1. Prokaryotic profiles

2. When did prokaryotes first appear?

3. What are the basic differences? CharacteristicProkaryotesEukaryotes # of cellsUnicellularUni or multi DNA shapeDNA is circular, no histones DNA in chromosomes w/histones DNA locationFree in cellIn PM-bound nucleus True organelles?NoYes Ribosomes70S80S First amino acid in protein FormylmethionineMethionine Cell wall?Yes-peptidoglycanNo (animalia); Yes (plantae— cellulose); Fungi (chitin) ReproductionBinary fission three ways to reproduce three ways to reproduce Mitosis

4. How do prokaryotes compare in size with other microorganisms?

5. How do I describe their shapes?

6. Is a species always the same shape? Generally, yes –Monomorphic –however, environment can alter Some are pleiomorphic Photo from: uhavax.hartford.edu/bugl/Yersinia-pestis.jpg

7. The parts Starting from the outside and working inward

8. What’s outside the cell wall? Glycocalyx –Carbohydrates and/or peptides –Viscous –Can protect bacterium –Some help cells attach Teeth: Streptococcus mutans Capsule –Organized –Firmly attached to cell wall Slime layer –Unorganized –Loosely attached

9. What are flagella? Singular = __________ Monotrichous Amphitrichous Lophotrichous Peritrichous

10. What do flagella do? Run and tumble Swarming Allow for taxis –Chemotaxis –Phototaxis dancing bacteria!

11. What are axial filaments? AKA periplasmic flagella –Fibril bundles that spiral around cell

12. What’s the difference between fimbriae and pili? Found primarily on gram-negative bacteria For attachment, not movement Pilin protein Fimbriae (fimbria, singular) –Attachment E.g. to mucosal membranes Pili (pilus, singular) –For DNA exchange only

13. What’s in the cell wall? Peptidoglycan (PPG) –AKA murein –NAG-NAM disaccharide NAG = N- acetyleglucosamine NAM = N- acetylemuramic acid –Lysozyme disrupts NAG-NAM bond If lysis doesn’t occur, cell is called a protoplast –Linked with tetrapeptide Penicillin disrupts  lysis penicillin killing cells

14. What’s in the cell wall? Gram positive bacteria –Many PPG layers –Teichoic acids Different types Used for antigenic specificity tests

15. What’s in the cell wall? Gram negative bacteria –One or few PPG layer(s) –Outer membrane: lipopolysaccharides (LPS), lipoproteins, phospholipids Periplasm separates LPS from the PM (PPG is in periplasm) Provides barrier to some antibiotics, digestive enzymes Porins allow for access into cell –LPS used for specific antigen tests to I.D. species

16. What does a side-by-side comparison look like?

17. More comparison

18. How does this relate to gram staining? Hint: What does the LPS layer covering the gram negative cell do to it?

19. What are atypical cell walls? Mycoplasma –Smallest known independent bacteria –No cell walls –Often mistaken for viruses –PM has sterols to prevent lysis Mycobacteria –Mycolic acid in cell wall Hydrophobic Acid-fast stain identifies Tuberculosis, leprosy Archaea –Some have cell walls but not with PPG –Pseudo-murein Mycoplasm pneumoniae

20. What happens if the cell wall is damaged? Lysozyme lyses gram positive, but usually does not harm gram negative to the same extent –Why? Protoplast: gram positive Spheroplast: gram negative Osmostic lysis –If placed in a hypotonic environment

21. What’s inside the cell wall? Plasma membrane –Phospholipid bilayer –Fluid mosaic theory Segregates DNA during binary fission Secretes enzymes to make PPG, teichoic acid ATP production Selective permeable membrane… –Active vs. passive transport

22. What kinds of passive transport exist? Simple diffusion –For small, lipid-soluble substances Osmosis –Water movement via diffusion –Happens whenever difference in concentration across PM –Note: water often moves because solutes can’t Because PM is only semi- permeable Simple diffusion

23. What do you think will happen? A.Left side increases with water B.Right side increases with water C.No net movement of water Click here to show what actually happens: answer animation answer 

24. What is osmosis? Water concentration depends on number of solutes in it –Hypertonic –Isotonic –Hypotonic Water moves down its concentration gradient until osmolarity is equal

25. What do you think will happen? 10% glucose 20% glucose Distilled water 10% glucose For each, choose from A. No net changeB. cell swellsC. cell shrinks

26. What is facilitated passive diffusion? Protein- assisted diffusion –Transporters or carriers Amino acids, glucose –Channels (AKA “pores”) Most are gated (usually closed)

27. What is active transport? Movement of solute against gradient –Can you think of examples of where this might happen in your body? Requires energy b/c moving against gradient –From ATP Proteins sometimes called “pumps”

28. What is group translocation? Type of active transport –Only in prokaryotes –Chemically altered as it is pulled across PM into cell Once inside, cannot exit E.g. glucose phosphorylation Animation

29. What is the cytoplasm? Eukaryotes –Cytosol + organelles Prokaryotes: all stuff inside cell –80% water + nuclear area, ribosomes, inclusions (storage areas)

30. What is the nuclear area? AKA nucleoid Circular, double- stranded DNA –Called bacterial chromosome Plasmid –Also double-stranded DNA –Independent replication –Associated with PM proteins –Can gain or lose without killing cell –Can provide resistance to antibiotics, etc.

31. What are ribosomes? Manufacture proteins Two subunits –Each with proteins and rRNA –70S ribosomes (smaller than eukaryotes) 50S and 30S subunits Eukaryotes = 80S ribosomes (60S + 40S)

32. What are inclusions? Storage areas Metachromatic granules –Collectively called volutin Phosphate reserve for making ATP Polysaccharide granules –Iodine stain shows these Others with –Lipids, sulfur granules, etc. –Magnetosomes: iron oxide

33. What are endospores? Usually gram-positive bacteria –Not a reproductive structure –Survival structure for bad times Inside PM –Form thick walls –Tolerate high heat, dehydration, poisons, radiation –Can survive up to 25 to 40 M years!!!!!!!! –Problem for food industry! Botulism

34. How are spores formed? Sporogenesis –Usually resource scarcity triggers Carbon, nitrogen, etc. –Spore is highly dehydrated Vegetative state Favorable conditions –Germination

35. Prokaryotic domain

36. What are taxonomic groups of bacteria? Gracilicutes –Gram - Firmicutes –Gram + Tenricutes –(no cell cell—e.g. mycoplasmas) Mendosicutes –(Archaebacteria)

37. What’s the difference between a species and a strain? Species: share similar pattern of traits Subspecies/strain/type: same species with differing characteristics Serotypes: unique antibody response in host

38. What about unusual bacteria? Rickettsias –Parasitic, gram negative –Arthropod vector –RMSF –Q Fever

39. Chlamydias –Parasitic –No vector What about unusual bacteria? Photo from: http://www.sexually-transmitted-diseases.info/images/std_chlamydia.jpghttp://www.sexually-transmitted-diseases.info/images/std_chlamydia.jpg

40. What about Mendosicutes? No PPG 70S Extremophiles –Halophiles –Thermophiles –Methanophiles Photo from: http://people.westminstercollege.edu/faculty/tharrison/gslfood/studentpages/pinkwater2.JPGhttp://people.westminstercollege.edu/faculty/tharrison/gslfood/studentpages/pinkwater2.JPG