1. Functional Anatomy of Prokaryotic Cells1

2. Prokaryotes Eukaryotes
All living cells can be classified into two groups based on certain structural & functional characteristics
Prokaryotes
Eukaryotes

3. They are chemically similar in the sense that they both contain nucleic acids proteins lipids carbohydrates

4. The distinguishing characteristic of prokaryotes & eukaryotes
Proka. * microm
*DNA is not enclosed within a membrane (singularly arranged chromosome)
*DNA is not associated with histones=special chromosomal proteins found in euk

5. *no membrane-enclosed organelles
*cell wall almost always contain the complex polysaccharide peptidoglycan
*divided by binary fission(DNA is copied & the cell splits into two cells

6. The distinguishing characteristic of prokaryotes & eukaryotes
Euka. *10-100microm.
*DNA is found in cells nucleus which is separated from the cytoplasm by nuclear membrane (DNA is found in multiple chromosomes)
*DNA is associated with histones

7. *the have a number of membrane-enclosed organelles(mitochondria , endoplasmic reticulum Golgi complex lysosomes)
*cell wall is chemically simple
*cell division usually involves mitosis

8. 8

9. PROKARYOTES
EUKARYOTES
BACTERIA
ARCHAEA 9 9

10. BACTERIA

11. Naming and Classifying Microorganisms
The system for nomenclature for microorganisms
The scientific name is binomial
The First is the genus name
The Second is the species name
The first letter of the genus name is always capitilized
Staphylococcus (genus) aureus (species)
Both are underlined or italicized
Staphylococcus aureus

12. Identification of bacteria
Thousands of bacteria species are differentiated by many factors including:
**morphology (shape , size & arrangement) **Chemical composition (staining) **Nutritional requirements **Biochemical activities **Source of energy

13. Morphology Size -- Shape -- & Arrangement Size = 0. 2 – 2
Morphology Size -- Shape -- & Arrangement Size = 0.2 – 2.0 micrometer in diameter micrometer in length Bacterial shapes are determined by heredity

14. Shapes & Arrangements of Bacteria

15. cocci Coccus=spherical =round or oval Diploccoci=pairs
Streptococci=chainlike
Staphylococci=groups (grapelike)

16. Bacilli Bacilli= rode shape mostly Single Diplobacilli=pairs
Streptobacolli=chais
Coccobacilli=oval

17. spiral Have one or more twists----never straight Vibrios=curved rods
Spirilla=helical
Spirochetes=helical & flexible

18. Particular structures
Structure of Bacteria
Essential structures cell wall cell membrane Cytoplasm & nuclear material
Particular structures
capsule
flagella
pili
spore 18

19. Structure of Bacterial cell19 19

20. Structures structures external to the cell wall cell wall itself
structures internal to the cell wall

21. glycocalyx (capsule) flagella axial filaments fimbriae pili
structures external to the cell wall

22. Glycocalyx
Glycocalyx=sugar coat=sub.that surround cells=sticky=external to cell wall
Polysaccharide , polypeptide or both
If attached to cell wall =capsule (well defined) or slim layer(not defined)

23. The degree of which bac. Cause disease
Glycocalyx
Capsule or slime layer
Functions:
Help adherence & attachment
of bacterial cells to surfaces.
Provide nutrients
Protect bacterial cells against dehydration
Increase virulence of bacteria
Protect the pathogenic bacteria.
From phagocytosis by host
WBC .
The degree of which bac. Cause disease 23 23

24. Streptococcus pneumoniae pneumonia respiratory tract

25. FLAGELLA Some bacteria are motile
Locomotory organelles- flagella=long filamentous
appendages
External to cell wall 25 25

26. Flagellar arrangements outside bacterial cell
Atrichous –lack flagella 26

27. Monotrichous – single flagellum at one end
Amphitrichous- flagella at both end of bacterial 27
Lophotrichous-2 or more arising from one end of bacterial cell
Peritrichous – Flagella distributed over the entire
surface, low motility

28. Motility=is the ability of bac
Motility=is the ability of bac. to move itself one direction different directions waves toward a favorable environment or away from an adverse conditions chemotaxis=away from chemicals light=phototaxis

29. Advantages of flagella
Identification of Bacteria
H-antigen = flagellar protein is useful for distinguish variations within species Motility of bacteria

30. Axial filaments spirochetes have unique structure & motility
similar to flagellum
=bundles of fibrils that arise at the end of bacterial cell
**Spiral motion
**Snake-like movement
spirochetes have unique structure & motility 30 30

