A 2.2 CELL STRUCTURE - Prokaryotic Cell Structure

• what 2 domains can prokaryotes be classified into

  Eubacteria and Archaea (bacteria and archaebacteria)
• What is Eubacteria?

  "true bacteria"; all of the organisms traditionally known as bacteria
• What is archea?

  typically found in extreme environments such as high temperatures and salt concentrations and include methanogens (exist in anaerobic conditions)
• what is the general size of prokaryotic cell

  0.1 - 5.0 um (very small)
• Do prokaryotic cells have a nucleus?

  No nucleus
• overall structure of a prokaryotic cell

  not divided into compartments and lack membrane-bound organelles (except ribosomes)
• what are the structures most common to prokaryotes?

  ribosomes, DNA in loop, cytoplasm, plasma membrane, cell wall
• ribosomes in prokaryotes

  70S (structurally smaller) and is responsible for the binding and reading of mRNA during translation to produce proteins
• DNA in prokaryotes

  naked, single circular DNA molecule located in the nucleoid and plasmids
• what are plasmids


  small loops of DNA that are separate from the main circular DNA molecule and contain genes that can be passed between prokaryotes
• cytoplasm in prokaryotic cells

  site of cellular reactions, where ribosomes are found and has the major component of cytosol
• what is cytosol

  water-based solution that contains ions, small molecules and macromolecules
• what is the cell membrane of a prokaryote composed of

  lipid bilayer which has the function of controlling which substances enter and leave the cell
• how is membrane different in archaea

  have a monolayer instead of a bilayer
• what are prokaryotic cell walls made of

  murein/peptidoglycan (glycoprotein)
• function of a cell wall

  acts as protection, maintains the shape of the cell and prevents the cell from bursting
• additional structures in prokaryotes

  plasmids, capsules, flagellum, pili
• capsule


  A sticky layer that surrounds the cell walls of some bacteria, protecting the cell surface and sometimes helping to glue the cell to surfaces.
• flagellum


  long, tail-like structures that rotate, enabling the prokaryote to move
• Pili


  shorter and thinner structures than flagella
• when did prokaryotes originate

  first organism to evolve on earth and still have the simplest structure
• Where are prokaryotes found?

  everywhere