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BACTERIA
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Bacteria are very small
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This is a pore
in human
skin and the
yellow
spheres are
bacteria
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Bacteria are
very small
compared
to cells
with nuclei
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Bacteria
Bacteria
compared
to a white
blood
cell that
is going
to eat it
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Clean skin has about 20 million
bacteria per square inch
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Evolution/Classification
•
•
•
•
Most numerous on Earth
Most Ancient
Microscopic Prokaryotes
Evolution has yielded many species adapted to
survive where no other organisms can.
• Grouped based on:
– Structure, physiology, molec. Composition
reaction to specific types of stain.
– 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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Volcanic
vents on the
sea floor
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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
Kingdom Eubacteria
• Can have one of three basic shapes
1. Bacilli – rod-shaped
2. Spirilla – spiral-shaped
3. Cocci – sphere-shaped
Streptococci – in chains
Staphylococci – grape-like
clusters
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BACTERIA PICS
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Bacillus
bacteria
are rod or
sausage
shaped
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Coccus
bacteria
are
sphere
or
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 bacteria occur
in clumps, such
as this
staphylococcus
bacteria that
causes common
infections of
cuts
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Streptobacteria occur
in chains of
bacteria, such
as this
streptococcus
bacteria that
causes some
types of sore
throats
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Spirillium bacteria
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Diplobacillus
bacteria
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Streptococcus
bacteria
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Staphylococcus bacteria
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The tip of a
needle
The red and
yellow dots
are bacteria
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Gram Stain
• Gram-positive retain stain and
appear purple
–Have thicker layer in cell
wall.
• Gram-negative do not retain
stain and take second pink
stain instead.
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No Nucleus-DNA in Cytoplasm
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Nutrition and Growth
•
•
•
•
Heterotrophic or Autotrophic
Some are Photoautotrophs – Use sunlight for Energy
Some are Chemoautotrophs.
Many are Obligate Anaerobes.
– Oxygen = Death
• Ex. Clostridium tetani – Tetanus
• Some are Faculatative Anaerobes
– With or without Oxygen
• Ex. Escherichia Coli
• Some are Obligate Aerobes
– Ex.) Mycobacterium tuberculosis
• Temperature requirements
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– Some are Thermophilic, Some prefer acidic envmt.
These
heterotrophic
bacteria
digest oil -remember oil
is partially
decayed plant
and animal
cells
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REPRODUCTION
IN
BACTERIA
(please add to notes)
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No Nucleus-DNA in Cytoplasm
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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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Genetic Recombination
Characteristic
Transformation Conjugation
Transduction
Method of DNA Across cell
Transfer
wall and cell
membrane of
recipient
Through a
conjugation
bridge
between two
cells
By a virus
Plasmid
transfer
Yes
Yes
Not likely
Chromosome
transfer
No
Sometimes
No
Antibiotic
resistance
acquired
Yes
Yes
Sometimes
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TRANSFORMATION
This plasmid of
DNA is new to
the bacteria –
added by
transformation!
Produces the
glowing protein
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CONJUGATION
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TRANSDUCTION
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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, Sneezes, coughs,
skin
etc.
Tetanus
Costridium tetani
Nerves
Contaminated 38
wounds
Some
bacteria
cause
diseases -Disease
causing
bacteria
are call
PATHOGENIC
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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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CHOLERA
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DENTAL CARIES
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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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VIRUSES
Non-living but depends on the living!
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STRUCTURE
•
•
•
•
•
Nonliving
Composed of Nucleic acid and protein
Cause many diseases
Virology – Study of Viruses
Comparison of Viruses and Cells below
Char. Of Life
Virus
Cell
Growth
No
Yes
Homeostasis
No
Yes
Metabolism
No
Yes
Mutation
Yes
Yes
Nucleic acid
DNA or RNA
DNA
Reproduction
Only within host cell
Independently by
cell division
Structure
Nucleic acid core, protein
covering, some have
envelope
Cytoplasm, cell
membrane, etc..
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Here is a non-enveloped bacteria
virus inserting it’s DNA into a
bacterial cell.
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Some virus are pushed out by the cell, taking
some of the cell membrane with them.
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Characteristics of Viruses
• 2 essential features
• 1. Nucleic Acid
– May be DNA or RNA
– Helical, closed loop, or long strand
• 2. Protein Coat – called CAPSID
• Some have ENVELOPE
– Ex. Influenza, chickepox, herpes simplex, HIV
• VIRAL SHAPE
– Icosahedron – 20 triangular faces
• Ex.) herpes, chickenpox, polio
– Helix – Coiled spring
• EX.)Rabies, measles, tobacco mosaic
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All viruses have two main parts:
1. DNA or RNA – genetic info
2. Capsid – a protein encasement
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•
Grouping
Viruses
Grouped according to:
– Presence of Capsid and envelope – shape
– RNA or DNA, single or double stranded – struct.
