Micro Test 1

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  1. Compare prokaryotes to Eukaryotes.
    Eukaryotes are larger, have a nucleus and membrane-bound organelles. Prokaryotes are more chemically complex, have no cytoskeleton or cytoplasm and have smaller ribosomes. Prokaryotes have a single circular DNA lacking histones, eukaryotes have multiple linear chromosomes with histones. Eukaryotes divide by mitosis, prokaryotes by binary fission and eukaryotes sexually reproduce by meiosis.
  2. Which groups of organisms are prokaryotes?
    Bacteria of all kinds
  3. Which groups of organisms are eukaryotes?
    Protozoans, algae, fungi, plants and animals
  4. How to bacteria reproduce?
    By binary fission which is a method of asexual reproduction in which an organism splits into two.
  5. What are some ways to tell single celled organisms apart?
  6. What are the three main bacterial shapes?
    Coccus, Bacillus and Spiral
  7. What are the different arrangements for the bacterial shape coccus (round)?
    Single, Diplococci (two), streptococci (chain), tetrad (four), sarcinae (cube), staphylococci (bunch)
  8. What are the different arrangments for the bacterial shape bacillus (pill shape)?
    Single, Diplobacilli (two), streptobacilli (chain), coccobacillus (squished, almost round)
  9. What are the different arrangments for the bacterial shape spiral?
    Vibrio (hotdog), spirillium (slight spriral), spirochete (corkscrew)
  10. What is monomorphic?
    Bacteria maintains a single shape
  11. What is polymorphic?
    Bacteria which can take on many shapes depending on their environment
  12. What is pleomorphic?
    Bacteria whose genes allow them to take many shapes
  13. What is a glycocalyx?
    A sticky, gelatinous coating consisting of polysaccharides and/or polypeptides which surrounds the cell wall.
  14. What is a dense glycocalyx called?
    A capsule
  15. What is a loose glycocalyx called?
    A slime layer
  16. What is a monotrichous flagella arrangement?
    A single flagella
  17. What is an amphitrichous flagella arrangement?
    Flagella at each end
  18. What is a lophotrichous flagella arrangment?
    Two or more flagella at one end
  19. What is a peritrichous flagella arrangement?
    Flagella all over
  20. Describe the three parts of a flagella.
    Filament: long outer region made of flagellin protein. Hook: thicker base made of slightly different protein. Basal Body: portion anchoring into cell wall and plasma membrane
  21. How does a flagella work?
    They move by rotation of the basal body either clockwise or counter clockwise moving the cell along by "runs" and "tumbles" allowing motion in any direction.
  22. What are axial filaments?
    Bundles of fibers just beneath the outer sheath which are anchored at both ends of the bacteria. Their rotation propels spirochetes in a spiral motion.
  23. What are fimbrae?
    Thin, straight "hairs" found in many G- bacteria. Used to colonize mucus membranes and other surfaces.
  24. What are pili?
    Longer than fimbrae and are usually found in ones or twos on the sides of bacteria. Used to join bacteria in conjucation for DNA transfer.
  25. What is taxis?
    Movement of the cell towards or away from a stimulus
  26. What is chemotaxis?
    Movement in response to chemicals
  27. What is phototaxis?
    Movement in response to light
  28. What is photophobic?
    Repelled by light
  29. What is hydrophilic?
    Repelled by water
  30. What is a cell wall good for?
    Gives bacteria their shape, protects against changes in water pressure and concentration.
  31. What is peptidoglycan?
    Composes bacterias cell walls. Made of protein and sugar
  32. Where is peptidoglycan found in a G- cell, a G+ cell?
    G- Cell: inbetween phospholipid bylayer. G+ Cell: On the outside layer.
  33. What is LPS?
    Lipopolysaccharides, found in the outer membranes of G- cells.
  34. Why do G+ and G- cells stain differently in a gram stain?
    Because G+ cells have peptidoglycan on the outside which stains purple, G- cells have PG on the inside and don't stain.
  35. What is the mechanism of action of penicillin?
    Bacteria constantly remodel their peptidoglycan cell walls. Bacteria that attempt to divide in the presence of penicillin fail to do so, and instead end up shedding their cell walls.
  36. Why doesn't penicillin harm animal cells?
    Penicillin kills bacteria by interfering with the ability to synthesize cell wall. Since human cells do not have cell walls it does not kill them.
  37. What is a plasma membrane made of?
    A phospholipid bylayer containing channel proteins
  38. Why are cell membranes described as selectively permeable?
    Because only some molecules can get through such as H2O, O2 and CO2. Others have to pass through channel proteins
  39. What is a chromatophore?
    Infoldings of the plasma membrane that extend into the cytoplasm where pigments and enzymes involved in photosynthesis are found.
  40. What type of membrane and solute concentrations must exist for osmosis to occur?
    • 1.A partially pemeable membrane.
    • 2.A difference in water potential on opposite sides of the membrane. Moves from high concentration to low concentration.
  41. What is the difference between a plasmid and a nucleoid?
    a plasmid is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA. The nucleoid is a region within the cell that contains the genetic material
  42. What is an inclusion?
    Reserve deposits found in both procaryotes and eucaryotes. Types: metachromatic granules, polysaccharide granules, lipid, sulfur, carboxysomes and gas vacuoles.
  43. What is an endospore?
    small, thick-walled time capsules that allow bacteria to survive for long periods of time in a dormant state until external conditions improve
  44. What is sporulation?
    The formation of an endospore. It begins when a key nutrient is low or absent. A newly replicated bacterial chromosome & some cytoplasm are isolated by an ingrowth in the plasma membrane.
Card Set:
Micro Test 1
2013-03-07 00:06:33
Prokaryotic Cells

Micro Ch 4 - Prokaryotic Cells
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