Archaebacteria and Eubacteria

1. Archaebacteria and Eubacteria Chapter 18.2

2. 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. 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