This document discusses the morphology, structure, and identification of bacteria. It begins by describing the various shapes bacteria can take, such as rod-shaped, spherical, and spiral. It then details the internal structures of bacterial cells, including the cytoplasm, ribosomes, nucleoid, plasma membrane, cell wall, and flagella. Gram staining is introduced as an important method for initially classifying bacteria as either Gram-positive or Gram-negative based on differences in cell wall structure. The document provides diagrams and explanations of key bacterial cellular components.

1. BACTERIOLOGI
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2. Bacteria on Earth
Bacteria are in every environment imaginable!
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3. Size
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Fig. 2-5 Six Comparisons Among Various Living Things and Molecules 3
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4. Rod-Shaped Bacteria

5. Spherical Bacteria

6. Spirochete:
Borrelia burgdorferi
Spiral-Shaped Bacteria

7. Bacterial Morphology
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8. Bacterial Anatomy (Overview)
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9. Prokaryotic Cells
• Means “before a nucleus”
• Domains Bacteria and Archaea
• Can live in environmental extremes
• Live off diverse energy sources
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http://micro.magnet.fsu.edu/cells/bacteriacell.html http://www.daviddarling.info/encyclopedia/P/prokaryoticcell.h

10. Prokaryotic
Structures
• Cytoplasm
– A liquid material that
particles are suspended in
• Ribosomes
– Site of protein synthesis
– Located in cytoplasm
• Nucleoid
– Contains hereditary
material (DNA) of the
cell
– Located in cytoplasm
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11. Prokaryotic
•
Structures
Plasma membrane
– Encloses the cell
– Regulates material into
and out of cell
• Cell Wall
– Supports cell and
determines its shape
• Capsule
– Slime layer
– Protects
– Helps to not dry out
– Helps attach to other
cells
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12. Prokaryotic
Structures
• Flagella
– Used to swim/move
– Spins like a propeller
or whip like
• Pilli
– Hair or threadlike
structures
– Help stick to other
cells for mating or
animal cells for food
and protection
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13. Cytoplasm
• Composed largely of water, together with proteins, nucleic
acid, lipids and small amount of sugars and salts
• R ib os om e s : numerous, 15-20nm in diameter with 70S;
distributed throughout the cytoplasm; sensitive to
streptomycin and erythromycin site of protein synthesis
 P las m id s : extrachromosomal
genetic elements
 Inclu s ions : sources of stored
energy, e,g volutin

14. Plasmid Plasmids
are
small ， circular/line ， extrachromosomal ， do
uble-stranded DNA molecules 。
capable of self-replication and contain genes
that confer some properties such as antibiotic
resistance ， virulence.
Inclusions Inclusions of
 are aggregates of
various compounds
Bacteria
that are normally
g ra nulo s involved in storing
energy reserves or
e building blocks for
the cell.
 accumilate when a
cell is grown in the
presence of excess
nutrients

15. Cell
membrane
• Site of biosynthesis of DNA, cell wall polymers and
membrane lipids. Selective permeability and transport of
solutes into cells
• Electron transport and oxidative phosphorylation
• Excretion of hydrolytic exoenzymes

16. Nucleus
• Lacking nuclear
membrane, absence
of nucleoli, hence
known as nucleic
material or nucleoid,
one to several per
bacterium.

