1. Bacterial Morphology Arrangement
1. Bacilli
a.Streptobacilli
b. Bacilli
2. Cocci
a. Cocci
b. Doplococci
c. Streptococci
d. Staphylococci
e. Sarcina ( 3D )
f. Gaffkya ( 2D )

2. Common Shapes & Arrangement

3. Bacterial morphologies (1)

4. Bacterial morphologies (2)

5. Bacterial morphologies (3)

6. Bacterial Morphology Arrangement
3 Spirl
a. Vibrio
b. Spirillum
c. Spirochete

7. Bacterial morphologies (4)

8. Bacterial Cell Structures & Functions

9. Size relationships among prokaryotes

10. Bacterial Cell Structure
Appendages - fdlagella, pili or fimbriae
Surface layers - capsule, cell wall, cell membrane
Cytoplasm - nuclear material, ribosome, mesosome, inclusions etc.
Special structure - endospore

11. Bacterial Cell Structure

12. Appendages 1. flagella e.g. B. megaterium
Some rods and spiral form have this.
a). function: motility
b). origin : cell membrane flagella attach to the cell by hook and basal body which consists of set(s) of rings and rods
Gram - : 2 sets of ring and rods, L, P, S, M rings and rods
e.g. E. coli
Gram + : S, M rings and rods
e.g. B. megaterium

13. Organ of bacterial locomotion

14. Structure of the flagellum

15. Flagella movement(1)

16. Flagella movement(2)

17. Flagella movement(3)

18. b).Origin (continued)
The structure of the bacterial flagella allows it to spin like a propeller and thereby propel the bacterial cell; clockwise or counter clockwise ( Eucaryotic , wave like motion.
Bacterial flagella provides the bacterium with mechanism for swimming toward or away from chemical stimuli, a behavior is knows as CHEMOTAXIX, chemosenors in the cell envelope can detect certain chemicals and signal the flagella to respond.

19. c). position
monotrichous
lophotrichous
peritrichous
d). structure
protein in nature: subunit flagellin

20. 2. Pili or Fimbriae
Shorter than flagella and straighter , smaller. Only on some gram- bacteria.
a). function: adhere. One of the invasive mechanism on bacteria. Some pathogens cause diseases due to this. If mutant (fimbriae) not virulent. Prevent phagocytosis.

21. pili - sex factor. If they make pili, they are + or donors of F factor.
It is necessary for bacterial conjugation resulting in the transfer of DNA from one cell to another.
It have been implicated in the ability of bacteria to recognize specific receptor sites on the host cell membrane. In addition, number of bacteria virus infect only those bacteria have F pilus.

22. b). Origin: Cell membrane
c). Position: common pili , numerous over the cell, usually called fimbriae sex pile, 1-4/cell
d). Structure: composed of proteins which can be dissociated into smaller unit
Pilin . It belongs to a class of protein Lectin which bond to cell surface polysaccharide.

23. II. CELL SURFACE LAYER 1. Capsule or slime layer
Many bacteria are able to secrete material that adheres to the bacterial cell but is actually external to the cell.
It consists of polypeptide and polysaccharide on bacilli. Most of them have only polysaccharide. It is a protective layer that resists host phagocytosis. Medically important.

24. 2. Bacterial Cell Wall
General structure: mucopolysaccharide i.e. peptidoglycan. It is made by N-acetylglucosamine and N-acetylmuramic acid. tetrapeptide ( L-alanine- isoglutamine-lysine-alanine) is attached. The entire cell wall structure is cross linked by covalent bonds. This provide the rigidity necessary to maintain the integrity of the cell.
N-acetylmuramic acid is unique to prokaryotic cell.

25. Cell walls of bacteria(2)

26. Cell walls of bacteria(3)

27. Cell walls of bacteria(4)

28. Cell walls of bacteria(1)

29. Structure of peptidoglycan(1)

30. Structure of peptidoglycan(2)

31. (a). Gram positive bacterial cell wall
Thick peptidoglycan layer
pentaglycin cross linkage.
Teichoic acid: ribitol TA & glycerol TA
Some have peptioglycan teichoic acid.
All have lipoteichoic acid.

