Bacteria
CHAPTER 19 470-477
Classifying Prokaryotes
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Divided into two different groups:
1.
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2.
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Eubacteria
Larger of the 2 domains
Live almost everywhere
Cell wall contain peptidoglycan
Archaebacteria
Lack peptidoglycan and have different membrane lipids
DNA are more like eukaryotes than eubacteria
Live in extremely harsh environments
Identifying Prokaryotes
 Prokaryotes are identified by characteristics such as
shape, the chemical nature of their cell walls, the way
they move, and the way they obtain energy.
 Shapes: Bacilli, cocci, and spirilla
Identifying Prokaryotes
 Cell Walls—Gram staining method is used to
identify the two different types of cell walls in
eubacteria. One stain is violet and the other red.
 Movement—identified by whether they move and
how they move.
Some prokaryotes do not move at all
 Some are propelled by flagella
 Others lash, snake, or spiral forward
 Others glide along on a layer of slimelike material they
secrete.
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Metabolic Diversity
 Best illustrates the diversity of bacteria.
 Ways in which they obtain energy
Heterotrophs—Obtain energy from foods they
consume
1.
Chemoheterotrophs—must take in organic molecules for
both energy and a supply of carbon
1.
1.
2.
Most animals, including humans, are chemoheterotrophs
Photoheterotrophs—these organisms are photosynthetic but
they need to take in organic compounds as a carbon source.
Metabolic Diversity
2. Autotrophs—are able to produce their own
energy/food
Photoautotrophs—use sunlight energy to
convert CO2 and H2O to carbon
compounds and oxygen
1.
1.
2.
Found where light is plentiful
Ex. cyanobacteria
Chemoautotrophs—make organic compounds from carbon
dioxide but do not require light as a
source of energy.
2.
1.
Instead they use energy directly from
chemical reactions involving ammonia,
hydrogen sulfide, nitrites, sulfur, or iron.
Growth and Reproduction
 When conditions are favorable, bacteria can grow and
divide at astonishing rates.
 If unlimited space and food were available and if all of its
offspring divided every 20 minutes, in just 48 hours they
would reach a mass 4000 times the mass of the Earth.
 Types of reproduction:
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1. Binary Fission
2. Conjugation
3. Spore Formation
Importance of Bacteria
 Bacteria are vital to maintaining the living world. Some are
producers that capture energy by photosynthesis. Others
are decomposers that break down the nutrients in dead
matter and the atmosphere. Still other bacteria have
human uses.
 Decomposers—bacteria help the
ecosystem recycle nutrients,
therefore maintaining
equilibrium in the environment
Importance of Bacteria
 Nitrogen Fixers—plants and animals depend on
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bacteria for nitrogen.
Plants need nitrogen to make amino acids, the
building blocks of proteins
Nitrogen fixers convert nitrogen gas from the
atmosphere into ammonia or other nitrogen
compounds
Human Uses—Clean-up (oil spills,
poisons from water, etc.), mining,
synthesis of drugs and chemicals.
E. coli—bacteria in our intestines
that aid in digestion.
Picture Credits
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http://www.attendconference.com/blog/wp-content/uploads/2011/10/bacteria-1.jpg
http://1.bp.blogspot.com/_qCM0lypaRCg/SxPysM4f34I/AAAAAAAAASA/AnzWCeU3i0
E/s1600/Rain+bacteria.jpg
http://meyerbio1b.wikispaces.com/file/view/eubacteria.jpg/58121302/eubacteria.jpg
http://www.encyclopedia.com/topic/Archaebacteria.aspx
http://www.answersingenesis.org/assets/images/articles/am/v2/n3/bacilli.jpg
http://kentsimmons.uwinnipeg.ca/16cm05/1116/27-03a-SphericalProkaryotes.jpg
http://www.pelletlab.com/v5Files/pellet/177362/Bacteria_spirillum.jpg
http://www.technovelgy.com/graphics/content06/micromotor-flagella.jpg
http://sciences.aum.edu/bi/bi2033/thomson/images/olih023p.gif
http://sharonapbio-taxonomy.wikispaces.com/file/view/27-x1ProkaryoteConjugation.jpg/50758483/27-x1-ProkaryoteConjugation.jpg
http://www.bigsiteofamazingfacts.com/wp-content/uploads/2010/04/salmonella.jpg
http://www.litzsinger.org/weblog/archives/email%20FallenTrunk3%20LREC%2010140
5.jpg
http://cotswoldgrassseeds.com/Articles/images/root_nodules.jpg
http://protist.i.hosei.ac.jp/pdb/images/Prokaryotes/Cyanobacteria/Cyanobacteria3.jpg
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http://leavingbio.net/BACTERIA%20Page_files/image018.jpg
http://www.emc.maricopa.edu/faculty/farabee/biobk/84150f.jpg
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