Cells

• Cytokinesis

  Cytoplasm divides.
• Viruses

  Acellular, non-living particles. They are 20-300nm. Contain nucleic acids (DNA or RNA). Replicate inside host cells. Nucleic acid incloses in the capsid. Some contain a lipid envelope as well.
• Non specific defence mechanisms

  • Physical barrier (skin)
  • Phagocytosis
• Specific defence mechanisms

  • Cell mediated response (T lymphocytes)
  • Humoral response (B lymphocytes)