32. Function of TA:
* Antigenic determinant
* Participate in the supply of Mg to the cell by binding Mg++
* regulate normal cell division.
For most part, protein is not found as a constituent of the G+ cell wall except M protein on group streptococci

33. Structure of the Gram-positive Cell Wall

34. (b) Gram -
Thin peptidoglycan
Tetrapeptide cross linkage
A second membrane structure: protein and lipopolysaccharide.
Toxicity : endotoxin on lipid A of lipopolysaccharide. glucosamine- glucosamine-long
polysaccharide- repeated sequences of a few sugars (e.g. gal- mann-rham) n= O antigen

35. Structure of peptidoglycan(3)

36. Toxicity : endotoxin on lipid A of lipopolysaccharide.
glucosamine- glucosamine-long
FA FA FA FA
polysaccharide- repeated sequences of a few sugars (e.g. gal- mann-rham) n= O antigen

37. Chemistry of LPS

38. The Gram-negative outer membrane(1)

39. The Gram-negative outer membrane(2)

40. 2. Cell Membrane
Function:
a. control permeability
b. transport e’s and protons for cellular metabolism
c. contain enzymes to synthesis and transport
cell wall substance and for metabolism
d. secret hydrolytic enzymes
e. regulate cell division.
Fluid mosaic model. phospholipid bilayer and protein (structure and enzymatic function). Similar to eukaryotic cell membrane but some differs. e.g. sterols such as cholesterol in Euk not in Prok.

41. The cytoplasmic membrane

42. Functions of the cytoplasmic membrane(1)

43. Functions of the cytoplasmic membrane(2)

44. Transport proteins

45. Classes of membrane transporting systems(1)

46. Classes of membrane transporting systems(2)

47. Classes of membrane transporting systems(3)

48. III. Cytoplasm
80% water, nucleic acids, proteins, carbohydrates, lipid and inorganic ions etc.
1. Bacterial chromosomes
a single large circular double stranded DNA no histone proteins. The only proteins associated with the bacterial chromosomes are the ones for DNA replication, transcription etc.
2. Ribosome
protein synthesis

49. The bacterial chromosome and supercoiling

50. 3. Mesosomes
A large invaginations of the plasma membrane, irregular in shape.
a. increase in membrane surface, which may be useful as a site for enzyme activity in respiration and transport.
b. may participate in cell replication by serving as a place of attachment for the bacterial chromosome.

51. 4. Inclusions Not separate by a membrane but distinct.
Granules of various kinds:
* glycogen,
*polyhydroxybutyric acid droplets (PHB)
i.e. fat droplets
* inorganic metaphosphate (metachromatic granules) - in general, starvation of cell for almost any nutrients leads to the formation of this to serve as an intracellular phosphate reservoir.

52. PHB

53. 5. Chromatophores
Only in photosynthetic bacteria and blue green algae. Prok. no chloroplast, pigment found in lamellae located beneath the cell membrane.

54. IV. Special Structure
* Endospores
Spore former: sporobactobacilli and sporosarcinae - no medical importance. bacillus and clostridium have medical importance.
* Position: median, sub-terminal and terminal have small water, high calcium content and dipicolinic acid (calcium dipicolinate)
extremely resistant to heat, UV, chemicals etc. may be due to many S containing A.A for disulfide groups.

55. The process of endospore formation
After the active growth period approaching the stationary growth phase, a structure called forespore develops within the cells.
It consists of coat, cortex and nuclear structure.

56. Endospores

57.                                                                        
Negatively Stained Bacillus: (A) Vegetative Cell  (B)  Endospore

58. Dipicolinic acid

59. Vegetative/spore-containing cells(1)

60. Vegetative/spore-containing cells(2)

61. Detailed steps in endospore formation(1)

62. Detailed steps in endospore formation(2)

63. Detailed steps in endospore formation(3)