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BACTERIA
CLS 311: Basic Microbiology
Mrs. Ohoud alhumaidan
OUTLINE
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1.
2.
3.
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6.
7.
History
Prokaryote
Introduction
Bacteria size & shape ( Morphology + arrangement)
Reproduction
Classification
Structure of bacterial cell
Capsule
Cell wall
Cell membrane ( cytoplasmic membrane)
Cytoplasm , chromosome and plasmid
Flagella
Pilli
Endospore
HISTORY
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Anton van Leeuwenhoek
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Louis Pasteur
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Robert Koch
MICROORGANISMS
Cellular
A cellular
Prokaryotes
Viruses
Archaea
Fungi
Bacteria
Protozoae
Eukaryotes
.
PROKARYOTES
Prokaryotic cells possess simpler structures than eukaryotic cells , 
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There are two major types of prokaryotes:
1.
Bacteria.
2.
Archaea (also called archaebacteria)
INTRODUCTION
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Bacteriology
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Bacteria (plural), Bacterium (singular).
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Binary fusion
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Generation time
BACTERIA SIZE & SHAPE
 Size
:
Ranging between 0.2m to 10.0 m in length
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Unit of microbial measurement is the micrometer (m), formerly micron ()
which is equal to:
1m = 1/1000 of a millimeter (mm)
 Shape
1)
2)
3)
4)
( morphology )
Rods ( bacilli )
Cocci
Spiral or curved shape
pleomorphic
BACTERIAL MORPHOLOGY
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1- Shape:
Bacilli (bacillus, singular)
– rod shaped organisms
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Cocci (coccus, singular) –
spherical or round
organisms
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Spirilla (spirillum,
singular) – spiralled or
comma-shaped
organisms
BACTERIAL MORPHOLOGY
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2-Arrangement : A- cocci
BACTERIAL MORPHOLOGY
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2-Arrangement : B- bacilli
REPRODUCTION
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Binary fission
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Two factors that affect bacterial
arrangements:
•
Plane of division
•
Position taken after cell division
REPRODUCTION
Cocci arrangement
diplococci
Example
Neisseria gonorrhea
Chains
Grapelike clusters
Streptococci,
Staphylococci
Groups of four (tetrads )
Peptococcu
Packets of eight
Sarcinae
CLASSIFICATION
Kingdom
Phylum
Class
Order
Family
Genus
Species
Bacteria
Proteobacteria
Gamma Proteobacteria
Enterobacteriales
Enterobacteriaceae
Escherichia
Escherichia coli
e.g. Escherichia coli
STRUCTURE OF BACTERIAL CELL
( CHECK CHAPTER 3)
Cell Envelope :
Made up of two to three layers:

1.
Cell wall .
2.
Cell membrane .
3.
Capsule : (in some species of bacteria )
STRUCTURE OF BACTERIAL CELL
1- CAPSULE
Made of polysaccharide
 Can be detected by capsule staining (
negative stain )
 Function of bacterial capsule
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2- CELL WALL

cell wall provides strength , rigidity and protection

Peptidoglycan

Classification of bacteria according to cell wall :
1- have cell wall : Gram positive & Gram negative
2- lack of cell wall : e.g. : Mycoplasma ( AFB )
PEPTIDOGLYCAN
Gram stain
DIFFERENCES BETWEEN G+ & G -- (CHECK TABLE 4-5 ( CHAPTER 4)

Gram positive

Gram negative
DIFFERENCES BETWEEN G+ & G- CELL WALL
FIGURE 3-8 (CHAPTER 4)
3-CELL MEMBRANE
CYTOPLASM & CHROMOSOME & PLASMID
Cytoplasm:
It is a gel-like matrix composed of water, enzymes,
nutrients, wastes, and gases .
 Chromosome :
bacterial cells possess only one chromosome .
 Plasmid :
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Plasmids are small extrachromosomal genetic structures carried
by many strains of bacteria.
Like the chromosome, plasmids are made of a circular piece of
DNA. Unlike the chromosome, they are not involved in
reproduction.
FLAGELLA
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Flagella (singular, flagellum) are long hair-like
structures that can be found at either or both ends of
a bacterium or all over its surface.
Function of the Flagella
PILLI
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Many species of bacteria have pili (singular, pilus),
short hair-like structures emerging from all around
the outside cell surface.
Type of Pilli :
Function of the Pilli :
ENDOSPORES
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Bacterial spores called endospore
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Sporulation
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Eg ; clostredium , Bacillus
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Function of endospores
 Several
species of endospore-formers can
cause a disease :
 clostridium botulinum>> botulism
 Clostridium tetani >> tetanus
 Clostridiun prefrenges >>gas gangren