Download This is a pore in human skin and the yellow spheres are bacteria

BACTERIA
Chapter 19.1
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This is a
pore in
human skin
and the
yellow
spheres are
bacteria
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Clean skin has about 20 million
bacteria per square inch
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Evolution/Classification




Prokaryotes
The oldest fossils known, nearly 3.5
billion years old, are fossils of bacterialike organisms.
Evolution has yielded many species
adapted to survive where no other
organisms can.
Grouped based on:



Structure, physiology, molecular
Composition, reaction to specific types of
stain (Gram Positive/Gram Negative).
Eubacteria= Germs/bacteria
Archaebacteria
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Kingdom Archaebacteria


First discovered in extreme environments
Methanogens: Harvest energy by
converting H2 and CO2 into methane gas



Anaerobic, live in intestinal tracts
Extreme halophiles: Salt loving, live in
Great Salt Lake, and Dead sea.
Thermoacidophiles: Live in acid
environments and high temps.

Hot Springs, volcanic vents
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
Depending on the
species, bacteria
can be aerobic
which means they
require oxygen to
live
or
anaerobic which
means oxygen is
deadly to them.
Green patches are green sulfur
bacteria. The rust patches are
colonies of purple non sulfur
bacteria. The red patches are
purple sulfur bacteria.
Chemosynthetic bacteria use the
sulfur in the “smoke” for energy
to make ATP.
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The red color of this snow is due to a blue-green bacteria
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Kingdom Eubacteria

Can have one of three basic shapes
1. Bacilli – rod-shaped
2. Spirilla – spiral-shaped
3. Cocci – sphere-shaped
•Staphylo – grape-like
clusters
•Strepto – in chains
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BACTERIA PICS
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Bacillus
bacteria
are rod
shaped
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Coccus
bacteria
are ball
shaped
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Spirillium bacteria have a corkscrew shape
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Diplo-bacteria
occur in pairs,
such as the
diplococcus
bacteria that
causes
gonorrhea
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Staphylo occur in
clumps, such as
this
staphylococcus
that causes
infections of
cuts
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Strepto- occur
in chains of
bacteria, such
as this
streptococcus
bacteria that
causes some
types of sore
throats
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Cyanobacteria
You may have seen
them as "green slime"
in your aquarium or in
a pond.
Cyanobacteria can do
"modern
photosynthesis", which
is the kind that makes
oxygen from water. All
plants do this kind of
photosynthesis and
inherited the ability
from the cyanobacteria.



The Gram stain, which divides most
clinically significant bacteria into two
main groups, is the first step in bacterial
identification.
Bacteria stained purple are Gram + their cell walls have thick petidoglycan.
Bacteria stained pink are Gram – their
cell walls have have thin peptidoglycan
and lipopolysaccharides.
STRUCTURE OF BACTERIA
Structure
Function
Cell Wall
Protects and gives shape
Outer
Membrane
Protects against antibodies (Gram Neg. Only)
Cell
Membrane
Regulates movement of materials, contains
enzymes important to cellular respiration
Cytoplasm
Contains DNA, ribosomes, essential compounds
Chromosome
Carries genetic information
Plasmid
Contains some genes obtained through recomb.
Capsule &
Protects the cell and assist in attaching cell to
Slime Layer other surfaces
Endospore
Protects cell agains harsh enviornments
Pilus
Assists the cell in attaching to other surfaces
Flagellum
Moves the cell
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No Nucleus-DNA in Cytoplasm
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Eubacteria - Nutrition and Growth

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Heterotrophic or Autotrophic
Some are Photoautotrophs – Use sunlight for Energy
Some are Chemoautotrophs.
Many are Obligate Anaerobes. (live w/o O2)
 Ex.

Some are Faculatative Anaerobes (can live w/ or w/o
O2)
 Ex.


Clostridium tetani – Tetanus
Escherichia Coli
Some are Obligate Aerobes (need O2 to survive)
 Ex.) Mycobacterium tuberculosis
Temperature requirements

Some are Thermophilic, Some prefer acidic envmt.
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REPRODUCTION
IN
BACTERIA
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BACTERIA REPRODUCES
BY FISSION
First the chromosomal DNA
makes a copy
The DNA replicates
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NEXT THE CYTOPLASM
AND CELL DIVIDES
The two resulting cells are
exactly the same
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In addition to
the large
chromosomal
DNA, bacteria
have many
small loops of
DNA called
Plasmids
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
Bacteria can reproduce sexually conjugation or asexually - binary fission.
CONJUGATION
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Bacteria and Disease
Disease
Pathogen
Areas
affected
Mode of
transmission
Botulism
Clostridium botulinum
Nerves
Improperly
preserved food
Cholera
Vibrio cholerae
Intestine
Contaminated water
Dental Caries
Streptococcus mutans,
sanguis, salivarius
Teeth
Environment to
mouth
Gonorrhea
Neisseria gonorrhoeae
Urethra,
fallopian
Sexual contact
Lyme disease
Berrelia burgdorferi
Skin, joints
Tick bite
Rocky
Mountain SF
Rickettsia recketsii
Blood, skin
Tick bite
Salmonella
Salmonella
Intestine
Contaminated food,
water
Strep throat
Streptococcus pyogenes
URT, blood,
skin
Sneezes, coughs,
etc.
Tetanus
Costridium tetani
Nerves
Contaminated
wounds
Tuberculosis
Mycobacterium tuberculosis
Lung,
bones
coughs
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Helicobacter
pylori
is the
pathogenic
bacteria
that can
causes ulcers
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Leprosy is a
bacterial
infection
that
decreases
blood flow to
the
extremities
resulting in
the
deterioration
of toes, ears,
the nose and
the fingers.
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BOTULISM
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ROCKY MOUNTAIN SF
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LYME DISEASE
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SALMONELLA
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STREP THROAT
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TUBERCULOSIS
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Common Antibiotics
Antibiotic
Mechanism
Target bacteria
Penicillin
Inhibits cell wall synthesis
Gram Positive
Ampicillin
Inhibits cell wall synthesis
Broad spectrum
Bacitracin
Inhibits cell wall synthesis
Gram Positive – Skin
Ointment
Cephalosporin
Inhibits cell wall synthesis
Gram Positive
Tetracycline
Inhibits Protein Synthesis
Broad spectrum
Streptomycin
Inhibits Protein Synthesis
Gram Neg. tuberculosis
Sulfa drug
Inhibits cell metabolism
Bacterial meningitis,
UTI
Rifampin
Inhibits RNA synthesis
Gram Pos., some Neg.
Quinolines
Inhibits DNA Synthesis
UTI
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Some Final Information


Because antibiotics have been overused,
many diseases that were once easy to
treat are becoming more difficult to
treat.
Some Bacteria are Useful



Ex. Producing and Processing food
Breaking down dead organic material
Make unripened cheese like ricotta and
cottage by breaking down the protein in
milk.
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