Structure of prokaryotic cells and of viruses

• Contrast prokaryotic and eukaryotic cells


  - Prokaryotic cells are smaller

  - prokaryotes have no membrane bound organelles

  - prokaryotes have smaller 70S ribosomes

  - prokaryotes have no nucleus - circular -DNA not associated with histones

  - prokaryotic cell wall made of murein instead of cellulose/chitin
• Occasional features of prokaryotes


  - Plasmids - loops of DNA

  capsule - surrounding cell wall - helps agglutination + adds protection

  - flagella for movement
• Features of viruses


  - Non living and acellular

  - contain genetic material, capsid and attachment proteins

  - some (HIV) contain a lipid envelope + enzymes (reverse transcriptase)