Post on 05-Jan-2016
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BACTERIA
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Bacterial colony
Figure 4.1
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5Bacteria 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 compared to a white blood cell that is going to eat it
Bacteria
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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• Adapted to survive where no other organisms can.• Grouped based on:
– Structure, physiology, molecular 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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Kingdom Eubacteria
• Can have one of three basic shapes
1. Bacilli – rod-shaped2. Spirilla – spiral-shaped3. Cocci – sphere-shaped
Streptococci – in chains
Staphylococci – grape-like clusters
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Bacillus bacteria are rod shaped
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Coccus bacteria are
sphere shaped
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Spirillium bacteria have a corkscrew shape
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BACTERIA PICS
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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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Strepto- bacteria 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.
– can produce exotoxins made of protein
• Gram-negative do not retain stain and take second pink stain instead.
– can produce endotoxins made of lipids and carbohydrates
– Watch it happen! http://youtu.be/aJpZzF3h3kc
28No 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– Some are Thermophilic, Some prefer acidic envmt.
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These heterotrophi
c bacteria digest oil -- remember
oil is partially decayed plant and
animal cells
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BACTERIA REPRODUCES binary FISSION
First the chromosomal DNA makes a copyThe 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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CONJUGATION
Exchange DNA through Exchange DNA through Conjugation tube/pilusConjugation tube/pilus
http://youtu.be/EtxkcSGU698
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Transformation and Tranduction
• Transformation: Bacterial cell takes in DNA from external environment– http://youtu.be/eovTbQgan5M
• Transduction: Virus obtains DNA from Bacterial host
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Examples
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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
CHOLERA
DENTAL CARIES
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ROCKY MOUNTAIN Spotted Fever tickborne disease caused by the bacterium Rickettsia rickettsi
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LYME DISEASE
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SALMONELLA
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STREP THROAT
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TUBERCULOSIS