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BacteriaBacteria
BacteriaBacteria Microscopic organisms that are Microscopic organisms that are
prokaryotesprokaryotes Make up two kingdoms of the Make up two kingdoms of the
classification system:classification system:– EubacteriaEubacteria– ArchaebacteriaArchaebacteria
First organism on earthFirst organism on earth Highly evolved and very diverseHighly evolved and very diverse
Structure of a BacteriaStructure of a Bacteria
ChromosomesChromosomes CapsuleCapsule RibosomesRibosomes Cell WallCell Wall Plasma MembranePlasma Membrane Flagella - movementFlagella - movement Pili - attachmentPili - attachment
EubacteriaEubacteria
The most common type of The most common type of bacteriabacteria
Found almost everywhere Found almost everywhere except extreme environmentsexcept extreme environments
Strong cell walls made of Strong cell walls made of peptidoglycanpeptidoglycan
Some have two cell wallsSome have two cell walls
ArchaebacteriaArchaebacteria
Found in extreme environmentsFound in extreme environments Thermoacidophiles: found in Thermoacidophiles: found in
hot, acidic environmentshot, acidic environments Halophiles: found in very salty Halophiles: found in very salty
environmentsenvironments Methanogens: cannot live in the Methanogens: cannot live in the
presence of oxygenpresence of oxygen
Bacteria ShapesBacteria Shapes
There are three different There are three different shapes of bacteria:shapes of bacteria:– Cocci (round)Cocci (round)– Bacilli (rod-shaped)Bacilli (rod-shaped)– Spirilli (spiral-shaped)Spirilli (spiral-shaped)
CocciCocci
BacilliBacilli
SpirilliSpirilli
Reproduction Reproduction
Most reproduce by binary fissionMost reproduce by binary fission– The cell divides into two The cell divides into two
daughter cellsdaughter cells– The single chromosome is also The single chromosome is also
duplicatedduplicated
Reproduction Reproduction (Continued)(Continued)
Certain bacteria undergo Certain bacteria undergo conjugationconjugation– Genetic information is Genetic information is
transferred from one cell to transferred from one cell to anotheranother
– New gene combinations are New gene combinations are formedformed
SurvivalSurvival
Certain bacteria may undergo Certain bacteria may undergo Spore Formation to help survive in Spore Formation to help survive in harsh environmental conditionsharsh environmental conditions– An endospore contains DNA and An endospore contains DNA and
some cytoplasmsome cytoplasm– Remains dormant for months or Remains dormant for months or
years years – Anthrax, botulism, tetanusAnthrax, botulism, tetanus
Special Types of Special Types of BacteriaBacteria
PhotoautotrophsPhotoautotrophs ChemoautotrophsChemoautotrophs AerobesAerobes AnaerobesAnaerobes Facultative AnaerobesFacultative Anaerobes
Harmful vs. Helpful Harmful vs. Helpful BacteriaBacteria
Some bacteria are Some bacteria are beneficialbeneficial
Others are harmfulOthers are harmful Micro-viewer labMicro-viewer lab
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