1. Bacteria

2. What is Bacteria? Prokaryotes – no nucleus
Eubacteria: peptidoglycan in cell wall
Live almost everywhere
Archaebacteria: lack peptidoglycan
DNA is more similar to eukaryotes; possible ancestors of eukaryotes
extremely harsh environments

3. Identifying Prokaryotes
Shape
bacilli – rod shape
cocci – spherical
spirilla – spiral and corkscrew-shaped

4. Identifying Prokaryotes
Cell Wall
Gram staining - identifies peptidoglycan in the cell wall
Gram positive – thick peptidoglycan walls – purple
Gram negative – thinner walls – red

5. Identifying Prokaryotes
Movement
no movement
Flagella – whip-like structure
Glide on slime-like material

6. Identifying Prokaryotes
Metabolic Diversity
Obligate aerobes: requires oxygen
Obligate anaerobes: absences of oxygen
Facultative anaerobes – can live with or without oxygen

7. Growth and Reproduction
Binary Fission – copy DNA and divide in half
Conjugation – a hollow bridge forms between two bacterial cells to exchange genes
Spore Formation: unfavorable conditions i.e. endospore
spores can remain dormant for months to years
when conditions improve, endospore germinates and bacterium begins to grow

8. Importance of Bacteria
recycle nutrients
sewage treatment
nitrogen fixation
digest petroleum - oil spills
remove waste products and poisons from water
synthesize drugs