CH. 4

• cell structure(A)

  no spiral or mycelial shapes, unique features like RNA gene structure and methanogensis; have features in common with eukarya (gene encoding) and bacteria (genes for metabolism)
• cell envelope (A)

  s layer may be only layer outside the plasma membrane; some lack cell walls, generally no capsules or slime layers
• cell membranes (A)

  composed of unique lipids with isoprene units and ether linkages rather than ester; some are monolayer and ignicoccus is the only with outer membrane
• cell walls (A)

  lack peptidoglycan and most common wall is the S layer; may have a protein sheath or pseudomurein; no translocation
• ribosomes (A)


  have additional 5.8s subunit of RNA; proteins are more similar to eukarya than bacteria
• nucleoids (A)

  usually not membrane bound, 1 chromosome (evidence of polyploidy though), and proteins to aid in folding
• pili (A)


  not well understood, have a lumen like bacteria flagella and may be involved in adhesion
• cannulae

  tubelike structure on thermophilic Pyrodictium; unknown function, production in daughter cells?
• hami


  grappling hook-like structure, adhesion?
• flagella (A)

  thinner, not hollow, and growth occurs at base rather than at end; made of more than one type of protein