1. Functional Anatomy of Prokaryotic
Chapter 4
Functional Anatomy of Prokaryotic

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

7. Unusual shapes
Star-shaped Stella
Square Haloarcula
Figure 4.5

9. Sterptococcus pneumoniae
Diplococci
Gram positive
Cause pneumonia disease

10. Staphylococcus aureus
Gram positive
Normal microbiota on skin
aureus = golden colony

11. Streptococcus pyogenes
Gram positive bacteria
Cocci
Cause strep throat , Tonsillitis and Impetigo

12. Bacillus anthracis
Gram positive
Spore forming
Bacilli
Cause Anthrax disease

13. Salmonella typhi
Gram negative
Bacilli
Flagellated
Cause typhoid fever

14. Clostridium botulinum
Gram positive
Bacilli
Spore forming
Cause Food borne botulism

15. Vibrio cholerae
Gram negative
Comma shaped
Flagellated
Cause cholera disease

16. Helicobacter pylori
Gram negative
Helix shaped
Cause gastric ulcer

17. Treponema pallidum
Helically coiled microorganism
Cause syphilis disease

18. Most bacteria are monomorphic
A few are pleomorphic

19. The shape of a bacterium is determined by heredity.
Genetically, most bacteria are monomorphic that is, they maintain a single shape.
However, a number of environmental conditions can alter that shape.

20. If the shape is altered, identification becomes difficult.
Some bacteria, such as Rhizobium and Corynebacterium are genetically pleomorphic, which means they can have many shapes, not just one.

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

22. 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

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

24. Flagella Arrangement
Figure 4.7

25. Figure 4.8

26. 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)

27. Motile Cells
Figure 4.9

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

29. Fimbriae and Pili
Fimbriae allow attachment
Pili are used to transfer DNA from one cell to another

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

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

32. Figure 4.13b, c

33. 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

34. 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

36. 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

37. Gram-Negative Outer Membrane
Figure 4.13c

38. 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

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

40. Damage to Cell Walls Lysozyme digests disaccharide in peptidoglycan.
Penicillin inhibits peptide bridges in peptidoglycan.
Protoplast is a wall-less cell( completely or partially removed).
Spheroplast is a cell from which the cell wall has been almost completely removed.

41. Damage to Cell Walls
L forms or cell wall deficient bacteria (CWD) are wall-less cells that swell into irregular shapes such as Mycoplasma .
Protoplasts and spheroplasts are susceptible to osmotic lysis.

42. Plasma Membrane
Figure 4.14a

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

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

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

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

47. 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.

48. Movement Across Membranes
Figure 4.17

49. 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

50. Figure 4.18c-e

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

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

53. Nuclear Area Nuclear area (nucleoid) One circular chromosome
Figure 4.6a, b

54. Ribosomes
Figure 4.6a

55. Ribosomes
Figure 4.19

56. Ribosomes
Ribosomes are the sites of protein synthesis in bacteria.
Several antibiotics such as streptomycin, neomycin, tetracyclines, and chloramphenicol specifically inhibit protein synthesis by attacking ribosomes.

57. Cytoplasmic inclusions
1- Metachromatic granules
2- Polysaccharide granules
3- Lipid inclusions
4- Sulfur granules
5- Carboxysome
6- Gas vacules
7- Magnetosomes

58. 1- Metachromatic granules
Metachromatic granules = polyphosphate granules= volutin granules
Large granule
Volutin granules + methylene blue  red color
Volutin reserve of inorganic phosphate( ATP , DNA, Phospholipid )
Present in algae, fungi, protozoa and bacteria.
Diagnostic significance of Corynebacterium diphtheria

59. Metachromatic granules

60. Metachromatic granules

61. 2- Polysaccharide granules
Consist of glycogen and starch
Can be demonstrated by iodine when applied to the cells.
Glycogen + iodine  redish brown color
Starch + iodine  blue color
Energy reserves

62. Polysaccharide granules

63. 3- Lipid inclusions
Appear in various species Mycobacterium and Bacillus.
Energy reserves
Polymer of Poly beta hydroxy butyric acid
Polymer of Poly beta hydroxy butyric acid + sudan black stain  red color

64. Lipid inclusions

65. 4- Sulfur granules
Sulfur bacteria that belong to the genus Thiobacillus
Derive energy by oxidizing sulfur and sulfur containing compounds.
These bacteria may deposit sulfur granules in the cell, where they serve as an energy reserve.

66. Sulfur granules

67. 5- Carboxysome
Are inclusions that contain the enzyme Ribulose 1,5-diphosphate carboxylase for CO2 fixation
Bacteria that use carbon dioxide as their sole source of carbon require this enzyme for carbon dioxide fixation during photosynthesis.
Example: cyanobacteria.

68. 6- Gas vacules Hallow cavities found in many aquatic prokaryotes
Maintain buoyancy, so that the cells can remain at the depth in the water appropriate for them to receive sufficient amounts of oxygen, light, and nutrients.

69. 7- Magnetosomes
Inclusions of iron oxide Fe3O4 Formed by several gram negative bacteria such as Aquaspirillum magnetotacticum that act like magnets
Orient magnetotactic bacteria in geomagnetic fields
Destroys H2O2

70. Magnetosomes

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

72. Endospores