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Bacteria=Prokaryotes
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Prokaryotes
No organelles except
ribosomes
NO NUCLEUS!
Eukaryotes
Lots of organelles
INCLUDING
NUCLEUS!
Bacterial Characteristics
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Oldest organisms:
3.5 billion yrs. old.
Live in almost every
environment.
Eubacteria
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Kingdom Eubacteria
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Common environments
Believed to be the ancestors of
mitochondria and chloroplasts--organelles in eukaryotic cells
Archaebacteria
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Kingdom Archaebacteria
 Found in extreme environments
 Ancient bacteria-gave rise to
eukaryotic cells
Characteristics-Size
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Size
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Red blood cell is 250X’s larger than a bacterium
1 gram of soil can contain 2.5 BILLION bacteria
Relative bacteria size
Characteristics-Shapes
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Shapes:
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Cocci-round
Bacilli-rod-shaped
Spirilla-spiral
Bacterial structure
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Interior structures
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Has DNA and cytoplasm—no nucleus or
other membrane bound organelles
EXCEPT ribosomes for protein synthesis!
Bacterial Structure
Bacterial structure
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Exterior structures
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Flagella--whip-like tail for locomotion
Cell membrane to control what goes in
and out
Cell wall for protection
2 Types of Cell Walls
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2 types of cell walls
found in bacteria
Identified as Gram +
or Gram There’s a chemical
difference b/t them.
Gram staining
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Special staining
process
“Gram positive is
purple; Gram
negative is not.”
2 Types of Cell Walls
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Gram +
 Thick cell wall
 Holds purple stain,
so cells look purple
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Gram
Two thin layers
make up cell wall
Doesn’t hold purple
stain so appears pink
2 Types of Cell Walls
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Treatment of illness due to
these bacteria is different!
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Gram - : generally NOT
affected by antibiotics
 i.e. E. coli
Gram +: affected by antibiotics
 i.e. S. pneumoniae
Bacterial Reproduction
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Binary fission
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Bacteria’s process
of reproduction
where 1 becomes 2.
Results in clones
1000’s of bacteria
that result from one
undergoing binary
fission is called a
colony
How are bacteria so diverse?
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They have several ways of exchanging genetic
information.
Conjugation--exchanging DNA through a straw-like
tube.
Transformation—another method of transferring
genes between bacteria.
Useful Bacteria
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Decomposers- Recycle nutrients such as CO2 ,
water, nitrogen, and phosphorus
Useful Bacteria
•Nitrogen fixation- soil bacteria
take nitrogen gas from the air (N2)
and change it into a useable form
that plants can absorb (NH3ammonia.)
•Plants use the nitrogen to produce
their proteins and DNA.
•Some bacteria are photosynthetic
and also provide oxygen
N2
Bacteria
NH3
YUMMY!
Useful Bacteria
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Food-- yogurt, olives, pickles, chocolate
Drugs -- insulin production
Clean up oil spills
Animal digestion and vitamins, including our
own
Microbe Discovery Movie
Harmful Bacteria
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Pathogen- Disease causing organisms.
Pathologists -scientists who study pathogens.
Not many bacteria are pathogenic— ONLY 1%!
Disease Transmission:
a.) Water
b.) Air
c.) Food
d.) Animals/Insects
e.) Human Contact
Bacterial Diseases
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Tuberculosis
Syphilis
Bubonic Plague
Typhus
Tetanus
Lyme Disease
Controlling Bacterial Growth
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What do bacteria require to live and
reproduce?
- Food, water, and the right climate.
-Give bacteria these things, and they grow;
remove them and they don’t.
Nutrition and Energy
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How do bacteria “eat”?
1.) Autotrophic- “self-feeders”
MAKE food
*Photosynthetic so they release oxygen!!!
HAVE NO ORGANELLES SO NO CHLOROPLASTS!!!
*Chemosynthetic
2.) Heterotrophic- “other-feeders”
GET food
*Consumers
*Decomposers
*Parasites
Growing Bacteria on Petri Dishes
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Plastic Petri dishes have a Jell-O like
substance called AGAR with nutrients and
water for bacteria to grow on.
Growth Curve
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When bacteria are grown on agar in a Petri dish,
their food and water supply (AGAR) is limited
They live through four phases of growth without
addition of more agar.
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Lag
Log
Stationary
Death
GROWTH CURVE
Controlling Growth
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Antibiotics
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Antibiotic resistance
Sanitizing--Antiseptics and Disinfectants
Freezing
Cooking
Pasteurizing
Dehydrating
Vaccination
Antibiotics
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Alexander Fleming
Mold on his Petri dish had a zone of inhibition
around it where bacteria didn’t grow.
