Microbiology Chapter 4.txt

  1. Cell Shapes
    • Bacillus
    • Coccus
    • Spirals
  2. Bacillus
    • Rod shaped
    • Single or strepto only, no chains
  3. Coccus
    • Sphere
    • Cocci
    • Single, occasional pairs, tetrad (group of four), cluster and chain
  4. Spirals
    • Vibrios
    • Spirilla
    • Spirochetes
    • Never in clusters or chains
  5. Vibrios
  6. Spirilla
    Rigid cell wall, flagella on each end for movement
  7. Spirochetes
    • Flexible cell wall
    • Moves like a snake
    • Syphilis
  8. Outside Cell Structures
    • Flagella
    • Pili
    • Glycocalyx - Slime Layer and Capsule - protects, hides things that antibodies can be made against.
    • Cell wall
  9. Capsule
    • Protects, hides things that antibodies can be made against.
    • Makes it too big to be engulfed by phagocytes
  10. Cell Wall
    • Strength and shape
    • N acetyl glucosamine
    • N acetyl muramic Acid
    • Teiocholic acid
  11. Pili
    • Pili are protein fibers extending from the surface of many prokaryotes
    • Attach cells to surfaces
    • Form biofilms and microcolonies
    • Some bacterial species have conjugation pili, used to transfer genetic material between cells, like plasmid, pieces of DNA that have antibiotic resistance
  12. Flagella
    • Location & number determined by genetics
    • Prokaryotic flagella are long appendages extending from the cell surface
    • Flagella can be used for cell motility
    • Prokaryotic flagella contain a helical filament, a hook, and a basal body
    • Bacteria exhibit chemotaxis, moving up the concentration gradient of a chemical attractant
    • Some prokaryotes move without flagella by gliding across a solid surface
    • Spirochetes contain endoflagella, which move the cell through torsion exerted on the cell by endoflagellar rotation
  13. Chemotaxis
    Cells will move towards nutrients (move up the concentration gradient)
  14. Monotrichaete
    single flagella
  15. Amphitrichaete
    Flagella on both ends
  16. Lophotrichaete
    Flagella on one end
  17. Peritrichaete
    Flagella all over
  18. Glycocalyx
    • Not all bacteria have this candy coating
    • Polysaccharide composition (complex carbs with some minor small proteins)
    • When it's thick it's considered a slime layer or capsule
    • Can help with attachment
    • Mostly for protection
  19. Cell Envelope
    • Capsule
    • Cell wall
    • Cell membrane
    • Cell wall
    • Keeps the cell from bursting
    • A tough and protective external shell
    • The cell wall protects the cell from injury, and to maintain cell shape and water balance
  20. Gram+ cell wall
    • 3 proteins, Nag, Nam & teichoic acid
    • Nag and Nam are tied like ropes and the teichoic acid binds them together
    • A thick peptidoglycan cell wall containing teichoic acid
  21. Gram- cell wall
    • Only 1 layer of Nag & Nam between the outer membrane and cell membrane
    • Thinner than G+
    • Has an outer membrane
    • Without teichoic acid, it doesn't hold the crystal purple stain
    • A two-dimensional peptidoglycan layer and no teichoic acid
  22. Penicillin
    Prevents the making or repair of the peptidoglygan layer so it's more effective against G+
  23. Gram negative outer membrane
    • Separated from the cell membrane by the periplasmic space
    • Contains proteins called porins that selectively allow small molecules into the periplasmic space
  24. Cell membrane
    • Made of triglycerides - 3 fatty acids and 1 glycerol
    • Permeability barrier
    • The cell membrane is a fluid layer of phospholipid and protein (the fluid mosaic model)
    • The phospholipid molecules are arranged in a bilayer
    • Antimicrobial substances may disrupt or dissolve the bilayer
  25. Cell membrane proteins perform or aid in many functions, such as
    • Cell wall synthesis
    • Energy metabolism
    • DNA replication
    • Sensation of stimuli
    • Molecule transport
  26. Phospholipid bilayer
    • Hydrophobic fatty acid chains in the phospholipids form a permeability barrier
    • 2 layers facing each other
    • ooooooooo o = a glycerol
    • |||||||||||||||||||||| = 2 fatty acids and a phosphate for each glycerol
    • ooooooooo o = a glycerol
  27. Porins
    Proteins that form pores in the outer membrane that selectively allow small molecules into the periplasmic space
  28. Inside Cell Structures
    • Cytoplasm
    • Ribosomes
    • Chromosome
