1. Chapter 4 Prokaryotic Cell
Functional Anatomy of Prokaryotic and Eukaryotic Cells
Bio 205

2. Prokaryotic Cells Comparing Prokaryotic and Eukaryotic Cells
Prokaryote comes from the Greek words for prenucleus.
Eukaryote comes from the Greek words for true nucleus.

3. Prokaryote Eukaryote Paired chromosomes, in nuclear membrane
One circular chromosome, not in a membrane
No histones
No organelles
Peptidoglycan cell walls
Binary fission
Paired chromosomes, in nuclear membrane
Histones
Organelles
Polysaccharide cell walls
Mitotic spindle

4. Average size: µm  µm
Basic shapes:

5. Most bacteria are monomorphic
Unusual shapes
Star-shaped Stella
Square Haloarcula
Most bacteria are monomorphic
A few are pleomorphic (variable shapes during life cycle)
Figure 4.5

6. Arrangements Pairs: diplococci, diplobacilli Clusters: staphylococci
Chains: streptococci, streptobacilli

7. Glycocalyx Outside cell wall Usually sticky
A capsule is neatly organized
A slime layer is unorganized & loose
Extracellular polysaccharide allows cell to attach
Capsules prevent phagocytosis
Figure 4.6a, b

8. Flagella Outside cell wall Made of chains of flagellin
Attached to a protein hook
Anchored to the wall and membrane by the basal body
Figure 4.8

9. Flagella Arrangement
Figure 4.7

10. Brownian Motion
Flagella motion

11. Motile Cells Rotate flagella to run or tumble
Move toward or away from stimuli (taxis)
Flagella proteins are H antigens (e.g., E. coli O157:H7)

12. Axial Filaments Endoflagella In spirochetes
Anchored at one end of a cell
Rotation causes cell to move
Figure 4.10a

13. Fimbriae Fimbriae allow attachment
Pili are used to transfer DNA from one cell to another
Figure 4.11

14. Cell Wall Prevents osmotic lysis Made of peptidoglycan (in bacteria)
Figure 4.6a, b

15. Peptidoglycan
Polymer of disaccharide N-acetylglucosamine (NAG) & N-acetylmuramic acid (NAM)
Linked by polypeptides
Figure 4.13a

16. Figure 4.13b, c

17. Gram-positive cell walls Gram-negative cell walls
Thin peptidoglycan
No teichoic acids
Outer membrane
Thick peptidoglycan
Teichoic acids
In acid-fast cells, contains mycolic acid

18. Gram-Positive cell walls
Teichoic acids:
Lipoteichoic acid links to plasma membrane
Wall teichoic acid links to peptidoglycan
May regulate movement of cations
Polysaccharides provide antigenic variation
Figure 4.13b

19. Gram-Negative Outer Membrane
Lipopolysaccharides, lipoproteins, phospholipids.
Forms the periplasm between the outer membrane and the plasma membrane.
Protection from phagocytes, complement, antibiotics.
O polysaccharide antigen, e.g., E. coli O157:H7.
Lipid A is an endotoxin.
Porins form channels through membrane

20. Gram Stain Mechanism Crystal violet-iodine crystals form in cell
Gram-positive
Alcohol dehydrates peptidoglycan
CV-I crystals do not leave
Gram-negative
Alcohol dissolves outer membrane and leaves holes in peptidoglycan
CV-I washes out

21. Atypical Cell Walls Mycoplasmas Lack cell walls
Sterols in plasma membrane
Archaea
Wall-less, or
Walls of pseudomurein (lack NAM and D amino acids)

22. Damage to Cell Walls Lysozyme digests disaccharide in peptidoglycan.
Penicillin inhibits peptide bridges in peptidoglycan.
Protoplast is a wall-less cell Gram-positive cell.
Spheroplast is a wall-less Gram-negative cell.
L forms are wall-less cells that swell into irregular shapes.
Protoplasts and spheroplasts are susceptible to osmotic lysis.

23. Plasma Membrane
Figure 4.14a

24. Plasma Membrane Phospholipid bilayer Peripheral proteins
Integral proteins
Transmembrane proteins
Figure 4.14b

25. Fluid Mosaic Model Membrane is as viscous as olive oil.
Proteins move to function
Phospholipids rotate and move laterally
Figure 4.14b