1. Functional Anatomy of Prokaryotic and Eukaryotic Cells
Chapter 4, part A
Functional Anatomy of Prokaryotic and Eukaryotic Cells

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 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 A few are pleomorphic
Unusual shapes
Star-shaped Stella
Square Haloarcula
Most bacteria are monomorphic
A few are pleomorphic
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. Figure 4.8

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. Motile Cells
Figure 4.9

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

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

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

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

17. Figure 4.13b, c

18. Gram-positive cell walls Gram-negative cell walls
Thick peptidoglycan
Teichoic acids
In acid-fast cells, contains mycolic acid
Thin peptidoglycan
No teichoic acids
Outer membrane
LPS
O - polysaccaride
Lipid A

19. 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

20. 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 (proteins) form channels through membrane

21. Gram-Negative Outer Membrane
Figure 4.13c

22. More on cell wall
Is this Gram negative or positive?

23. 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

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

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

26. Plasma Membrane
Figure 4.14a

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

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