    • Metachromatic granules
    • Magnetosome
    • Plasmids
    • The nucleoid region
    • A central subcompartment in the cytoplasm where DNA aggregates
  29. Prokaryotic Chromosome
    • The chromosome is usually a closed loop of DNA and protein
    • Only 1
    • Circular
  30. Plasmids
    • Smaller pieces of DNA
    • Non-essential info
    • Small, circular
    • Exchanged through the sex pilus
    • Each plasmid is a closed loop, containing 5-10 genes
    • Can be used as vectors in genetic engineering
    • R plasmids carry genes for resistance to antibiotics
  31. Metachromatic granules
    • Dark staining
    • Blobs of phosphate
    • Found in diptheriae
  32. Genome
    The complete set of genes is called the genome
  33. Haploid
    Most cells have only one copy of each gene (are haploid), so cannot undergo mitosis like eukaryotes
  34. Ribosomes
    There are hundreds of thousands of ribosomes, used for protein synthesis
  35. Inclusion bodies
    Inclusion bodies store nutrients or building blocks for cellular structures
  36. Lysozyme
    • Destroys peptidoglycan layer of cells
    • It's more effective in killing G+ because G+ has lots of PG
  37. Gas vesicles
    Some aquatic bacteria use gas vesicles to float on the water�s surface
  38. Magnetosomes
    Magnetosomes contain crystals of magnetite or greigite, allowing cells to respond to magnetic fields
  39. Mycoplasmas
    • Phylogenetically related to G+
    • No cell wall
    • Believed that they once had a cell wall but lost it because of their parasitic relationship with their host.
  40. Compare Gram Positive and Gram Negative Cell Walls
    • Peptidoglycan Both
    • Teichoic acids G+
    • Outer Membrane G-
    • Lipopolysaccharids (LPS) G-
    • Porin proteins G-
    • Periplasm G-
  41. Fluid mosaic model
    The mosaic of phospholipids and proteins are not cemented into place but rather they can move laterally in the membrane
  42. Cytoskeleton
    • Thought it didn't exist until recently
    • Proteins homologous to those in eukaryotic cytoskeletons are present
  43. Prokaryotes contain a homolog of eukaryotic tubulin.
    It forms filaments similar to those found in microtubules. It regulates cell division. Localizes around the neck of the dividing cell where it recruits other proteins needed for the deposition of a new cell wall between the dividing cells.
  44. Proteins homologous to eukaryotic actin
    Can help determine cell shape
  45. Crescentin
    A homolog to eukaryotic intermediate filaments, also assists in cell shape
  46. Homolog
    • An entity with similar attributes due to shared ancestry
    • How many phyla are in the domain Bacteria?
    • The majority of the 18 phyla of Bacteria play a positive role in nature
  47. Proteobacteria
    Contain the largest and most diverse group of species, including E. coli and many human pathogens
  48. Firmucutes
    Consist of many gram-positive species, such as Bacillus, Clostridium, Staphylococcus, and Streptococcus
  49. Actinobacteria
    Include Streptomyces, the genus that produces the antibiotic streptomycin
  50. Cyanobacteria
    Carry out photosynthesis using chlorophyll, responsible for the appearance of oxygen in Earth�s early atmosphere
  51. Chlamydiae
    Are extremely small, mostly pathogenic bacteria
  52. Archea
    • Contain many extremophiles
    • methanogens (live in anoxic environments)
    • extreme halophiles (salt-lovers)
    • thermoacidophiles (grow at high temperatures with low pH)
  53. Crenarchaeota
    Tend to grow in hot, acidic environments such as hot springs and volcanic vents
  54. The Archaeal Cell Wall
    • Provides Mechanical Strength
    • No archaea have peptidoglycan in the cell wall, but some have pseudopeptidoglycan
    • Others have polysaccharides, proteins, or both
  55. The S-layer is the most common archaeal cell wall, consisting of protein or glycoprotein in a crystal lattice
  56. The Archaeal Cell Membrane Differs from Bacterial and Eukaryal Membranes
    • Hydrophobic lipid tails are attached to glycerol differently in archaea
    • Fatty acids are usually absent
    • Adjacent lipid tails are bound together forming a lipid monolayer, instead of a bilayer
  57. Transport of molecules
    Can be passive (facilitated diffusion) or active (active transport)
  58. Facilitated diffusion
    Passive transport of molecules
Card Set
Microbiology Chapter 4.txt
Microbiology Four