Mold released the
antibiotic penicillin
Antibiotic=against life; any
BACTERIA
substance produced by a
microbe that slows the
growth of other microbes.
MOLD
Antibiotics
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2 ways antibiotics control
bacteria:
 Bacteriocidal- kill them
by blocking protein
synthesis
 Bacteriostatic- prevent
them from undergoing
binary fission (prevents
them from making new
cell walls.)
BACTERIA
Each paper disk has antibiotics on it.
Which antibiotic is more powerful?
Antibiotics
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Antibiotics are made by :
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fungus (mold)
other bacteria, the most common Streptomyces.
present day antibiotics are synthetic modifications
of naturally occurring ones.
Work on Gram + bacteria
Antibiotic Resistance Movie
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Antibiotic resistant bacteria are not affected by
certain antibiotics!
Can be resistant due to:
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Special cell walls (i.e. Gram – bacteria) OR
Special antibiotic resistant genes
Don’t finish antibiotics:
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Weaker bacteria destroyed.
**Resistant bacteria still live and pass on resistant
genes through binary fission, conjugation and
transformation
Conjugation
Sanitizing
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Antiseptics---Chemicals used to inhibit
growth of bacteria on living tissues
Sanitizing
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Disinfectants—Chemicals used to inhibit
growth of bacteria on NON-living things.
Freezing
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How would this
control the
growth of
bacteria?
Would freezing
kill all the
bacteria?
Cooking
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Cooking can control
bacterial growth and
kill most bacteria if
heated to certain
temps—165F or hotter.
Use a meat
thermometer
Wash hands after
handling raw meat
Pasteurizing
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Using heat to kill
bacteria in liquids.
Dehydrating
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How would this control the growth of
bacteria?
Vaccination
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Prevents you from getting the disease. DOES NOT
CURE YOU.
Fast and strong immune system memory cells
produced which provides immunity just like if you
got the disease (i.e. chicken pox.)
Vaccination
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Can use weakened (attenuated) bacteria or viruses
MOSTLY use parts of bacteria or viruses—
acellular
Vaccine video
Structure of a Virus
Virus: a microscopic particle that invades and takes over cells
Relative virus size
100% of viruses are pathogenic!!!!
Structure of a Virus (cont.)
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Made of:
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nucleic acid (DNA or RNA)
surrounded by a protein coating (capsid).
Viral Replication
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Parasites (dependent on host for replication)
Steps of viral replication:
1.) Recognition of marker protein on specific cell
types.
2.) Attachment
3.) Injection (of nucleic acid)
4.) Assembly
5.) Lysis (cell bursting)
Characteristics of Living Things
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Homeostasis: stable internal conditions
Metabolism: use energy
Reproduction
Made of cells
Genetic material
VIRUSES ARE NOT LIVING THINGS!
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*****No metabolism, homeostasis, reproduction,
or cells
Replication Cycles of Viruses:
2 Types
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Viruses have either a lysogenic or lytic
replication cycle:
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Lytic: virus genetic material used quickly to take
over cell, then lysis occurs to release newly made
viruses.
Influenza and Ebola
Lytic Viruses
Lysogenic Viruses
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Lysogenic: virus nucleic acid “fuses” with the
host cell’s until lysis (bursting) LATER.
When infected cell undergoes cell cycle:
 replication of virus DNA with cell DNA
 many cells infected
During this “dormant” period no illness is seen
HIV and herpes
Lysogenic Virus
Protection Against Viruses
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ANTIBIOTICS DON’T WORK ON VIRUSES!!!
Vaccines:
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Used as PREVENTION, NOT A CURE!
Only useful against viruses that do not mutate and evolve
(change) rapidly.
HIV, common cold viruses and flu virus- DNA mutates
rapidly. No permanent vaccine!
Tamiflu is an antiviral medicine, but not reliable.
HIV
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Devastating Africa
30 million + people have the disease
Infects T cells of immune system
Can lie dormant in our DNA for 10 years +
Ryan White
HIV Dormancy
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During dormancy, people look healthy, but can still
spread the disease by:
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Sexual contact (including oral)
Sharing needles
Blood transfusions
Organ transplant
Baby to mother
Blood to blood contact of any kind
HIV video clip
Other Viral Diseases
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HIV
Common cold
Chicken pox
Measles
Rabies
Rubella
Mumps
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Influenza (flu)
Small pox
Hepatitis
Yellow fever
Ebola