1. Prokaryotic Cell Structure

2. Bacterial Envelope comprises the inner cell membrane and the cell wall
if present, may have an outer membrane such as in gram-negative bacteria
May also be comprised of a capsule

3. Capsule or Slime Layer
Made of polysaccharides (dextran, levan, cellulose)
Outer part of cell envelope
Not easily washed off (slime)
Indicates virulence of organism
Cannot be stained (must stain background)
Helps them attach to other surfaces
Prevents phagocytosis

4. Capsules Not all organism have capsules (nonencapsulated)
On agar, encapsulated is smooth, glistening, and mucoid
On agar, non-encapsulated is dry and rough
Variation on capsule is glycocalyx

5. Cell Wall
Gram Positive- thicker than gram negative because of peptidoglycan with amino acid bridges (NAG and NAM) to make interconnected mesh-like molecule; also has teichoic acids
Gram Negative- peptidoglycan layer (inner wall) covered with lipoproteins

6. Cytoplasmic Membrane
The bacterial cytoplasmic membrane is a fluid phospholipid bilayer that encloses the bacterial cytoplasm.
Inward folding are called mesosomes- part of electron transport system; especially present during cell division
Mesosomes not found in gram-negative bacteria

7. Nucleoid and Pasmids DNA not bounded by nuclear membrane
Bacteria chromosome made from single strand DNA
Coiled around RNA core
Plasmids are found in some bacteria
Considered extrachromosomal DNA
Can transfer genetic information in process called conjugation

8. Flagella Threadlike extensions Four groups Monotrichous- single plar
Amphitrichous- both ends
Lophotrichous- tuft of flagella
Peritrichous-flagella over entire surface area
Made of protein flagellin
Made of a hook and basal body
Bacteria spins one way and flagella spins the other way

9. Flagellum

10. Pili (Fimbriae)
Pili (hair) and fimbriae (fringe) are shorter and thinner than flagella
Hair-like all over cell
Fimbriae are like velcro so they can stick to things and help form biofilm
Pili are a bit longer and help to transfer genetic material through conjugation over the pilus bridge

11. Pili and Conjugation

12. Endospore May lie dry and dormant for a while
Germinate when conditions are right
Sporogenesis when conditions are poor for bacteria
Can be stained and seen with microscope