bacteria and archaea

  1. peptidoglycan
    • network of modified sugar polymers ross linked by short polypeptides
    • encloses the entire bacterium and anchors other molecules that extend from its surface

    lacking in archaeal cell walls
  2. gram stain
    used to classify many bacterial species into two groups based on cell wall composition
  3. gram-positive
    bacteria have simpler walls with large amount of peptidoglycan
  4. gram-negative
    less peptidoglycan and structurally more complex with an outer membrane that contains lipopolysaccharides
  5. capsule
    • sticky layer of polysaccharide or protein
    • enables prokaryotes to adhere to their substrate or to other individuals in a colony
  6. fimbriae
    hairlike protein appendages that help prokaryotes stick to their substrate or to one another
  7. nucleoid
    region of cytoplasm that appears lighter than the surrounding cytoplasm
  8. plasmids
    smaller rings of separately replicating DNA
  9. endospores
    • resistant cells produced when essential nutrient is lacking
    • the original cell produces a copy of its chromosome and surrounds it with a tough wall
  10. transformation
    genotype and possibly phenotype of a prokaryotic cell are altered by the uptake of foreign DNA from its surroundings
  11. transduction
    • bacteriophages carry bacterial genes from one host cell to another
    • a type of horizontal gene transfer
  12. conjugation
    genetic material is transferred between two bacterial cells that are temporarily joined
  13. f factor
    • consists of about 25 genes
    • can exist either as aplasmid or as a segment of DNA within a bacterial chromosome
  14. r plasmids
    resistance genes carried by plasmids
  15. photoautotrophs
    photosynthetic organisms that capture light energy and use it to drive the synthesis of organic compounds from COs or other inorganic carbon compounds
  16. chemoautotrophs
    need only as inorganic compound such as CO2 as a carbon source
  17. photoheterotrophs
    harness energy from light but must obtain carbon in organic form
  18. chemoheterotrophs
    must consume organic molecules to obtain both energy and carbon
  19. obligate aerobes
    use O2 for cellular respiration and cannot grow without it
  20. obligate anaerobes
    • are poisoned by O2
    • some live by fermentation
  21. anaerobic respiration
    nitrate ions or sulfate ions accept electrons at the downhill end of electron transport chains
  22. facultative anaerobes
    use O2 if it is present but can also carry out anaerobic environment
  23. nitrogen fixation
    convert atmospheric nitrogen to ammonia
  24. heterocytes
    carry out only nitrogen fixation
  25. biofilms
    surface-coating colonies in which metabolic cooperation between different prokaryotic species occurs
  26. extremophiles
    "lovers" of extreme conditions
  27. extreme halophiles
    live in highly saline environments
  28. extreme thermophiles
    thrive in very hot environments
  29. methanogens
    use CO2 to oxidize H2 releasing methane as a waste product
  30. decomposers
    • breaking down corpses, dead vegetation and waste products
    • unlocking supplies of carbon, nitrogen, and other elemnts
  31. symbiosis
    an ecological relationship in which two species live in close contact with one another
  32. mutualism
    both benefit
  33. commensalism
    one species benefits while the other is not harmed or helped in any significant way
  34. parasitism
    a parasite eats the cells contents, tissues, or body fluids of its host
  35. exotoxins
    proteins secreted by certain bacteria and other organisms
  36. endotoxins
    lipopolysaccharide components of the outer membrane of gram-negative bacteria
Card Set
bacteria and archaea
chapter 27