In the first chapter, we introduced a general outline on what will be of this subject. Now we start to examine details of microorganisms. Let

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In the first chapter, we introduced a general
outline on what will be of this subject. Now we
start to examine details of microorganisms. Lets
see what microorganisms look like and what are
made of.
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Chapter 2Structure of Bacteria
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Chemical composition of a prokaryotic cell
2.1
Macromolecules (???) protein,
polysaccharide, lipids, DNA, RNA, 96
(dw) Monomers (?????) amino acids
and precursors, sugars and precursors 3
Inorganic ions K, Mg2, Ca2, Fe2,
Mn2, Cu2?Co2?Zn21
4
Macromolecules Nucleoside base sugar
OH

• Bases
• adenine (A), cytosine (C),
• guanine (G), thymine (T)
• RNA uses uracil (U)
• instead of thymine

Base
CH2
O
P
HO
O
C
C
H
H
O
C
C
H
H
H or OH
H

• Sugar
• RNA ribose (OH)
• DNA deoxyribose (H)

Remember that carbon in sugar is numbered in
sequence!!! How they are numbered?
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U ???
T ????
C ???
G ???
A ???
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Hydrogen bond
T
C
Question if a cell DNA contains more GC than
AT, is it harder or easier to separate two
complementary chains?
A
G
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Macromolecules protein
???????
? ?
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2.2 Size and shape of Bacteria

• Average bacteria 0.5 - 2.0 um in diam.
• Surface area 12 µm2
• Volume is 4 µm
• Surface area to volume is 31
• Typical eukaryote cell SA/Vol is 0.31
• Food enters through SA, quickly reaches all parts
  of bacteria
• Eukaroytes need structures organelles

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Approximate size of micro-organisms compared to a
typical eukaryotic cell.
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There are two types of cells prokaryotic vs.
eukaryotic
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Shapes of Bacteria

• Coccus (??)
• Chain Streptoccus
• Cluster Staphylococcus
• Bacillus (??)
• Chain Streptobacillus
• Coccobacillus (???)
• Vibrio curved (??)
• Spirillum (???)
• Spirochete (???)
• Square (??)
• Star (??)

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Streptococci (???) showing dividing manner
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Tetradococci (????)
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Staphylococci (????)
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 ?? (coccus)???????????????
???(Coccus)
?????????????????????????(Diplococcus)
???????????????????????????(Streptococcus)
 ????????????????????????????(Tetrads)
?????????????,????????????????????????????(Sarcina
lutea)
???????????????????????(Staphylococcus)
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Square cell Cyanobacteria
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2.3 Bacterial Structures
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Flagella (??)

• Motility - movement
• Swarming (??) occurs with some bacteria
• Spread across Petri Dish
• Proteus (???) species most evident
• Arrangement basis for classification
• Monotrichous (????) 1 flagella
• Lophotrichous (????) tuft at one end
• Amphitrichous (????) both ends
• Peritrichous(????) all around bacteria
• Observe Picture in Micro Lab.

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Pili (??)

• Short protein appendages
• smaller than flagella
• Adhere bacteria to surfaces
• E. coli has numerous types
• K88, K99, F41, etc.
• Antibodies to will block adherance
• F-pilus used in conjugation
• Exchange of genetic information
• Flotation increase boyancy
• Pellicle (scum on water)
• More oxygen on surface

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F-Pilus for Conjugation(??)
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Capsule or Slime Layer(??/??)

• Glycocalyx (??)- Polysaccharide on external
  surface
• Adhere bacteria to surface
• Prevents phagocytosis(????)
• Prevent water from loss

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Cytoplasm(???)
The part inside the membrane

• 80 Water by weight, 20 salts-proteins
• Osmotic (???) shock important
• DNA is circular(??DNA), haploid (??)
• More efficient grows quicker
• Mutations (??) allow adaptation to environment
  quicker
• Plasmids (??) circular DNA independent to
  chromosome (?????????DNA)
• Antibiotic resistance (? ???)
• No organelles??? (mitochondria, Golgi, etc.)

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Cell Membrane(???)
???
???

• Bilayer phospholipid
• Water can penetrate
• Flexible
• Not strong, ruptures (??) easily
• Osmotic pressure created by cytoplasm

???????(?)?????(?)
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???
???
? ? ?
??
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??
????
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???
???
??
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Differences of membrane lipids between Archaea
and other organisms
?????
??
??????????????????????????? ??????????????????
Branches
???
??
????????????????
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Cell Wall

• Peptido-glycan (?-?) polymer (amino acids
  sugars)
• Unique (??) to bacteria
• Sugars NAG NAM
• N-acetylglucosamine (N-???????)
• N-acetymuramic acid (N- ?????)
• D form of Amino acids used not L form
• Hard to break down D form
• Amino acids cross link NAG NAM

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?20 ??????? NAGN-?????? NAMN-?????
?
??
???
L-???
D-???
???????
D-???
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Cell wall structure of Gram negative bacteria
G-???????
??
???
??
???
???
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??????
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???
??????,????????????
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??
??
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Cell wall structure of Gram positive
bacteria ??????(G)????
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Cell Wall Summary

• Determine shape of bacteria
• Strength prevents osmotic rupture
• 20-40 of bacteria
• Unique to bacteria
• Some antibiotics effect directly
• Penicillin

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Cell Wall
Teichoic Acids ??(?)?

• Gram only
• Glycerol, Phosphates, Ribitol
• Attachment for Phages

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Lipopolysaccharide (LPS)

• Endotoxin or Pyrogen
• Fever causing
• Toxin nomenclature
• Endo- part of bacteria
• Exo- excreted into environment
• Structure
• Lipid A
• Polysaccharide
• O Antigen of E. coli, Salmonella
• G- bacteria only
• Alcohol/Acetone removes

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LPS (contd)

• Functions
• Toxic kills mice, pigs, humans
• G- septicemia death due to LPS
• Pyrogen causes fever
• DPT vaccination always causes fevers
• Adjuvant stimulates immunity
• Heat Resistant hard to remove
• Detection (all topical IV products)
• Rabbits (measure fever)
• Horse shoe crab (Amoebocytes Lyse in presence of
  LPS)

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LPS (contd.)

• Appearance of Colonies
• Mucoid Smooth (lots of LPS or capsule)
• Dry Rough (little LPS or capsule)
• O Antigen of Salmonella and E. coli
• 2,000 different O Ags of Salmonella
• 100s different O Ags of E. coli
• E. coli O157
• O Ags differ in Sugars, not Lipid A

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Endospores(???????)

• Resistant structure
• Heat, irradiation, cold
• Boiling gt1 hr still viable
• Takes time and energy to make spores
• Location important in classification
• Central, Subterminal, Terminal
• Bacillus stearothermophilus(????) -spores
• Used for quality control of heat sterilization
  equipment
• Bacillus anthracis - spores
• Used in biological warfare

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Bacillus anthracis(????? ). Gram stain. The cells
have characteristic squared ends(??). The
endospores are ellipsoidal(??) shaped and located
centrally in the sporangium. The spores are
highly refractile (??) to light and resistant to
staining.
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Bacillus thuringiensis. Phase Photomicrograph of
vegetative cells, intracellular spores (light)
and parasporal crystals (dark) (?????) .
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G vs. G-

• G
• Thicker cell wall
• Teichoic Acids
• G-
• Endotoxin - LPS
• Which are more sensitive to Penicllin?
• Alcohol/Acetone affects which more?

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Prokaryotes vs. Eukaryotes

• Cell Wall
• Teichoic Acids
• LPS
• Endospores
• Circular DNA
• Plasmids

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Eukaryote Cell Structure