1. Prokaryotic Cells Morphology Specialized Structures Ultrastructure

2. Prokaryotic Cell l Size, Shape & Arrangement –0.2 µm to 2.0 µm diameter –2 µm to 8 µm in length –Three basic shapes »cocci (spheres) »bacillus (rods) »spirochete (twisted/spiral) –Pleomorphic shapes

3. Prokaryotic Cells l Characteristics –Smaller than eukaryotic cells –No nuclei or chromosomes –No membrane-bound internal organelles –Circular genomic DNA –70S Ribosomes –Cell division by binary fission –No meiosis; recombination by transfer of DNA fragments

4. Prokaryotic Cell l Cocci –spheres –Staphylo- clusters –Strepto- chains

5. Prokaryotic Cell l Bacilli –rods

6. Prokaryotic Cell l Spirochete –spirals

7. Prokaryotic Cells l Specialized Structures –Endospores – a structure produce primarily by Clostridia and Bacillus species to resist desication –Acid Fast Bacteria – a waxy sheet or coat produced by Mycobacteria –Club shape – produced by Corneybacteria

8. Prokaryotic Cells l Flagella l Capsules l Cell envelope l Fimbriae l Pili

9. Prokaryotic Cells

10. l Flagella –Long filamentous protein »filament »hook »basal body –Rotates to propel cell –Taxis (positive and negative)

11. Prokaryotic Cells l Capsules –Slime layer –Polysaccharide or polypeptide –Protection from phagocytosis by host –“Stickiness” permits adherence –Prevents desication

12. Prokaryotic Cells l Cell Envelope or Cell Wall –Gram positive »Peptidoglycan (Multi layer) »Teichoic acid –Gram negative »Peptidoglycan (single layer) »Outer membrane (lipopolysaccharide) –Primary function is resist changes in osmotic pressure; also functions in recognition

13. Prokaryotic Cells l Peptidoglycan –N-acetylglucosamine –N-acetylmuramic acid –Peptide composed of D- and L- amino acids

14. Prokaryotic Cells

15. l Lipopolysaccharide –Outer membrane of Gram negative cells –Composed of lipid and carbohydrate –Carbohydrate referred to as O- antigen –Associated with some endotoxins in pathogenic G- bacteria

16. Prokaryotic Cells

17. l Teichoic Acid –sugar alcohol plus phosphate

18. Prokaryotic Cells l Fimbriae –associated with the adhesiveness of cells to surfaces

19. Prokaryotic Cells l Pili –involved in the transfer of genetic material

20. Prokaryotic Cells l Internal Structures –Generally no internal structures –Some bacteria produce polyalkonate granules when carbon is in surplus and nitrogen is limiting