I. Prokaryote Domains: Archaea and BacteriaA. Evidence of early divergence

1. Archaea: are the “ancient” bacteria2. Bacteria (Eubacteria): are the “modern” bacteria3. Domain Eukarya: appears to have diverged from Archaea (after Bacteria)

- also possible that first eukaryote was fusion of Archaea and Bacteria

B. Differences between Archaea and BacteriaArchaea have as much in common with Eukaryotes as with Bacteria

II. Characteristics of ProkaryotesA. Shape

1. coccia. streptococcusb. staphylococcus

2. bacilli

3. spirala. vibrios (comma-shaped)b. spirilla (helical and short)c. spirochetes (longer and flexible)

B. Structure1. cell wall

a. maintains cell shape and provides protectionb. but may not prevent water lossc. may be encased in lipopolysaccharide membrane

- the lipids may cause toxicity

B. Structure1. cell wall

a. maintains cell shape and provides protectionb. but may not prevent water lossc. may be encased in lipopolysaccharide membrane

- the lipids may cause toxicityd. gram (-): has the membranee. gram (+): lacks the membrane

2. pilia. surface adhesionb. adhesion to other bacteriac. sex pili

- conjugation

3. circular DNA (single chromosome)- maybe plasmids also

4. flagella- simpler than eukaryotic ones

C. Reproduction1. binary fission

C. Reproduction1. binary fission2. conjugation

a. plasmid transferb. replicated and passed through sex pilusc. used to pass on useful traits

3. endospores- anthrax, botulism

D. Differences from eukaryotes1. no true internal compartmentalization (organelles)2. small size3. usually just unicellular

- sometimes cooperate metabolically

D. Differences from eukaryotes1. no true internal compartmentalization (organelles)2. small size3. usually just unicellular

- sometimes cooperate metabolically- biofilms (surface-coating colonies)

D. Differences from eukaryotes1. no true internal compartmentalization (organelles)2. small size3. usually just unicellular

- sometimes cooperate metabolically- biofilms (surface-coating colonies)

4. no rod-shaped chromosomes

D. Differences from eukaryotes (cont’d)5. binary fission vs. mitosis6. simpler flagella7. metabolic diversity

a. autotrophs - photoautotrophs (get C from air)- chemoautotrophs (also get C from air)

b. heterotrophs- photoheterotrophs (get C from organic compounds)- chemoheterotrophs (similar to animals)

III. Types of ProkaryotesA. Archaea

1. extreme halophiles- extreme salinity (5x’s that of seawater)

2. extreme thermophiles- even at or above boiling- thermoacidophiles

3. methanogens- anaerobic- swamp gas (bubbles up from mud)- cow gas

4. many also live in less harsh environments- ocean (especially deep)

B. Bacteria1. proteobacteria

a. large group containing gram(-) bacteriab. N2-fixersc. animal gut bacteria

2. chlamydias

- blindness- urethritis (STD)

3. spirochetes- syphilis

3. spirochetes- syphilis- Lyme disease

4. gram-positivesa. staph and strep (typically)b. many soil decomposersc. mycoplasmas

- 2 million pneumonias/year US

5. cyanobacteriaa. oxygen-producing photosynthesisb. major food source for aquatic/marine ecosystemsc. probably responsible for the initial production of O2 on earth

F. Diseases (Section 16.8)1. attack with white blood cells

F. Diseases 1. attack with white blood cells2. antibiotics

- resistant strains (13.15)

IV. Viruses

- not alive