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BACTERIA
Chapter 20.2
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Agenda

November 10 – Day 4
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
Bacteria Notes
Bacterial Disease Poster Project
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This is a
pore in
human skin
and the
yellow
spheres are
bacteria
3
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 bacteria-like
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

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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
o Can live in colonies
•Strepto – in chains
•Staphylo – grape-like
clusters
•Diplo – pairs
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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/violet are Gram +
- their cell walls have thick peptidoglycan.
Bacteria stained pink are Gram – - Their
cell walls 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
recombination
Capsule &
Slime Layer
Protects the cell and assist in attaching cell to
other surfaces
Endospore
Protects cell against harsh environments
Pilus
Assists the cell in attaching to other cells
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
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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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19.3 Diseases Caused by
Bacteria
Key Concepts:
1. How do Bacteria cause disease?
2. How can Bacterial growth be
controlled?
Vocabulary: Pathogen, Vaccine,
Antibiotic
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Microorganisms Cause Disease

The Who

Louis Pasteur – French Chemist
 Disproved
Theory of Spontaneous
Generation


Chapter 1 – What is it?
Germ Theory of Disease
 Observed
and hypothesized that
microorganisms caused infection and
disease
 Encouraged doctors and surgeons to
sanitize and sterilize themselves and
equipment
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Microorganisms Cause Disease

The How

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
Some Bacteria need room to grow and
reproduce, in order to do so, they destroy
living tissue for food
Other types of bacteria create toxins during
growth and development which can destroy
living tissue
Disease results when bacteria interfere with
an organisms ability to function properly.
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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
Rocky
Mountain SF
Rickettsia recketsii
Blood,
skin
Tick bite
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
Berrelia burgdorferi Affects
Skin and
joints
Transmitted
by a Tick
bite
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Salmonella
Affects the
Intestine
Transmitted
through
contaminated
food and water
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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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Antibiotics
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Anti – against
Bio- life
= against life, so antibiotics will only kill
living things, which means they are
ineffective against viruses (which aren’t
alive)
How do they work?

They block the growth and reproduction of
bacteria
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Vaccines
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An injection of a weakened of killed pathogen
Prompts the body to begin the primary
immune response
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Secondary Immune response is then
activated
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What is the Primary Immune Response?
What is the Secondary Immune Response?
Once the person comes in contact with the
bacteria for a 2nd time, they will have
antibodies ready and present to fight the
disease
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How to kill Bacteria
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Sterilization by Heat – Most bacteria can not
survive high temperatures, so pathogens
will be killed by exposure to high heat
Disinfectants – chemical solutions that kill
pathogens
Food Storage/Processing –
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Refrigerator storage slows bacterial reproduction
Boiling, Frying, Steaming – heat food to the
point at which bacteria will be killed
Preserved food – use of vinegar, salt and sugar
to prevent food from spoiling due to bacterial
contamination
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Some Final Information

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Because antibiotics have been overused,
many diseases that were once easy to
treat are becoming more difficult to
treat. MRSA
Some Bacteria are Useful

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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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