Life Cycle of a Virus

• What's a parasite 


  Something that lives + feeds of a host
• What are the 4 types of pathogens

  • Bacteria = reproduce rapidly + release toxins
  • Viruses = replicate by getting inside cells + making the cells make copies of them
  • Fungi = reproduce by producing spores
  • Protists = type of parasite + can't live or multiply outside of host
• What are viruses 


  • Not cells
  • Have a protein coat around a strand of genetic material
  • Infect shot cells to reproduce
  • Specific types of viruses only infect specific cells
• What are the 2 pathways of a virus

  • Lytic pathway
  • But some can also enter the lysogenic pathway
• Describe the lytic pathway

  • Virus attaches itself to a specific host
  • Injects it's genetic material into cell
  • Uses cell's proteins + enzymes to replicate it's genetic material + produce components of new viruses
  • Components assemble
  • Host cell splits open (undergoes lysis) + releases new viruses -> infects more cells
• Describe the lytic pathway again

  • Virus attaches itself to a specific host
  • Injects it's genetic material into cell
  • Uses cell's proteins + enzymes to replicate it's genetic material + produce components of new viruses
  • Components assemble
  • Host cell splits open (undergoes lysis) + releases new viruses -> infects more cells
• Describe the lysogenic pathway

  • Virus attaches itself to specific host cell + injects genetic material
  • Injected genetic material incorporated into genome of host cell
  • Virus's genetic material get replicated along with host's DNA every time it divides
  • Virus now dormant
  • New viruses made
  • Eventually a trigger like presence of chemical -> virus genetic material leaves genome
  • Enters lytic pathway
• Describe lysogenic pathway again

  • Virus attaches itself to specific host cell + injects genetic material
  • Injected genetic material incorporated into genome of host cell
  • Virus's genetic material get replicated along with host's DNA every time it divides
  • Virus now dormant
  • New viruses made
  • Eventually a trigger like presence of chemical -> virus genetic material leaves genome
  • Enters lytic pathway