31. Pili (fimbriae) hair-like projections of the cell
(shorter and thinner than flagella)
Occur at the poles or can evenly distributed on bacterial cell
Fibriae are involve in bacterial attachment to surfaces and resistance to phagocytosis === cause disease
Neisseria gonorrhoeae gonorrhea 31 31

32. Pili bacterial conjugation
Chemical nature is pilin
bacterial conjugation
Sex pili effect the transfer of conjugative plasmids 32

33. Extracellular Appendages
FIMBRIE FLAGELLA
SEX PILI
Extracellular Appendages 33 33

34. Structure of Bacterial cell34 34

35. Composition & structure of cell wall

36. Bacterial cell wall All prokaryotes have cell wall
The cell wall of bacterial cell is
Complex
Surround the fragile plasma membrane (cytoplasmic)
Protect the interior of cell

37. The major functions of cell wall
Prevent bacterial cells from rupturing, when water pressure inside the cell is greater than that outside the cell , so it is essential for bacterial viability Countering the effects of osmotic pressure Providing a rigid platform for surface appendages- flagella, fimbriae, and pili all originate from the wall and extend beyond it

38. Cell wall major functions
Site of action of antibiotics, the most important one
Resistance of Antibiotics
Shape of bacteria

39. Functions of cell wall
The chemical composition of cell wall is used to differentiate major types of bacteria. Be the sites of major antigenic determinants of the cell surface Provide the immunological distinction among bacteria

40. Bacterial cell wall is composed of macromolecular net work = peptidoglycan
Peptidoglycan = peptide + glycan
Peptidoglycan consists of repeating disaccharide attached by polypeptides , that surrounds & protects bacterial cell

41. Disaccharide portion is mad up of Monosaccharides =
N-acetylglucosamine
(NAG)
&
N-acetylmuramic acid=
(NAM)
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Cell Wall 41 41

42. Adjacent rows are linked by polypeptides
Alternating (NAG) &( NAM) molecules are linked in rows to from a carbohydrate backbone (glycan portion )
Adjacent rows are linked by polypeptides
(peptide portion)
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Cell Wall 42 42

43. =bac.cell wall is weakened & the cell undergoes lysis
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Penicillin interferes with final linking of the peptidoglycan rows by peptide
=bac.cell wall is weakened & the cell undergoes lysis
= this destruction caused by rupture of the plasma membrane & the loss of cytoplasm
Cell Wall 43 43

44. Gram positive bacteria cell wall consists of many layers of peptidiglycan forming a thick , rigid structure
Cell wall of Gram positive bac. Contain
Teichoic acids= consist primarily of
an alcohol (glycerol or ribitol)
&
phosphate

45. Wall teichoic acid = linked to the peptidoglycan
Teichoic acid classes
Wall teichoic acid = linked to the peptidoglycan
Lipoteichoic acid= spans the peptidoglycan layer & is linked to the plasma membrane

46. Special components of Gram positive cell wall
Teichoic acid
SPA / M POTEIN 46

47. Teichoic acid =
Regulate the movement of cations (+ve ions) into & out of the cell
Assume in cell growth
Provide wall s antigenic specificity = diagnosis

48. Gram negative bacteria cell wall
Consist of one layer of peptidoglycan
&
an outer membrane
Do not contain teichoic acid
the peptidoglycan is bonded to lipoproteins
(=lipids linked to proteins) in the outer membrane

49. The outer membrane of Gm.-ve bac, consists of
Lipopolysaccharides
lipoproteins
&
phospholipids

50. Lipopolysaccharides Lipid portion Lipid A endotoxin O polysaccharides
antigen
Lipid portion
Lipid A
endotoxin

51. Porin = is a proteins in the outer membrane which is important in the permeability of outer membrane

53. Cell wall structure and Gram stain
GRAM STAIN TECHNIQUE
CELL WALL OF G+VE AND G-VE BACT.
Cell wall structure and Gram stain 53 53

54. Atypical cell walls
1- No or very little cell wall material: Mycoplasma = are the smallest bacteria that can & reproduce outside living cell (sterols in the plasma membranes for protection)
2- Archaea: unusual wall-- No peptidoglycan, , proteins and polysaccharides.
3- Acid-fast cell walls: contain high constration (60%) of Waxy material outside the peptidoglycan. = Mycolic acids prevent uptake of stains. 54 54

55. Damage to the cell wall
Chemicals that damage bact. Cell wall often do not harm the cells of an animal host .Why??
When bacteria are treated with
1) enzymes that are lytic for the cell wall e.g. lysozyme (tears,mucus, saliva)
Active on major cell wall components of most Gram +ve bact.
**back bone disaccharide wall-less cell (protoplast)
When Gram –ve bact. Treated with lysozyme cell wall is not destroyed to the same extant as in Gram +ve bact. Why ?? (outer membrane) (spheroplast) 55

56. Effect of "lysozyme", which is found naturally in tears, mucus, and saliva. -Gram positives are most susceptible and typically they burst (lyse) or, in favorable environments, they may form "protoplasts", which have no cell wall. -Gram negatives are less susceptible and some of the cell wall material remains (spheroplasts)--> Can only survive in favorable conditions as they are weak.

