1. prevent the osmotic lysis
2. maintain the shape of bacterium
3. causes disease
4. Differentiation between bacteria
4.1. Gram staining
4.1.1. gram (+ve) bacteria appears violet
4.1.2. gram (-ve)bacteria appears pink or ed
5. peptidoglycan (murein)( in bacteria )
5.1. can present alone or with other substances
5.2. Disacchrides attached by polypeptides
5.3. polymer of disacchrides
5.3.1. NAG
5.3.2. NAM
6. Mycoplasms
6.1. Lack cell walls
6.2. Sterols in plasma membrane
7. Damage of cell wall
7.1. Lysozyme
7.1.1. gram (+ve)bacteria as it damage bonds between sugars in backbone
7.1.2. Thoe outer membrane of gram(-ve)bacteria protects it from lysozymes
7.2. EDTA
7.2.1. on gram(-ve)bacteria
8. Gram Positive Bacteria
8.1. Thick peptidoglycan
8.1.1. Linked by polypeptides
8.1.2. NAM and NAG are linked to form backbone
8.1.3. Rows are linked by polypeptides to form cross bridge
8.2. 2-ring basal body
8.3. Disrupted by lysozyme
8.4. Penicillin sensitive
8.5. Teichoic acid
8.5.1. Its -ve charge regulate movement of cations
8.5.2. lipoteichoic acid links to the plasma membrane
8.5.3. Its wall links the peptidoglycan
8.5.4. Provides antigenic specificity
9. Gram Negative Bacteria
9.1. Periplasmic space
9.2. Thin peptidoglycan( susceptible to mechanical breakge)
9.3. Lack the teichoic acids
9.4. 4-ring basal bodies
9.5. Endotoxin (Lipid -A)
9.6. Tetracycline sensitive
9.7. Outer Membrane
9.7.1. lipopolysacchrides
9.7.2. lipoprotein
9.7.3. phospholipids
9.7.4. -ve charge gives protection from phagocytes and complement system
9.7.5. porins: form channels to allow permeability
9.7.6. O-polysacchride antigens
9.7.7. Susceptible to some Beta-Lactam