1. Describing Prokaryotes handout

2. prokaryotic vs. eukaryotic cells

3. Describing Prokaryotes 1.Phylogeny Comparison of conserved genes (16S rRNA) Can group to species or sometimes sub- species level Does not always predict function or metabolic capabilities (phylogeny ≠ function)

4. Describing Prokaryotes 1.Phylogeny 2.Physiology/Metabolism –Source of C –Source of energy –Electron acceptors

5. Electron Acceptors Internal and Organic = Oxygen = NO 3 -, Fe(III), SO 4 2-, CO 2 =

6. How organotrophs and lithotrophs make energy Thermodynamics Oxidation/Reducti on couples More Oxidized More willing to take up electrons More reduced More able to give up electrons

7. Autotrophy – use CO 2 as C –Phototrophy Oxygenic – produces O 2 (electrons come from H 2 O) Anoxygenic – no O 2 production –Electron donor »H 2 »H 2 S, S o »Organic C »Fe 2+ –Lithotrophy – use inorganic chemical as energy Energy source –H 2 –HS -,S o,S 2 O 3 2- –NH 4, NO 3- –Fe 2+ –Mn 2+

8. Heterotrophy – use organic C as C source Fermentation Aerobic respiration –Electron Acceptor »O 2 Facultative –Electron acceptor »Use O 2 when available »Use fermentation or NO 3 - when no O 2 Anaerobic respiration –Electron Acceptors »NO 3-, NO 2- »S o, S 2 O 3 2-, SO 3 2-, SO 4 2- »Fe 3+, Mn 4+ »CO 2 »Fumarate (organic C)

9. Describing Prokaryotes 1.Phylogeny 2.Physiology/Metabolism 3.Form & Structures Cell wall - Gram positive, Gram negative, Acid-fast Endospores producing Filamentous, motility, colony morphology…

10. Describing Prokaryotes 1.Phylogeny 2.Physiology/Metabolism 3.Form & Structures 4.Habitat Temperature pH Pressure Nutrient availability Salinity

11. Describing Prokaryotes 1.Phylogeny 2.Physiology/Metabolism 3.Form & Structures 4.Habitat 5.Other functions/processes N 2 fixation Antibiotic production pathogens

12. Examples Escherichia coli Methanococcus (lives in cattle gut, produce methane) Thiobacillus - example reaction H 2 S +O 2  SO 4 2- + 2H + Geobacter metallireducens – acetate - + 8Fe 3+ + 4H 2 O  2HCO 3 - + 8Fe 2+ + 9H +