1. BACTERIAL
MORHOLOGY

2. Eukaryote Prokaryote Nucleus No Nucleus Paired chromosomes
Organelles
Polysaccharide cell walls
Mitotic spindle
No Nucleus
One circular chromosome
No organelles
Peptidoglycan cell walls
Binary fission

3. Are unicellular and most multiply by binary fission Basic shapes:
Average size: µm  µm
Are unicellular and most multiply by binary fission
Basic shapes:
COCCUS BACILLUS SPIRAL

4. Arrangements Pairs: Clusters: Staphylococci
Diplococci, Diplobacilli
Clusters: Staphylococci
Chains: Streptococci, Streptobacilli

5. Arrangements of cocci:
Determined by division of planes.

6. Arrangements of bacilli:
Determined by division of planes.

7. Arrangements of Spiral bacteria

8. Double-stranded helix formed by Bacillus subtilis.

9. Bacterial structure
Prokaryote cell

10. Glycocalyx Outside cell wall Usually sticky
Capsule: Prevent phagocytosis
A slime layer is unorganized & loose glycocalyx
Extracellular polysaccharide (EPS) allows cell to attach
Figure 4.6a, b

11. Flagella Long filamentous appendages Outside cell wall
Made of chains of flagellin
Attached to a protein hook
Anchored to the wall and membrane by the basal body

12. Four arrangements of flagella:
Flagella Arrangement
Four arrangements of flagella:

13. Fimbriae and Pili
Short, thin appendages
Attachment

14. Cell Wall Prevents osmotic lysis Made of peptidoglycan
Contributes to disease capability and site of action of some antibiotics.

15. Peptidoglycan
Polymer of disaccharide: N-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM)
Linked by polypeptides
Small arrows: Where penicillin interferes with linkage of peptidoglycan rows

16. Gram positive vs. gram negative cell walls

17. Gram-positive cell walls Gram-negative cell walls
Thick peptidoglycan
Teichoic acids (alcohol+phosphate)
In acid-fast cells, contains mycolic acid (waxy lipid): Allows them to be grouped into medically significant types.
Thin peptidoglycan
No teichoic acids
Outer membrane:
Prevent phagocytosis
Barrier to certain antibiotics

18. Gram-Positive cell walls
Teichoic acids:
Lipoteichoic acid links to plasma membrane
Wall teichoic acid links to peptidoglycan
May regulate movement of cations (+ charge)
Polysaccharides provide antigenic variation (Identification)

19. Gram-Negative Outer Membrane
Lipopolysaccharides, lipoproteins, phospholipids.
Forms the periplasm between the outer membrane and the plasma membrane.
Protection from phagocytes, antibiotics, and complement (30+ liver proteins that protect host).
O polysaccharide antigen, e.g., E. coli O157:H7.
Lipid A is an endotoxin.
Porins (proteins) form channels through membrane to pass other molecules

20. Gram-Negative Outer Membrane

23. Damage to Cell Walls
Lysozyme digests disaccharide in peptidoglycan (Gram+ve cell walls: Destroyed, Gram-ve cell wall: Damaged).
Penicillin inhibits peptide bridges in peptidoglycan.

24. Plasma Membrane

26. Plasma Membrane: Fluid Mosaic Model
Selectively permeable
Phospholipid bilayer
Peripheral proteins
Integral proteins
Transmembrane proteins
Figure 4.14b

27. Fluid Mosaic Model Membrane is as viscous as olive oil.
Proteins: Movable
Phospholipids: Movable

28. Plasma Membrane
Carry enzymes for metabolic reactions: nutrient breakdown, energy production, photosynthesis
Selective permeability allows passage of some molecules
Enzymes for ATP production
Photosynthetic pigments on foldings called thylakoids
Damage to the membrane by detergents, and polymyxin antibiotics causes leakage of cell contents.