Eubacteria(True Bacteria)

Eubac­te­ria (“True Bac­te­ria”)

• Char­ac­ter­is­tics:
  • Rigid cell wall
  • Fla­gel­lum (if motile)
• Cyanobac­te­ria (Blue-Green Algae):
  • Con­tain chloro­phyll a (sim­i­lar to plants)
  • Pho­to­syn­thet­ic autotrophs
  • Forms: Uni­cel­lu­lar, colo­nial, fil­a­men­tous
  • Habi­tats: Fresh­wa­ter, marine, ter­res­tri­al
  • Often form blooms in pol­lut­ed water
  • Some fix nitro­gen in spe­cial­ized cells called het­e­ro­cysts (e.g., Nos­toc, Anabae­na)
• Chemosyn­thet­ic Autotrophs:
  • Oxi­dize inor­gan­ic sub­stances (nitrates, nitrites, ammo­nia) for ener­gy (ATP pro­duc­tion)
  • Impor­tant in nutri­ent recy­cling (nitro­gen, phos­pho­rus, iron, sul­fur)
• Het­erotroph­ic Bac­te­ria:
  • Most abun­dant type of bac­te­ria
  • Roles:
    • Decom­posers
    • Food pro­duc­tion (e.g., curd from milk)
    • Antibi­ot­ic pro­duc­tion
    • Nitro­gen fix­a­tion in legume roots
  • Pathogens: Cause dis­eases in humans, crops, ani­mals (e.g., cholera, typhoid, tetanus, cit­rus canker)
• Repro­duc­tion:
  • Fis­sion: Pri­ma­ry mode of repro­duc­tion
  • Spore for­ma­tion: Under unfa­vor­able con­di­tions
  • Prim­i­tive form of sex­u­al repro­duc­tion: DNA trans­fer between bac­te­ria
• Mycoplas­ma:
  • Lack a cell wall
  • Small­est liv­ing cells known
  • Can sur­vive with­out oxy­gen
  • Many are path­o­gen­ic to ani­mals and plants