Structure Of Prokaryotic Cells And Of Viruses

• List features of prokaryotic/bacterial cells.

  • No nucleus
  • DNA not associated with protein
  • DNA in circular strands called plasmids.
  • No membrane-bound organelles.
  • No chloroplasts
  • 70S ribosomes
  • Cell wall made of murein
  • have outer layer called a capsule.
• Describe the role of the cell wall present in some prokaryotic species.

  Physical barrier that excludes certain substances and protects against mechanical damage and osmotic lysis.
• Describe the role of the flagellum

  Used for movement around the cell
• Define virus.

  Acellular, non-living particles. Smaller than bacteria.
• List features of viruses.

  • Contain nucleic acids (DNA/RNA)
  •  Need to hijack host cell's machinery to reproduce and multiply
  • Enclosed in a protein coat, called a capsid
  • Capsid has attachment proteins which are essential to allow the viruses to identify and attach to a host cell.