1. Archaebacteria and Eubacteria
Chapter 18.2

2. Kingdom Archaebacteria (extremophiles)
Organisms in these two kingdoms are prokaryotes  have no membrane bound organelles
Kingdom Archaebacteria (extremophiles)
Usually live where there is no oxygen (anaerobic)
3 types
Methane-producing  live in swamps and cows stomachs
Salt-loving  live in lakes with a high mineral content
Acid and Heat-loving  live around deep ocean vents with temps above 100 OC

3. Kingdom Eubacteria (true bacteria)
Heterotrophic  use organic molecules as a food source
Some are parasites obtaining nutrition from living organisms
Some are saprophytes obtaining nutrition from dead organisms and organic waste (poop)
Photosynthetic autotroph  cyanobacteria
Produce chemical energy through photosynthesis
Chemosynthetic autotroph
Break down and release energy from compounds containing sulfur or nitrogen
Called chemosynthesis

4. General Structure of a Bacterium
Contain very small ribosomes
Single circular chromosome
Cell wall  prevents bacteria from bursting
Capsule  a sticky gelatinous layer outside of the cell wall
Flagellum  a whip-like projection that help the bacterium move
Pilus  air-like structures coming out the cell surface, help bacteria stick to surfaces
Plasmid  a few genes in a circular chromosome

5. Life of a Bacterium
Most bacteria live in an environment where there is more water outside than inside so water is always trying to get in
As long as the cell wall is intact, bacteria will still survive
Antibiotics and plain old soap cause holes to develop in the cell wall causing the bacteria to burst (die)

6. Gram stain  shows differences in cell wall structure
Identifying bacteria
Gram stain  shows differences in cell wall structure
Gram positive  stain purple
Gram negative  stain pink
Shape
Cocci  sphere
Bacillus  rod
Spirilli  spiral
Growth patterns
Diplo  pairs
Staphylo  grape-like clusters
Strepto  long chain

7. Reproduction
Binary fission  a form of asexual reproduction that produces identical offspring
Some bacteria can reproduce every 20 minutes in ideal conditions
Conjugation  a form of sexual reproduction where on bacteria transfers it chromosome to another through a pilus
Creates genetic diversity
Bacterial diversity
Metabolism
Obligate aerobes  require oxygen to respire
Obligate anaerobes  die in the presence of oxygen
Survival
Some bacteria form a tough outer layer called an endospore that allows them to survive when water is scarce

8. How are bacteria helpful and harmful?
Some bacteria fix nitrogen into a form that plants can use
Recycle nutrients
Used to make food and medicine
Cheese, yogurt, some antibiotics
Can cause disease
Anthrax, tuberculosis, cavities, strep throat