Viral Group
Nucleic Acid
Shape and Structure
Example
Papovaviruses
DNA
Icosahedral, non-env.
Warts, cancer
Adenoviruses
DNA
Icosahedral, non-env.
Resp. & intestinal
infections
Herpesviruses
DNA
Icosahedral, enveloped
Herpes simplex,
chicken pox, mono,
shingles
Poxviruses
DNA
Complex brick, enveloped
Small pox, cow pox
Picornaviruses
RNA
Icosahedral, non-env.
Polio, hepatitis,
cancer
Myxoviruses
RNA
Helical, enveloped
Influenza A, B, C
Rhabdoviruses
RNA
Helical, enveloped
Rabies
Retroviruses
RNA
Icosahedral, enveloped
AIDS, cancer
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Grouping Viruses
• Viroids- The smallest known particle that
can replicate.
– Disrupt plant cell metabolism
– Can destroy entire crops
• Prions – Abnormal forms of proteins that
clump together inside cells.
– Clumping eventually kills the cell
– Examples
• Scrapie – in sheep
• Mad Cow Disease
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PRIONS – man-made problem?
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Viral Replication
• Can replicate only by invading host cell and
using its enzyme and organelles.
• Bacteriophage – viruses that infect bacteria
– Used to study viruses
• Lytic Cycle
– Viral genome is released into the host cell
– Replication follows immediately
– Cellular components used to make new
viruses
– Viral enzyme kills cell.
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Viral Replication Picture
http://www.mcgrawhill.ca/school/schoolGraphics/biology2_1.mpg
Click Movie to
Play
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Replication cont’
• Lysogenic Cycle
– Nucleic acid of virus becomes part of
the host cell’s chromosome
– Nucleic acid remains in the cell in this
form for many generations
– HIV follows this pattern
– HIV infects WBC and remains as
proviruses
– As immune system fails, opportunistic
infections occur = AIDS
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Here is a classic picture of HIV viral
progeny being released from the
surface of a T- cell. Notice the
membrane coating they receive.
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Viruses and Human Disease
• Control and Prevention of spread.
– Vaccination & Antiviral drugs
• Ex.) chickenpox vaccine, AZT, Acyclovir, protease
inhibitors.
• Emerging Viruses – exist in isolated
habitats
– Do not usually infect humans unless
environmental conditions favor contact.
• Several viruses are now linked to cancers
such as leukemia, liver cancer, Burkitt’s
lymphoma, cervical cancer.
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PAPOVAVIRUSES
BACK
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ADENOVIRUSES
BACK
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HERPESVIRUSES
BACK
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POXVIRUSES
BACK
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PICORNAVIRUSES
BACK
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After polio infections,
the killer T-cell have
destroyed the motor
neurons that are
producing the virus.
The result is a loss of
muscle control
including the
diaphragm. The
iron lung changes the
pressure to pump air
in and out of the
lungs.
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Which US President had polio?
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MYXOVIRUSES
BACK
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RHABDOVIRUSES
BACK
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RETROVIRUSES
BACK
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What does bacteria have to do with DNA
technology?
• Bacteria are simple
• Bacteria have DNA that is made of
nucleotides (A,T,G,C)
• Bacteria can be grown quickly and easily
– Give them food, warmth and dark (like inside
you shoe) and they will multiply like mad
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(binary fission)
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• Bacteria have plasmids – extra DNA in the
form of a circle
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• Plasmids are DNA – made out of A,T,C,G
nucleotides
• The same nucleotides found in human
DNA, plant DNA, dog DNA, fish DNA,
fungus DNA
• Get it – it’s all the same molecule
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• So… why not take out a plasmid, cut it
apart and add any other DNA piece that
we want!
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• Then put it back in the bacteria and grow
more bacteria with that new plasmid that
http://www.learner.org/channel/courses/biology/archive/ani
wemations.html
have created! Hmmm?
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• How could rDNA and transformation be
useful?
• To be answered in DNA technology
presentations
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• Transduction – viruses attack cells
• Bacteriophages: like tiny little syringes that
inject DNA into the cell
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Look at how the virus infects
http://www.slic2.wsu.edu:82/hurlbert/micro10
1/pages/Chap11.html
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Viral Infections
• Ebola
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• How could scientists use viruses for DNA
technology
• To be answered in DNA technology
presentations
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Time to take ownership
• Here’s what you should have down by the
end of the class Wednesday:
– Bacteria and virus structures
– Types of bacteria
– Types of viruses
– How bacteria and viruses cause infection
– How bacteria and viruses can be useful DNA
technology tools
– Overview of various DNA technologies – refer
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to chapter 13