17. Prokaryotic Cell Structure
 Glycocalyx - term to describe
substances that surround bacterial
cells
 1. Capsule
 if substance is organized and firmly
attached to cell wall
 2. Slime Layer
 if substance is unorganized and loosely
attached to cell wall
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18. Capsules and slime layers  Attachment
 Protection from phagocytic
engulfment.
 Resistance to drying.
 Depot for waste products.
 Reservoir for certain
nutrients.
 protection
 These are structures surrounding the outside of the cell envelope. They
usually consist of polysaccharide; however, in certain bacilli they are
composed of a polypeptide (polyglutamic acid). Capsules are often lost
during in vitro culture.
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19. Flagella:
Polar monotrichous Polar amphitrichous
Spirillium Lophotrichous
Pseudomonas
Spirillum
Peritrichous
Salmonella
SEM of peritrichous strain Proteous
Note: bacteria without flagella are called atrichous.
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20. In Gram-negative Bacteria
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21. In Gram-positive Bacteria
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22. Motility
• Flagella consist of a • Almost all Spiral bacteria are
number of proteins motile
• About 1/2 of Bacilli are
including flagellin motile
 Identification of • Almost all Cocci are non-
motile
Bacteria
• Bacteria move toward
 Pathogenesis attractive stimuli and away
from harmful substances
 Motility of bacteria
and waste products in the
process known as chemotaxis
.
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24. Pilli or fimbrae
• Filamentous appendages that are
shorter, straighter and more numerous
that flagella
• Conjugation pilli found in certain group
of bacteria.
• Used for genetic material transfer.
• The transfer process is called
conjugation.
• Antibiotic resistance transfer.
• Atatchment pilli, Help bacteria adhare
to the surfaces, such as cell surfaces
and interface of water and air.
• It helps in colonization and
pathogenicity.
• found mostly in Gram (-) Bacteria
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25. E. coli (pathogenic)
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26. Cell Wall
• Main structural component -
Peptidoglycan
• Peptidoglycan
– repeating dissacharide units
– polypeptides
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27. Gram-Positive
Gram- Negative
Peptidoglycan
Peptidoglycan
Cell Membrane Membrane
Outer Membrane Periplasm
Peptidoglycan
Cytoplasmic Peptidoglycan
membrane
Periplasmic
space
Another
cell
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28. Bacterial Cell Walls
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29. Gram (+) Cell Wall
• NAM N-acetylmuramic acid
• NAG N- acetylglucosamine
• tetrapeptide side chains
• pentaglycine crossbridges
• teichoic acid
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30. Gram (-) Cell Wall
• NAM
• NAG
• Tetrapeptide side chains
• pentaglycine
• 2nd Outer membrane
– Lipopolysaccharides (LPS)
• Lipid A
• O Antigen
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31. Functions of Cell Wall
• Maintaining the cell's characteristic shape- the rigid
wall compensates for the flexibility of the
phospholipid membrane and keeps the cell from
assuming a spherical shape
• Countering the effects of osmotic pressure
• Providing attachment sites for bacteriophages
• Providing a rigid platform for surface appendages-
flagella, fimbriae, and pili all emanate from the wall
and extend beyond it
• Play an essential role in cell division
• Be the sites of major antigenic determinants of the
cell surface 。
• Resistance of Antibiotics
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32. Cell Membrane (Plasma
Membrane)
• 2 structural component
– double layer of phospholipids
– proteins
• Fluid Mosaic Model
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33. cytoplasmic membrane
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35. Functions of Cell
Membrane
• 1. Selective barrier (selectively
permeable)
• 2. Secretes exoenzymes
– amylases
– lipases
– peptidases
– CAN NOT UNDERGO PHAGOCYTOSIS
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36. Functions of Cell
Membrane
• 3. E.T.S. is located here
• 4. Enzymes for cell wall synthesis
• 5. If photosynthesis, enzymes are
located on membranous structures
called thylakoids
• 6. Mesosomes - invagination of cell
membrane attached to DNA (Binary
Fission)?
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37. Endospores  Identification of
Bacteria
(spores)  Pathogenesis
 Resistance
• Dormant cell
• Resistant to adverse
conditions • Produced when starved
- high temperatures • Contain calcium dipicolinate
- organic solvents DPA, Dipicolinic acid
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Bacillus

38. Method
Microscope
• Light Microscope
• Electron Microscope
• Darkfield Microscope
• Phase Contrast
Microscope
• Fluorescence Microscope
• Confocal Microscope ）
Staining Methods
 Simple staining;
 Differential staining (Gram
stain, Acid-fast stain),
 Special staining( Negative stain,
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40. Gram Stain
• 1884 Hans Christian Gram
• most important stain used in
Bacteriology
• Divides all Bacteria into 2 groups:
– Gram (+)
– Gram (-)
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41. Gram Staining
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42. Results
• Gram (+) Purple
• Gram (-) Red
• Difference - due to
structure of cell wall
– Gram (+) Thick cell wall
– Gram (-) Thin cell wall
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