIC BACTERIA  This bacteria will grow and live in the absence of Oxygen

C) FACULATIVE BACTERIA  Organisms that can grow in either environment  With or without O 2  ex. E coli

 Bacterium that lives in the digestive tract of humans  CAUSED by contact with feces (stool) of humans and animals. Drinking and/or eating contaminated foods  SYMPTOMS include bloody diarrhea, stomach cramps, nausea

A) AUTOTROPHIC BACTERIA  Make their own food from inorganic substances

B) HETEROTROPHIC BACTERIA  Obtain food from other organisms *Biochemical reactions are used to identify a certain strain of bacteria by looking at what type of sugars they consume

 The cell walls of different bacteria contain varying amounts of a chemical called PEPTIDOGLYCAN  *History* In 1844 Danish physician Hans Gram developed a chemical test called Gram Staining in order to determine if the cell wall of a bacterium contains more or less peptidoglycan  Gram staining divides bacteria into 2 groups…

1. GRAM-POSITIVE BACTERIA  After adding purple dye to the bacteria – bacteria remains purple because the dye sticks to large amounts of peptidiglycan in the cell walls of the bacteria  Ex. Of diseases…  Entercoccus  Listeria  Streptococcus

2. GRAM-NEGATIVE BACTERIA  After adding purple dye to the bacteria – bacteria turns pinkish- red  B/c dye cannot stick to the small amounts of peptidiglycan in cell walls  Ex. Of diseases…  E. Coli  Gonorrhea  Salmonella  Meningitis

 Bacteria occur mainly in 5 different shapes