AP BIO Chapter 27

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AP BIO Chapter 27
2013-05-03 13:26:33
AP BIO Chapter 27

AP BIO Chapter 27
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  1. peptidoglycan-
    in most bacterial cell walls which is a polymer composed of modified sugars cross-linked by short polypeptides.
  2. Gram stain-
    allows scientist to classify many bacterial species into two groups based on differences in cell wall composition
  3. Gram-positive-
    bacteria have simpler walls with a relatively large amount of peptidoglycan
  4. Gram-negative-
    bacteria have less peptidoglycan and are structurally more complex, with an outer membrane that contains lipopolysaccharides
  5. capsule-
    the cell wall of many prokaryotes is surrounded by a sticky layer of polysaccharide or protein. it is the layer is dense and well defined or a slime layer it it is less well organized.
  6. fimbriae
    hairlike appendages that some prokaryotes stick to their substrates or to one another
  7. pili
    appendages that pull two cells together prior to DNA transfer from one cell to the other.
  8. taxis-
    a directed movement toward or away from a stimulus and about half of all prokaryotes are capable of.
  9. nucleoid
    a region of cytoplasm that appears lighter than the surrounding cytoplasm that appears lighter than the surrounding cytoplasm in electron micrographs
  10. plasmids-
    in addition to its single chromosome, a typical prokaryotic cell may also have much smaller rings of independently replicating DNA molecules
  11. transformation
    the genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings.
  12. transduction
    phages carry prokaryotic genes from one host cell to another.
  13. conjugation
    DNA is transferred between two prokaryotic cells (usually of the same species) that are temporarily joined.
  14. F factor
    the ability to form pili and donate DNA during conjugation results from the presence of a particular piece of DNA. The F factor can exist either as a plasmid or as a segment of DNA within the bacterial the bacterial chromosome.
  15. F plasmid-
    The F factor in its plasmid form. Cells containing the F plasmid function as DNA donors during conjugation.
  16. Obligate aerobes-
    must use oxygen for cellular respiration and cannot grow without it
  17. Obligate anaerobes-
    are poisoned by oxygen
  18. anaerobic respiration-
    used to extract chemical energy in which substances other than oxygen such as nitrate ions or sulfate ions accept electrons at the downhill end of electron transport chains
  19. Facultative anaerobes-
    use oxygen if it is present but can also carry out fermentation or anaerobic respiration in an anaerobic environment
  20. nitrogen fixation-
    some cyanobacteria and some methanogens (a group of archaea) convert atmospheric nitrone to ammonia
  21. heterocysts-
    carry out only nitrogen fixation.
  22. biofilms-
    metabolic cooperation between different prokaryotic species often occurs in surface-coating colonies
  23. extreme thermophiles-
    thrive in very hot environment
  24. methanogens
    archaea that release methane as a byproduct of their unique ways of obtaining energy
  25. page 568
  26. decomposers-
    breaking down dead organisms as well as waste products and thereby unlocking supplies of carbon, nitrogen, and other elements
  27. symbiosis-
    an ecological relationship in which two species live in close contact with each other
  28. mutualism
    an ecological interaction between two species in which both benefit example is in many cases in which a prokaryote and its host participate
  29. Exotoxins-
    are proteins secreted by certain bacteria and other organisms. the bacterium does not have to be present.
  30. Endotoxins-
    are lipopolysaccharide (carbohydrates bonded to lipids) components of the outer membrane of gram-negative bacteria.
  31. bioremediation-
    the use of organisms to remove pollutants from soil
  32. mixotrophs-
    type of protist that combine photosynthesis and heterotrophic nutrition
  33. endosymbiosis-
    the process in which certain unicellular organisms engulf other cells