1. © 2014 Pearson Education, Inc. Prokayrotes & prokaryotic diversity  Common characteristics  Bacteria v Archaea  Structure  Genetics  Metabolism  Role in env.

2. © 2014 Pearson Education, Inc. Prokaryotic history  Oldest form of life—3.5 bil yrs  First forms anaerobic  Development of aerobic forms oxygenated the atmosphere  3.5 b.y. of divergence  incredible diversity  Most abundant organism on earth  Two groups: Bacteria & Archaea

3. © 2014 Pearson Education, Inc. Common Traits of Prokaryotes (Bacteria & Archaea)  Unicellular ..but….  Cell wall — not of cellulose or chitin  No membrane bound organelles  ….but…..  No nucleus  Single circular chromosome  Small  0.5 micrometers – 5 micrometers

4. © 2014 Pearson Education, Inc. Bacteria v. Archaea BacteriaArchaea Cell wallPeptidoglycanPolysaccarides+protein (no peptidoglycan) RNA Polymerase1 kindSeveral kinds Introns in DNANoYes Histone w/ DNANoyes ExtremophilicNoyes

5. © 2014 Pearson Education, Inc. Table 27.2

6. © 2014 Pearson Education, Inc. Figure 27.UN04 Fimbriae Cell wall Capsule Internal organization Flagella Circular chromosome Sex pilus

7. © 2014 Pearson Education, Inc. Structure & Diversity  Shape  Cell wall  Internal structure  DNA  motility 3 µm 1 µm

8. © 2014 Pearson Education, Inc. Structure & Diversity  Many shapes  Cocci (spheres)  Bacilli (rods)  Spirilla (spirals/helixs) Spherical Rod-shaped Spiral 3 µm 1 µm

9. © 2014 Pearson Education, Inc. Figure 27.3 (a) Gram-positive bacteriaGram-negative bacteria (b) Cell wall Peptido- glycan layer Plasma membrane Carbohydrate portion of lipopolysaccharide violet Cell wall Outer membrane Peptido- glycan layer Plasma membrane pink Cell Wall and Capsule  Cell wall of peptidoglycan  Gram –  Gram +  Capsule of polysaccharide or proteins

10. © 2014 Pearson Education, Inc. Endospores  Endospores are encapsulated DNA packets Coat Endospore

11. © 2014 Pearson Education, Inc. Motility  Flagella (different from Eukaryotic flagella)  Pili  Taxis = movement toward (+) or away from (-) stimuli

12. © 2014 Pearson Education, Inc. DNA Organization  Single circular chromosome  In nucleoid region  Plasmids: independently replicating loops of DNA

13. © 2014 Pearson Education, Inc. Reproduction  Binary fission=chromosome replicated, then cell divides  ASEXUAL = clones (except for mutations)

14. © 2014 Pearson Education, Inc. Genetic Diversity  Short generations + mutation  Genetic Recombination/horizontal gene transfer  Conjugation: DNA transfer (plasmids)  Transformation:  Transduction

15. © 2014 Pearson Education, Inc. Figure 27.13 Bacterial chromosome F plasmid F + cell (donor) Mating bridge Bacterial chromosome (a) Conjugation and transfer of an F plasmid F − cell (recipient) Sex pilus CONJUGATION

16. © 2014 Pearson Education, Inc. Figure 27.11-5 Phage infects bacterial donor cell with A + and B + alleles. Phage DNA is replicated and proteins synthesized. Fragment of DNA with A + allele is packaged within a phage capsid. Phage with A + allele infects bacterial recipient cell. Incorporation of phage DNA creates recombinant cell with genotype A + B −. A+A+ Donor cell Phage DNA A+A+ B+B+ A+A+ B+B+ A+A+ B−B− A−A− Crossing over Recombinant cell Recipient cell B−B− A+A+ 1 2 5 4 3 TRANSDUCTION

17. © 2014 Pearson Education, Inc. Transformation: Update of DNA in the environment by bacteria

18. © 2014 Pearson Education, Inc. Nutritional modes SOURCE OF ENERGY NUTRITIONAL MODESLight as energy sourceChemicals as energy source SOURCE OF CARBONCO2 (or related inorganic) PhotoautotrophChemoautotroph Organic compoundsPhotoheterotrophschemoheterotrophs Photoautotrophs = photosynthetic CO 2 + H 2 0  C 6 H 12 O 6 + O 2

19. © 2014 Pearson Education, Inc. Aerobic v. Anaerobic  Obligate Aerobes = require O2  Obligate Anaerobes = O2 is toxic  fermentation or anaerobic respiration in which substances other than O2 accept electron  Facultative Anaerobes:  Prefer to use O2, but don’t need it

20. © 2014 Pearson Education, Inc. Nitrogen Metabolism  some cyanobacteria and some archaea can fix nitrogen  N-fixing = N2  NH3  NH3 can be used as nitrogen source by other organism  Part of nitrogen cycle  All other organisms on earth depend on this in order to get N for proteins

