CELL SHAPE

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CELL SHAPE Coccus - sphere -
coccus Single Diplococcus
two Clusters of cocci Strept
ococcus Bacillus- cylinder, rod Spiral
shape- Rigid spirilla
curved rods Flexible
spirochetes TYPICAL BACTERIAL CELL,
BINARY FISSION CELL COMPONENTS Cytoplasmic
membrane phospholipid bilayer fluid
mosaic model semi - permeable
barrier osmosis solvent (HOH),
solute isotonic, hypertonic, hypotonic
Cytoplasmic membrane protein functions Food
accumulation- group translocation active
transport Catalysis of metabolic pathways -
e.g., electron transport chain Cell wall
component synthesis Signal transduction - e.g.
chemotaxis CELL WALL Gram positive
organisms Peptidoglycan, Teichoic acid Gram
negative organisms Peptidoglycan Periplas
mic gel Lipoprotein Outer membrane
Phospholipid monolayer Lipopolysacchari
de Pores Peptidoglycan - polysaccharide
with amino acid components. N - acetyl
glucoseamine, N - acetyl muramic acid, Amino acid
side chains, Cross-linking
(interbridge) FLAGELLA - Flagellin, hook, outer
rings, inner ring Rotation counter
clockwise, clockwise, chemotaxis NUCLEOID
chromosome, haploid, double-stranded,
supercoil CYTOPLASM water, ribosomes, soluble
proteins, enzymes, low molecular weight
precursors, RNA, ATP PILI (SEX) FIMBRIAE
(ATTACHMENT) CAPSULE/GLYCOCALYX COMPARISON
EUCARYOTES AND PROCARYOTES SPORULATION
Endospores, durable, inert, survival mechanism,
germination
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Bacterial Cell Shape COCCUS - SPHERE -
COCCI Single - Micrococcus
luteus Diplococcus - Neisseria
gonorrhoeae Neisseria
meningitides Clusters - Staphylococcus
aureus Streptococcus - Streptococcus
pyogenes BACILLUS - ROD, CYLINDER -
BACILLI Bacillus anthracis ANTHRAX Coryn
ebacterium diphtheriae DIPHTHERIA pleomorphi
c SPIRAL RIGID - SPIRILLA Rhodospirillum
rubrum photosynthetic - CURVED Vibrio
cholerae CHOLERA FLEXIBLE - SPIROCHETES Treponem
a palladium SYPHILIS Borrelia burgdorferi
LYME DISEASE
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MICROORGANISMS Reproduce themselves
faithfully and the species continues to
occupy its niche in the environment Have
the capacity to change genetically Mutatio
n Genetic exchanges to be able to
respond to changing environments
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Typical Bacterial Cell - Binary Fission
1 x 3 µm
0 min 20 min 40 min 60 min
PLASMIDS SMALL EXTRA-CHROMO-SOMAL
DNA MOLECULES NOT NORMALLY REQUIRED FOR GROWTH
OFTEN CODE FOR TOXINS, DRUG RESISTANCE
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Accumulate food Oxidize food Energy Co
nvert food Low molecular weight
compounds Amino
acids Fatty acids
Monosaccharides Nucleotides S
ynthesize macromolecules Proteins, Lipids,
Polysaccharides, RNA, DNA Divide
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CYTOPLASMIC MEMBRANE - PHOSPHOLIPID BILAYER
outside
Hydrophobic fatty acids
8 nm
inside
Hydrophilic phosphates
FLUID MOSAIC STRUCTURE - VISCOUS 8 nm
thick selectively permeable - H2O osmosis -
isotonic solutions
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NET H2O change
OUT
IN
H2O X solute Y H2O LOW solute
HIGH H2O HIGH solute LOW
H2O X solute Y H2O HIGH solute
LOW H2O LOW solute HIGH
none
Isotonic
out
Hypertonic
in
Hypotonic
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CYTOPLASMIC MEMBRANES - FUNCTIONS
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CELL WALLS AND CYTOPLASMIC MEMBRANES
Gram Positive
Gram Negative
Teichoic acid
Pore
Lipopolysaccharide
Phospholipid monolayer
Lipoprotein
Periplasm
Phospholipid Bilayer
Proteins
Cytoplasm
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PEPTIDOGLYCAN REPEATING DISACCHARIDES WITH
AMINO ACID SIDE CHAINS
N-Acetyl Glucosamine
N-Acetyl Muramic Acid
Amino acid side chain
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L-Alanine
D-Glutamic acid
Diamino pimelic acid
D-Alanine
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GMGMGMG
Polysaccharide
INTERBRIDGE between side chains
Amino acid side chain
INTERBRIDGE Gram negative - covalent bond amino
acids 3-4 Gram positive - penta glycene between
amino acids 3-4
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(No Transcript)
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FLAGELLUM (-A) FLAGELLIN
hook
rings
14 nm x 10 µm
Cytoplasmic membrane
Outer membrane
Peptidoglycan
200 revolutions/sec Counter clockwise - forward
swim Clockwise - random tumble Chemotaxis - net
movement toward attractant, away from
repellent Cells swimming toward attraction tumble
less often. Net result movement toward
attraction
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MOTILITY
1. Swimming Extracellular flagella rotate E.
coli 20 - 90 micrometers/sec 2. Flexing Flage
llum located in periplasm rotates, cell flexes as
flagellum rotates Treponema
pallidum 3. Gliding Move over solid surfaces
without flagella Two forms of gliding A. Adven
turous (twitching) - done by individual
cells B. Social - done by many cells in unison
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Several mechanisms, one of which is pilus
extension (attachment to the solid surface) and
pilus retraction. (Type IV pili.) Examples of
twitching Nesseria gonorhoeae - spread over
body cell surfaces (?) Pseudomonas aeruginosa -
spread over body cell surfaces (?) 0.2
µM/sec Gram negative Opportunistic
pathogen Burn victims - bacteremia Cystic
fibrosis - chronic lung infection Ulcerative
keratitis - contact lens Example of social
gliding Myxococcus xanthus - cells form
fruiting bodies clumps containing
spores (Note M. xanthus can also
twitch) 4. Swarming Depends on
flagella Cells move in unison over solid
surface Escherichia coli, Salmonella
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Aggregate
- nutrients
Growth
Starvation
nutrients
Fruiting body
Spores
Myxococcus xanthus forms single-species biofilms
and exhibits social behaviors
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Myxococcus xanthus Fruiting Body Development
SEMs by Jerry Kuner
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ADHESIVE ORGANELLES
Contain adhesin (protein which binds
something) Function attachment Kinds 1.
pili/fimbriae 2. non-pilus adhesin (surface
protein)
PILI 7nm x 1µm
1 x 3 µm
examples Escherichia coli sex pili - attach
to female
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P Pilus - Escherichia Coli Cystitis
(bladder) Sticks to glycolipid on uroepithelial
cells and RBC (11 genes)
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Hemophilus influenzae HIB Pilus Respiratory epith
elium
E. coli P Pilus Uroepithelial cells
J. Bacteriol. 184.17. cover 2002
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CAPSULE / GLYCOCALYX
Streptococcus pneumoniae
Polysaccharide Pathogenicity factor
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Nucleoid - E. coli