58. Damage to the cell wall
2) antibiotics that interfere with biosynthesis of peptidoglycan, wall-less bacteria are often produced.
antibiotics that damage bact. Cell wall often do not harm the cells of an animal host .Why?? 58

59. Structure of Bacterial cell59 59

60. Structures internal to the cell wall

61. Structures internal to the cell wall
Plasma or cytoplasmic membrane
**Is a thin structure lying inside the cell wall & enclosing the cytoplasm
**consist primarily of phospholipids & proteins

62. Functions of Plasma membrane
Selective permeability = certain molecules & ions pass through the membrane , but others prevented from passing through it
Breakdown of nutrients and the production of energy ( contain enzymes catalyzing the chemical reaction)
Some antibiotics and antibacterial agents kill bacteria by attacking the plasma membrane

63. Damage of plasma membrane
Many antibiotics have effect on plasma membrane
Polymyxins = disrupting phospholipids of the plasma membrane
Alcohols & ammonium compounds = used as disinfectants

64. Structures within the bacterial cell
Cytoplasm: thick aqueous (80% water) semitransparent.
Contains organic molecules and inorganic ions. Proteins(enzymes) , carbohydrates , & lipids
The major structures in the cytoplasm are:
Nucleoid, ribosomes, inclusions 64

65. The major structures in the cytoplasm are:
Nucleoid,= nuclear area containing DNA
Ribosomes
Inclusions = reserve deposits

66. Nuclear material
Plasmids: .
Single, long, double stranded circular DNA=bacterial chromosome.
Carry all the genetic information required for cell structure & function 66 66

67. plasmid extra-chromosomal DNA
Small,circular,doubl-stranded DNA .not connected to bact. Chromosome, replicate independently
May be gained or lost. Without harming bact.
Can be transfer from one bact. To other (biotechnology)
5-100 genes))Cary genes for:
antibiotic resistance,
tolerance to toxic metals,
production of toxins and synthesis of enzymes
Plasmids: . 67 67

68. Nuclear material No nuclear membrane,
absence of nucleoli, hence known as nucleic material or nucleoid,
one to few per bacterium. 68

69. Ribosomes Sites of protein synthesis
Composed of two subunits made of protein and ribosomal RNA.
Prokaryotic ribosomes are 70S while Eukaryotic ribosomes are 80S. 69

70. Erythromycin and chloramphenicol attach to 50 S subunit
Streptomycin and gentamicin attach to 30 S subunit and inhibit protein synthesis.
Bacterial cell can be killed by antibiotic while eukaryotic cell remains unaffected. Why??? 70

71. Inclusions Several kinds of reserve deposits within the cytoplasm
Cells may accumulate certain nutrients when they are plentiful & use them when the environment is deficient
Their number depend on bact. Species == identification

72. Inclusions Reserve deposits Metachromatic granules.
Polysaccharide granules = carbohydrate
Lipid inclusions = lipid storage material
Sulphur granules = energy server
Carboxyzomes = enzymes ** photosynthesis
Gas Vacuoles
Magnetosomes 72

73. Inclusions = Metachromatic granules =large inclusions
some time stain red with blue dye
have diagnostic significance
=stores inorganic phosphate
Corynebacterium diphtheriae

74. Endospores (spores) Resting structures
Clostridium= tetanus – gas gangrene – food poisoning
Bacillus = anthrax
Highly durable dehydrated cells with thick walls & additional layers which formed internal to the bact. cell membrane

75. Endospores when released into environment they survive
-- extreme heat
--lack of water
--exposure to many toxic chemicals & radiation

76. Sporulation = sporogenesis
formation of endospore
(endospre forming bact.)
This occur when nutrient (carbon , nitrogen source ) becomes unavailable or scarce
Germination = formation of vegetative form

77. Endospores (spores) Identification of Bacteria Pathogenesis Resistance77

78. Not a means of reproduction protection
One vegetative cell single endospore
Single endospore one vegetative cell
Not a means of reproduction
protection
Sporulation
germination

79. Endospores are clinically important
Food industry
Resist heating
Freezing
Desiccation
Use of chemicals & radiation
Some bact. Produce toxins

80. BACILLUS ANTHRAX
Bacterial Spores 80 80

81. First Term Exam.
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