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