Archaebacteria and Eubacteria Chapter 18.2

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

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

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

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)

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

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

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