1. Functional Anatomy of Prokaryotic and Eukaryotic Cells
Chapter 4
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. Flagella arrangement flash animation

11. Figure 4.8

12. Flagella structure flash animation

13. 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)

14. Motile Cells
Figure 4.9

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

16. Motility flash animation

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

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

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

20. Figure 4.13b, c

21. 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

22. 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

23. 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

24. Gram-Negative Outer Membrane
Figure 4.13c

25. 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

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

27. 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.

28. Plasma Membrane
Figure 4.14a

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

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

31. Plasma Membrane
Selective permeability allows passage of some molecules
Enzymes for ATP production
Photosynthetic pigments on foldings called chromatophores or thylakoids

32. Plasma Membrane
Damage to the membrane by alcohols, quaternary ammonium (detergents) and polymyxin antibiotics causes leakage of cell contents.

33. Movement Across Membranes
Simple diffusion: Movement of a solute from an area of high concentration to an area of low concentration.
Facilitative diffusion: Solute combines with a transporter protein in the membrane.

34. Movement Across Membranes
Figure 4.17

35. Movement Across Membranes
Osmosis
Movement of water across a selectively permeable membrane from an area of high water concentration to an area of lower water.
Osmotic pressure
The pressure needed to stop the movement of water across the membrane.
Figure 4.18a

36. Figure 4.18c-e

37. Movement Across Membranes
Active transport of substances requires a transporter protein and ATP.
Group translocation of substances requires a transporter protein and PEP.

38. Cytoplasm Cytoplasm is the substance inside the plasma membrane
Figure 4.6a, b

39. Nuclear Area
Nuclear area (nucleoid)
Figure 4.6a, b

40. Ribosomes
Figure 4.6a

41. Ribosomes
Figure 4.19

42. Inclusions Metachromatic granules (volutin) Phosphate reserves
Polysaccharide granules
Lipid inclusions
Sulfur granules
Carboxysomes
Gas vacuoles
Magnetosomes
Phosphate reserves
Energy reserves
Ribulose 1,5-diphosphate carboxylase for CO2 fixation
Protein covered cylinders
Iron oxide (destroys H2O2)

43. Endospores Resting cells Resistant to desiccation, heat, chemicals
Bacillus, Clostridium
Sporulation: Endospore formation
Germination: Return to vegetative state

44. Figure 4.21a

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

46. Figure 4.22a

47. Flagella and Cilia
Figure 4.23a, b

48. Microtubules
Tubulin
9 pairs + 2 arrangements
Figure 4.23c

49. Cell Wall Cell wall Plants, algae, fungi Carbohydrates
Cellulose, chitin, glucan, mannan
Glycocalyx
Carbohydrates extending from animal plasma membrane
Bonded to proteins and lipids in membrane

50. Plasma Membrane Phospholipid bilayer Peripheral proteins
Integral proteins
Transmembrane proteins
Sterols
Glycocalyx carbohydrates

51. Plasma Membrane
Selective permeability allows passage of some molecules
Simple diffusion
Facilitative diffusion
Osmosis
Active transport
Endocytosis
Phagocytosis: Pseudopods extend and engulf particles
Pinocytosis: Membrane folds inward bringing in fluid and dissolved substances

52. Eukaryotic Cell
Cytoplasm Substance inside plasma membrane and outside nucleus
Cytosol Fluid portion of cytoplasm
Cytoskeleton Microfilaments, intermediate filaments, microtubules
Cytoplasmic streaming Movement of cytoplasm throughout cells

53. Organelles Membrane-bound: Nucleus Contains chromosomes
ER Transport network
Golgi complex Membrane formation and secretion
Lysosome Digestive enzymes
Vacuole Brings food into cells and provides support
Mitochondrion Cellular respiration
Chloroplast Photosynthesis
Peroxisome Oxidation of fatty acids; destroys H2O2

54. Eukaryotic Cell Not membrane-bound: Ribosome Protein synthesis
Centrosome Consists of protein fibers and centrioles
Centriole Mitotic spindle formation

55. Nucleus
Figure 4.24

56. Endoplasmic Reticulum
Figure 4.25

57. Ribosomes 80S Membrane-bound Attached to ER Free In cytoplasm 70S
In chloroplasts and mitochondria

58. Golgi Complex
Figure 4.26

59. Lysosomes
Figure 4.22b

60. Vacuoles
Figure 4.22b

61. Mitochondrion
Figure 4.27

62. Chloroplast
Figure 4.28

63. Endosymbiotic Theory
Figure 10.2