micro week 3 chptr 4

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  1. How are Prokaryotes Different from Eukaryotes?
    • The way their DNA is packaged
    • –No nucleus
    • –Not wrapped around histones
    • The makeup of their cell wall
    • –Bacteria- peptidoglycan
    • -Archae- tough and made of other chemicals, distinct to them
    • Their internal structures
    • –No complex, membrane-bound organelles
  2. Prokaryotic Form and Function
    What are the external parts of a prokaryote?
    • Appendages- Flagella, Pili, Fimbriae
    • Glycocalyx - capsule, slime layer
  3. what are the cell envelope parts of a prokaryote?
    • cell wall
    • cell membrane
  4. what are the parts of the internal prokaryote (6)?
    • cytoplasm
    • ribosomes 
    • inclusions
    • nucleoid/chromosome
    • actin cytoskeleton
    • endospore
  5. Structures Common to all Bacterial Cells
    • •Cell membrane
    • •Cytoplasm
    • •Ribosomes
    • •One (or a few) chromosomes
    • Structures found in most bacterial cells:
    • •Cell wall
    • •Surface coating or glycocalyx
  6. Structures found in some bacterial cells
    • •Flagella
    • •Pili
    • •Fimbriae
    • •Capsules
    • •Slime layers
    • •Inclusions
    • •Actin cytoskeleton
    • •Endospores
  7. External structures of prokeyotes 
    appendages are:
    are appendages present on all species?
    can provide what?
    which can be used for attachment and mating?
    • cell extentions
    • no but are common
    • motility (flagella and axial filiments)
    • pili and fimbriae
  8. what are the 3 parts of prokaryote flagella?
    • filament 
    • hook
    • basal body
  9. describe polar arrangment of flagella?
    flagella attached at one or both ends of the cell 
  10. flagella
    monotrichous - 
    single flagellum
  11. flagella
    lophotrichous - 
    small bunches or tufts of flagella emerging from the same site
  12. flagella
    peritrichous - 
    dispersed randomly over the structure of the cell
  13. flagella 
    amphitrichous - 
    a single flagellum at either end of the cell
  14. Flagellar Function
    taxis - 
    move toward or away from stimuli
  15. axial filaments are also known as?
    periplasmic flagella or endoflagella
  16. where is axial filaments enclosed?
    in the space between the cell wall and the cell membrane 
  17. rotation of the axial filiments cause what?
    cell to move
  18. describe the physical characteristics of Pili?
    Elongate, rigid tubular structures, hollow
  19. what are Pili made of?
    protien pilin
  20. where are pili found?
    gram negative bacteria
  21. what are pili used in?
    conjugation - a process to transfer DNA from one cell to another
  22. fimbriae allow bacteria to do what? why is this important?
    • stick to surfaces and each other
    • important for reproduction
  23. glycocalyx consist of what?
    polysaccharides and protiens
  24. glycocalyx protect the cell from what?
  25. how do glycocalyx differ from bacteria 
    • thickness
    • orginazation
    • chemicle composition
  26. glycocalyx are formed by?
    many pathogenic bacteria- protect the bacteria from phagocytes
  27. glycocalyx are important in formation of what?
  28. majority of bacteria have cell envelope where does it lie?
    outside cytoplasm
  29. the cell membrane is composed of?
    2-3 basic layers
  30. what are the 2-3 basic layers of the cell envelope?
    • cell wall
    • cell membrane
    • in some bacteria, the outer membrane
  31. how many layers does gram positive bacteria have? what about gram negative?
    • gram pos - 2 layers
    • gram neg - 3 layers
  32. what are gram positive bacteria consist of? what about gram negative?
    • gram pos - cell wall and cytoplasmic membrane
    • gram neg - outer membrane, cell wall, and cytoplasmic membrane
  33. what does the structure of the cell wall help to determine?
    the shape of a bacterium
  34. cell walls of bacterium are strong and rigid because the contain what?
  35. the structure of the cell wall prevents what?
    osmotic lysis
  36. cell walls are targeted by what?
    many antibiotics they have little protection from lysis
  37. Gram-positive cell wall characteristics:
    • A thick (20 to 80 nm), homogeneous sheath of peptidoglycan
    • Contains tightly bound acidic polysaccharides
  38. characteristics of Gram-Negative Cell Wall
    • Single, thin (1 to 3 nm) sheet of peptidoglycan
    • Periplasmic space surrounds the peptidoglycan
  39. Some bacteria aren’t characterized as either gram-positive or gram-negative
    Some don’t have a cell wall at all. what is an example?
    Archae- unusual and chemically distinct cell walls
  40. gram negative outer membrane are similar to the cell membrane exept for containing what to things?
    specialized polysaccharides and proteins
  41. what does the uppermost layer of gram-negative bacteria contain?
  42. innermost layer- 
    phospholipid layer anchored by lipoproteins to the peptidoglycan layer below
  43. the 
Card Set
micro week 3 chptr 4
micro week 3 chptr 4
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