1. Biology 121: Diversity, Structure and Function Fall 2010 Sonoma State University Tom Buckley 08 Sep 10 Prokaryote diversity and metabolism

2. Prokaryotes: 90% of all biomass on Earth

3. Two major groups: Bacteria and Archaea Prokaryotic phylogeny Archaea extremophiles diverse metabolism Bacteria familiar prokaryotes many pathogens

4. Prokaryotic cells 0.5 - 5  m diameter Staphylococcus (strep throat) Escherichia coli (E. coli) Borellia burgdorferi (lyme disease) examples Q: what is 1  m in terms of millimeters?

5. Prokaryotic cell surfaces Bacteria: two groups Gram-positiveGram-negative: double membrane Archaea: no peptidoglycan 'Gram stain' stains peptidoglycan

6. Prokaryotic cell surfaces capsule: sticky polysaccharides Streptococcustonsil tissue protects against phagocytosis & detergents phago- = eat cyto = cell

7. Internal structure (Heterotrophic)(Autotrophic)

8. Prokaryotic DNA Much less DNA than eukaryotes Organised in circular chromosomes one very large loop + numerous very small ones (plasmids)

9. Plasmids in biotechnology Cut plasmid with restriction enzyme Add DNA fragment w/ new gene Plasmid recombines w/ fragment Infect plant cells w/ bacterium Q: which plant cells should you infect?

10. Prokaryotic reproduction Binary fission identical copy Conjugation: one-way DNA transfer

11. Prokaryotic reproduction Fission every 20 min - 24 hours How long would it take to produce enough bacteria to reach the sun? bacterium:2  m long fission rate:every 3 hours sun distance:150 million km

12. Prokaryotic reproduction Short generation times Frequent mutation Huge population sizes Strong selection Extremely fast evolution

13. Prokaryotic evolution: example grew bacteria in low-glucose solutions periodically compare fitness against ancestral population RESULT

14. Prokaryotic evolution: example grew bacteria in low-glucose solutions periodically compare fitness against ancestral population Possible interpretation... ancestral population also evolved Control to rule this out... RESULT answer in class something else in the solution favoured the new population answer in class

15. Metabolism

17. Food = electron donor NADH = electron carrier O 2 = electron acceptor

18. Metabolism Aerobic respiration CO 2 CH 2 O ATP ADP energy electrons O2O2 H2OH2O oxidation ATP ADP

19. Metabolism Food = electron donor NADH = electron carrier O 2 = electron acceptor

20. Aerobic respirationAnaerobic respiration CH 2 O ATP ADP energy O2O2 H2OH2O lactate or ethanol + CO 2 CO 2 CH 2 O ATP ADP energy electrons O2O2 H2OH2O ATP ADP x oxidation ATP ADP

21. Aerobic respirationPhotosynthesis CO 2 CH 2 O oxidation ATP ADP energy electrons O2O2 H2OH2O ATP ADP CO 2 CH 2 O reduction solar energy electrons O2O2 H2OH2O ATP ADP

22. Aerobic respirationPhotosynthesis CO 2 CH 2 O oxidation ATP ADP O2O2 H2OH2O CO 2 CH 2 O reduction O2O2 H2OH2O

23. Prokaryotic metabolism: diversity

24. Prokaryotic metabolism: ecology 1. Nitrogen fixation NH 3 organic N N2N2 1 2. Ammonification organic NNH 3 2 NO 3 3. Nitrification 3 4. Denitrification NO x 4 4

25. Nitrogen fixation (requires anaerobic conditions) Prokaryotic metabolism O2O2 N

26. Nitrogen fixation (some plants) Prokaryotic metabolism: symbiosis Gut digestion (many animals, incl. ruminants & humans) legume family (beans) many others nodules

27. Prokaryotic metabolism: ecology 1. Nitrogen fixation NO 3 3. Nitrification 4. Denitrification NO x NH 3 organic N N2N2 1 2. Ammonification organic NNH 3 2 3 4 4 Q: What would happen to atmospheric N 2 without N-fixing prokaryotes?

28. Prokaryotic metabolism: ecology 1. decomposition CO 2 organic C 1 Q: What would happen to atmospheric CO 2 without decomposing prokaryotes? 2. photosynthesis 3. death/senescence 2 3

29. Biotech Prokaryotes: relevance to humans Gut digestion Pathogens Ecology & agriculture: decomposition (C & N cycling) bioremediation (many pollutants) synthetics (plastics, ethanol) rapid evolution --> antibiotic resistance