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Slide 1 of 40Most numerous organisms on Earth
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“ Most Wanted and Least Wanted Posters
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BACTERIA:•Most numerous organisms on Earth•1st forms of life on Earth•All are prokaryotic
•General Traits of all prokaryotes:•Lack a nucleus and membrane bound organelles.•Unicellular (separate or in a colony)•Can be autotrophic or heterotrophic•Are microscopic
•300 side by side = printed period
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Bacteri is found EVERYWHERE…
fFood
Air
Soil
On and in our body
On all objects
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430,000 year old bacteria found in a fresh water lake in Antarctica
Deep Ocean
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Some bacteria are:
1. Aerobic-requires oxygen
2. Anaerobic-lives in the absence of oxygen
Example:-Clostridium botulinum-Causes botulism / food poison -found improperly canned foods, meat and shell fish
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Cell wall: -made up of Peptidoglygcan(protein/carb combo) -protects and gives shape to cell.
-antibiotics inhibit bacteria from forming cell walls so future bacteria can be destroyed by your immune system
Cell wall
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Cell Wall
Cell membraneCell membrane:
-regulates what goes into and out of the cell -contains enzymes that aid in all cellular reactions
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Outer covering that is sticky. Allows bacteria to adhere to surfaces and prevents WBC’s from engulfing them.
Capsule
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Capsule
Cytoplasm
Cytoplasm:-liquid
solution which suspends DNA and ribosomes
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Capsule
Cytoplasm
Ribosomes
Ribosomes:
-uses DNA’sinstructions to
make all proteins
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Capsule
Cytoplasm
Ribosomes
DNA
DNA: -genetic material -1 loop of DNA
-known as the nucleoid
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Plasmid: -found in some bacteria -small loops of DNA -code for extra but not essential traits.
Ex/ antibiotic resistence
Capsule
Cytoplasm
Ribosomes
DNA
Plasmid
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Capsule
Cytoplasm
Ribosomes
DNA
Plasmid
Sex pili
Sex pili:
-short proteins which bacteria use to pick up plasmids from environment or from another bacteria cell
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Capsule
Cytoplasm
Ribosomes
DNA
Plasmid
Sex piliFlagella
Flagella: -1 or more longwhip like tails used for movement.
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Movement
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Classifying Prokaryotes
E. coli, a Typical Eubacterium
Cell wall
Cell Membrane
Ribosomes
PiliDNAFlagellum
Capsule
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Endospores
Form when a bacterium produces a thick internal wall that encloses its DNA and some of its cytoplasm during unfavorable growth conditions.
Spores can remain dormant for months or years.
Spores allow bacteria to survive harsh conditions. (extreme heat, lack of moisture, etc…)
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Ideal Reproductive/Growth Conditions
-moisture-warmth-food source-darkness
Food and moistureWarm and darkness
Ideal warm, dark and moist environment with plenty of food?
The human body
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Bacteria can be:
1. Heterotrophic-uses other organisms as a food source.
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2. Saprophytic:
-live off dead matter-bacteria is the #1 decomposer
3. Autotrophic:
-makes their own food through photosynthesis.
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Reproduction
Binary fission
Binary Fission Bacteria copies its DNA and divides in half, producing two identical daughter cells.
Form of asexual reproduction
Takes about 20 min. in bacteria.
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Conjugation
During conjugation, a hollow bridge made up of the sex pili forms between two bacterial cells, and genes move from one cell to the other.
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Transformation:
When bacteria use their sex pili to pick up DNA from their environment.
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The GOOD……..
To make medicines
Oil eating bacteria
To make food
#1 decomposer
Sewage treatment
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The BAD………..Makes us
sick/causes illnesses
STD’s: Gonorrhea, SyphilisChlamydia, Botulism, LymesDisease, Pinkeye, Tuberculosis, Pneumonia
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Can they be stopped?
RefrigerationFreezing
Heat: canning, cooking, sterilization
Dehydration
Antiseptics
Antibiotics
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You go to the doctors with a sore throat……………..now what happens????
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The doctor has to classify the bacteria to know how to
treat it.
1. The doctor cultures/grows the bacteria.
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Identifying Prokaryotes
2. The doctor determines the shape of the bacteria.
Bacilli
Rod-shaped prokaryotes are called
bacilli.
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Identifying Prokaryotes
Spherical prokaryotes are called cocci.
Cocci
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Identifying Prokaryotes
Spiral and corkscrew-shaped
prokaryotes are called spirilla.
Spirilla
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3.
Thedoctor determinesthecolony formation:
Strept mean grows in a long chain.
Staph means grows in a cluster
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Can you identify these bacteria?
Steptococcus
Staphococcus
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4. The doctor stains the bacteria.
Two different types of cell walls are found in Eubacteria. A method called gram staining tells them apart.
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Gram-positive bacteria have thick cell walls with large amounts of peptidoglycan.
-stains purple-produces exotoxins
-released during life of bacteria
Gram-negative bacteria have thinner cell walls inside an outer lipid layer.
-stains pink-produces endotoxins
-released after bacteria dies
Each type treated with different antibiotics
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