• 1 chromosome - haploid
• 1100 µm circumference
• Supercoil - double strand
• 4.6 x 106 nucleotides / strand
• 5,300 genes
• 3 x 109 molecular weight
• 660 molecular weight / nucleotide pair

Cytoplasm HOH, soluble materials - low molecular
weight precursors Enzymes, ribosomes, RNA
transfer messenger, ATP
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PROKARYOTE GENOMES
Genome all genetic information of an organism
Number Nucleotide Pairs
Number Genes
E. coli 4.6 x 106 5,300 Haemophilus 1.8
x 106 1,800 influenzae Methanococcus 1.7 x
106 1,800 jannaschii (archea)
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FIG 3.39 E COLI NUCLEOIDS
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BACTERIAL (E. COLI) CELL COMPOSITION
NUMBER
MOLECULES MOL WT OF
DIFFERENT PER CELL CELL
KINDS OF MOLECULES
DNA 1 1-2 3 X 109
1 PROTEIN 5,000 2 X 106 3 4 X 104
15 RNA (TOTAL) 6 RIBOSOMAL 3
20,000 EACH TRANSFER 60
200,000 2,000
MESSENGER 600 1500
PHOSPHOLIPID MANY 22,000,000
700 3 RIBOSOMES 1
20,000 PEPTIDOGLYCAN 1
1 10 X 109 1 OTHER
CELL WALL COMPONENTS, LOW MOLECULAR WEIGHT
PRECURSORS, VITAMINS WATER 70

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EUCARYOTES
PROCARYOTES
1. True nucleus chromosomes in nuclear
membrane Introns common 2. Divide by mitosis 3.
Sexual reproduction meiosis (eggs, sperm) 4.
Mitochondria 5. Chloroplasts 6. Cell
walls animals - none plants -
cellulose fungi - chitin 7. Ribosomes - 80S 8.
Size - 8 to 100 micron diameter
1. Nucleoid Introns rare 2. Divide by
binary fission 3. Primitive sex 4. None 5. None
- chromatophores 6. Present, with
peptidoglycan 7. Ribosomes - 70S 8. Size -
1 x 3 microns
Macroscopic microbe - Epulopiscium fishelsoni gt
50 micron diameter gt 500 micron length
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ENDOSPORES
Dormant, inert, durable Resist chemicals (e.g.,
bleach), heat, drying, radiation Formed by
growing cells
Nucleoid
Cell membrane
spore coat
GERMINATION - spores resume metabolism and form
growing cells
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BOTULISM- Clostridium botulinum spores on
vegetables, smoked fish, etc. Spores survive
home canning process, Germinate in the anaerobic
environment of the canned food, cells grow and
secrete neurotoxin People ingest the toxin,
absorb it from their intestine. Neurotoxin
causes paralysis and respiratory
failure Treatment - anti botulism antitoxin
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ANTHRAX- (disease of cattle, sometimes spread
to humans) Cutaneous anthrax Bacillus
anthracis spores in soil or contaminated animal
products. Enter body through wounds,
germinate and grow. Set up local infection
(sometimes it spreads) Pulmonary
anthrax Spores are breathed, germinate in the
lungs, infect lungs, massive swelling, rapid
death
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TETANUS- Clostridium tetani spores - ubiquitous
in soil Enter body through wounds, germinate,
grow at the site of infection, secrete
neurotoxin Neurotoxin spreads through nerves to
spinal cord, causes convulsions and
death Neonatal tetanus 500,00 people die/year
in the world Tetanus vaccinations in U.S. (DT
or DPT)