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An introduction to bacteriaAn introduction to bacteria
They Are EverywhereThey Are Everywhere
ProkaryotesProkaryotes ProkaryoteProkaryote: : Single-celledSingle-celled organism organism
that lacks a that lacks a true nucleustrue nucleus (also called (also called bacteriabacteria))
DNA is not surrounded by a DNA is not surrounded by a nuclear nuclear membranemembrane, have no membrane , have no membrane bound bound organelles.organelles.
Cover almost every Cover almost every
cmcm22 of earth! of earth!
Size MattersSize Matters Prokaryotes = 1-5 micrometersProkaryotes = 1-5 micrometers Eukaryotes = 10-100 micrometersEukaryotes = 10-100 micrometers
Vs.
Prokaryotic cells are much smaller than eukaryotic cells.
One to TwoOne to Two *Until recently all prokaryotes were *Until recently all prokaryotes were
one kingdom, Moneraone kingdom, Monera Monera is now split into 2 Monera is now split into 2 kingdomskingdoms:: Eubacteria, ArchaebacteriaEubacteria, Archaebacteria
Now three domains
1)Eubacteria/Bacteria
2)Archaea
3)Eukaryota/Eukarya
ArchaebacteriaArchaebacteria!!
A hot springs in Yellowstone National park!
ArchaeabacteriaArchaeabacteria
Lack Lack peptidoglycanpeptidoglycan walls and have walls and have different membrane lipids than different membrane lipids than EubacteriaEubacteria
DNA sequences are DNA sequences are closercloser to to Eukaryotes than BacteriaEukaryotes than Bacteria
ExtremoExtremophilesphiles – – ‘‘phileo’ in Greek means phileo’ in Greek means
lovelove Extremophiles:Extremophiles:– Live in extreme environments!Live in extreme environments!
HalophilicHalophilic: salt loving: salt loving
Thermophilic: Thermophilic: heat lovingheat loving
Methanogens – produce methane gas
Live in the gut of mammals,
sewage disposalplants and swamps
EubacteriaEubacteria Largest of prokaryote groupsLargest of prokaryote groups *Have cell walls that contain *Have cell walls that contain
peptidoglycanpeptidoglycan (carbohydrate) (carbohydrate) Find everywhere on earth.Find everywhere on earth.
ShapesShapes Three ShapesThree Shapes
1) Bacilli
(rod-shaped)
2) Cocci
(spherical)
3) Spirilla
(spiral or corkscrew)
“Strep” throat
ShapesShapes
SS S
SSSSSS S
Streptococci Streptobacilli Streptospirilla
Staphylococci Staphylobacilli Staphylospirilla
Form chains or strings
Form clumps like grapes
Rod shaped = Bacilli
Round = Cocci
Spiral shaped = spirilla
Cell WallsCell Walls Two Types of Eubacteria:Two Types of Eubacteria:
– Gram-PositiveGram-Positive ThickThick peptidoglycan walls peptidoglycan walls Turn Turn dark purpledark purple when stained when stained
– Gram-NegativeGram-Negative Much thinner walls inside an outer lipid layerMuch thinner walls inside an outer lipid layer Appear Appear pink or light redpink or light red
FlagellaRibosome
Pili
Cell membrane
DNA
Cytoplasm
Plasmid
Cell wall
Capsule
Pili - Help withconjugation – transferring of genetic material p.558,Stickto host’s cells
Flagella:Movement
Ribosomes- Makingproteins
DNA - Carries the genetic material
Cytoplasm - Contains DNA, Proteins and plasmid
Plasmid – piece of DNA , plays role during conjugation
Capsule – Protects against drying out, chemicals and host’s white blood cells.
Cell wall - Protects, givescell shapeEubacteria–has peptidoglycan
Cell membrane – Regulates the movement of materials in and out of the cell
Conjugation
Pili – forming conjugation bridge
EnergyEnergy
HeterotrophsHeterotrophs Parasitic – Cause diseases Parasitic – Cause diseases
(pathogens)(pathogens)
Saprophytic Saprophytic – Feed on dead tissues – Feed on dead tissues - Decomposers- Decomposers
AutotrophsAutotrophs
Photoautotrophs:Photoautotrophs: – Use light energy to convert COUse light energy to convert CO22 and H and H22O O
to food (like plants)to food (like plants)– Ex: Ex: cyanobacteriacyanobacteria
Chemoautotrophs:Chemoautotrophs:– Use Use chemicalchemical energy to convert CO energy to convert CO22
and Hand H22O to food O to food
Releasing EnergyReleasing Energy Obligate AerobesObligate Aerobes::
– Require constant supply of oxygenRequire constant supply of oxygen Obligate AnaerobesObligate Anaerobes::
– Do notDo not require oxygen . . . It kills them require oxygen . . . It kills them Facultative AnaerobesFacultative Anaerobes::
– Do not require oxygen, but can live with Do not require oxygen, but can live with itit
– Ex: E. coli Ex: E. coli
*Growth and Reproduction*Growth and Reproduction
Some bacteria can divide every 20 Some bacteria can divide every 20 minutesminutes– If there was unlimited resources 1 If there was unlimited resources 1
bacteria could grow into a mass 4000 bacteria could grow into a mass 4000 times the mass of earth in just 48 times the mass of earth in just 48 hours!!!hours!!!
ReproductionReproduction
Binary fission
1) Binary Fission1) Binary Fission Binary Fission: Binary Fission:
– Asexual reproduction where organism Asexual reproduction where organism replicates replicates DNA DNA and divides in halfand divides in half
– Produces two Produces two identical identical daughter cellsdaughter cells
2) 2) ConjugationConjugationConjugation: (“Sexual” reproduction)
A type of sexual reproduction where organism exchange genetic information
3. Forming Endospores
• Help survive unfavorable conditions.
Anthrax spores
Some are BAD and make us ill
StreptococcusStreptococcus
Strep throat
Pneumonia
Tetanus (lock jaw)Tetanus (lock jaw)
E. coliE. coli
Affects nervous system
Some in our intestines … others are
pathogens that can cause kidney
failure
BacteriaBacteriaCan be bad … but can be good
Make vitamins that Make vitamins that we cannot makewe cannot make
ourselvesourselves
DecomposersDecomposers *Help breakdown sewage treatment *Help breakdown sewage treatment
waterwater
Feel better with??
Nitrogen FixationNitrogen Fixation Converting nitrogen gas into a form Converting nitrogen gas into a form
plants can use (plants can use (nitrates – NOnitrates – NO33))– Allows nitrogen to cycle through Allows nitrogen to cycle through
biospherebiosphere
For example Rhizobium living in the roots of legumes such as soybean plants.
Other UsesOther Uses Oil digestion/Oil digestion/Clean up of pollutantsClean up of pollutants
(Bioremediation)(Bioremediation)
Are living:1. Made up of cells2. Have DNA3. Grow and develop4. Use energy5. Homeostasis6. Reproduction7. Respond to stimuli8. Evolve/Show adaptations – resistant
bacteria9. Show some type of organization – Flagella,
pili, ribosomes, cell wall
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