21. © 2014 Pearson Education, Inc. Prokaryotic Cooperation  Filaments & colonies  Biofilms  Deep sea aggregates

22. © 2014 Pearson Education, Inc. Bacterial Diversity  Bacteria are currently organized into 5 non- monophyletic groups Proteobacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria

23. © 2014 Pearson Education, Inc. Figure 27.15 UNIVERSAL ANCESTOR Eukaryotes Korarchaeotes Euryarchaeotes Crenarchaeotes Nanoarchaeotes Proteobacteria Chlamydias Spirochetes Cyanobacteria Gram-positive bacteria Domain Eukarya Domain Archaea Domain Bacteria

24. © 2014 Pearson Education, Inc. Proteobacteria (5 major subunits)  Gram-  Aerobic & An_  All nut. Modes but photochem (which is archaean)  Incl nitrogen fixers (N cycle) & others involve w/ N-cycle  Sulfur metabolizers  Human pathogens: H pylori (ulcers), salmonella (food poisoning), Leginella (legionnaires disease), vibrio cholerae (cholera)

25. © 2014 Pearson Education, Inc. Chlamydias  Gram –  Can only survive w/in animal cells and depend on host cells for ATP  Cell walls lack peptidoglycan (have a liposaccharide instead which inhibits it from being phogocytized by host)  Includes human pathogens (Chlamidia STD, most common STD world wide)  Can’t be cultured and was once thought to be a virus

26. © 2014 Pearson Education, Inc. Spirochetes  Spiral, move by rotating w/ internalized flagella like structure  Free living and pathogenic forms (syphilis and lyme disease)

27. © 2014 Pearson Education, Inc. Figure 27.3 (a) Gram-positive bacteria Gram-negative bacteria (b) Cell wall Peptido- glycan layer Plasma membrane Carbohydrate portion of lipopolysaccharide Crystal violet is easily rinsed away, revealing the red safranin dye. Peptidoglycan traps crystal violet, which masks the safranin dye. Gram-positive bacteria Gram-negative bacteria Cell wall Outer membrane Peptido- glycan layer Plasma membrane 10 µm

28. © 2014 Pearson Education, Inc. Gram+ v. Gram- Gram-positive bacteria have simpler walls with a large amount of peptidoglycan Gram-negative bacteria have less peptidoglycan and an outer membrane that can be toxic

29. © 2014 Pearson Education, Inc. Figure 27.3c Gram-positive bacteria Gram-negative bacteria 10 µm

30. © 2014 Pearson Education, Inc. Figure 27.1

31. © 2014 Pearson Education, Inc. Table 27.1

32. © 2014 Pearson Education, Inc. Cyanobacteria  These are photoautotrophs that generate O 2  Plant chloroplasts likely evolved from cyanobacteria by the process of endosymbiosis Cyanobacteria Oscillatoria, a filamentous cyanobacterium 40 µm Photosynthetic cells Heterocyst 20 µm Anabaena

33. © 2014 Pearson Education, Inc. Gram-Positive Bacteria  Gram-positive bacteria include  Actinomycetes, which decompose soil  Bacillus anthracis, the cause of anthrax  Clostridium botulinum, the cause of botulism  Some Staphylococcus and Streptococcus, which can be pathogenic  Mycoplasms, the smallest known cells Gram-positive bacteria Streptomyces, the source of many antibiotics (SEM) 5 µm

34. © 2014 Pearson Education, Inc. Archaea  Archaea share certain traits with bacteria and other traits with eukaryotes  Some archaea live in extreme environments and are called extremophiles  Extreme halophiles live in highly saline environments  Extreme thermophiles thrive in very hot environments  Methanogens live in swamps and marshes and produce methane as a waste product  Methanogens are strict anaerobes and are poisoned by O 2  In recent years, genetic prospecting has revealed many new groups of archaea

35. © 2014 Pearson Education, Inc. Figure 27.17

36. © 2014 Pearson Education, Inc. Ecological Interactions  Symbiosis is an ecological relationship in which two species live in close contact: a larger host and smaller symbiont  Prokaryotes often form symbiotic relationships with larger organisms  In mutualism, both symbiotic organisms benefit  In commensalism, one organism benefits while neither harming nor helping the other in any significant way  In parasitism, an organism called a parasite harms but does not kill its host  Parasites that cause disease are called pathogens

37. © 2014 Pearson Education, Inc. Humans & Mutualistic Bacteria  Human intestines are home to about 500–1,000 species of bacteria  Many of these are mutualists and break down food that is undigested by our intestines Pathogenic Bacteria  Bacteria cause about half of all human diseases  Some bacterial diseases are transmitted by other species  Exotoxins are secreted and cause disease even if the prokaryotes that produce them are not present  Endotoxins are released only when bacteria die and their cell walls break down

38. © 2014 Pearson Education, Inc.  Prokaryotes are the principal agents in bioremediation, the use of organisms to remove pollutants from the environment  Bacteria can be engineered to produce vitamins, antibiotics, and hormones  Bacteria are also being engineered to produce ethanol from agricultural and municipal waste biomass, switchgrass, and corn