BACTERIA
Biology Chapter 19
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Bacteria are very small
2
This is a
pore in
human skin
and the
yellow
spheres are
bacteria
3
Bacteria
are very
small
compared to
cells
with
nuclei
4
Bacteria
Bacteria
compared
to a white
blood cell
that is
going to
eat it
5
Clean skin has about 20 million
bacteria per square inch
6
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
8
Volcanic vents
on the sea floor
9
Chemosynthetic bacteria use the
sulfur in the “smoke” for energy
to make ATP.
10
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
Staphylococci – grape-like
clusters
Streptococci – in chains
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BACTERIA PICS
13
Bacillus
bacteria are
rod or
sausage
shaped
14
Coccus
bacteria
are
sphere
or
ball
shaped
15
Spirillium bacteria have a corkscrew shape
16
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
18
Strepto- bacteria
occur in chains of
bacteria, such as
this streptococcus
bacteria that
causes some
types of sore
throats
19
Spirillium 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.
Phylum
Shape
Motility
Metabolism
Gram
reacion
Cyanobacteria
Bacilli,
Cocci
Gliding,
some nonmotile
Aerobic,
Gramphotosynthetic negative
autotrophic
Spirochetes
Spirals
Corkscrew
Aerobic, and
anaerobic;
heterotrophic
Gram-Pos
Bacilli,
cocci
Flagella;
some nonmotile
Aer/anaer.;
Mostly
heterotrophic, gramphotosynthetic positive
Proteobacteria
Bacilli,
cocci,
spiral
Flagella;
some nonmotile
Aer/anaer.;
heterotrophic,
photosynthetic
autotrophic
Gramnegative
Gramnegative
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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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Nutrition and Growth




Heterotrophic or Autotrophic
Some are Photoautotrophs – Use sunlight for Energy
Some are Chemoautotrophs – Use chemicals for nrg
Many are Obligate Anaerobes.
 Oxygen = Death
 Ex.

Some are Facultative Anaerobes
 With or without Oxygen
 Ex.


Clostridium tetani – Tetanus
Escherichia Coli
Some are Obligate Aerobes (need oxygen)
 Ex.) Mycobacterium tuberculosis
Temperature requirements

Some are Thermophilic, Some prefer acidic envmt.
27
These
heterotrophic
bacteria digest
oil -- remember
oil is partially
decayed plant
and animal
cells
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REPRODUCTION
IN
BACTERIA
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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
31
NEXT THE CYTOPLASM
AND CELL DIVIDES
The two resulting cells
are exactly the same
32
In addition to
the large
chromosomal
DNA, bacteria
have many
small loops of
DNA called
Plasmids
33
Genetic Recombination

Nonreproductive Methods bacteria can acquire new
genetic material.
Characteristic
Transformation Conjugation
Transduction
Method of DNA Across cell wall
Transfer
and cell
membrane of
recepient
Through a
By a virus
conjugation
bridge between
two cells
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,
skin
Sneezes, coughs,
etc.
Tetanus
Costridium tetani
Nerves
Contaminated
wounds
Tuberculosis
Mycobacterium tuberculosis
Lung,
bones
coughs
38
Some
bacteria
cause
diseases -Disease
causing
bacteria
are call
PATHOGENIC
39
Helicobacter
pylori
is the
pathogenic
bacteria
that can
causes ulcers
40
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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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.
43
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..
45
46
Here is a non-enveloped bacteria
virus inserting it’s DNA into a
bacterial cell.
47
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
49
All viruses have two main parts:
1. DNA or RNA – genetic info
2. Capsid – a protein encasement
50
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
51
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

52
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
56
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
57

Lysogenic Cycle
58
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


Emerging Viruses – exist in isolated
habitats


Ex.) chickenpox vaccine, AZT, Acyclovir,
protease inhibitors.
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.
60
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 (binary fission)
61

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
63

So… why not take out a plasmid, cut it
apart and add any other DNA piece that
we want!
64

Then put it back in the bacteria and
grow more bacteria with that new
plasmid that we have created! Hmmm?
http://www.learner.org/channel/courses/biology/archive/ani
mations.html
65


How could rDNA and transformation be
useful?
To be answered in DNA technology
presentations
66


Transduction – viruses attack cells
Bacteriophages: like tiny little syringes
that inject DNA into the cell
67
Look at how the virus infects
http://www.slic2.wsu.edu:82/hurlbert/mic
ro101/pages/Chap11.html
68
Viral Infections

Ebola?
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