Viruses

• What are viruses?

  Microscopic particles which replicate inside the cells of living organisms. Viruses are acellular - not made up of cells and not living.
• What are the 7 life processes?

  Movement

  Respiration

  Sensitivity

  Growth

  Reproduction

  Excretion

  Nutrition
• Label the structures of a virus particle:

  .

  A) Viral envelope

  B) Enzymes

  C) Glycoprotein

  D) Genetic material

  E) Capsid

  
• What are the functions of the structures found in a virus particle?

  • Genetic material = instructions for making new copies of virus
  • Capsid = contains and protects genetic material
  • Viral envelope = Outer layer made from fatty lipid molecules taken from cells in the host
  • Glycoproteins = help virus to recognise and bind to cells in host organism
  • Enzymes = in some viruses, to convert RNA into DNA
• What are bacteriophages?

  Viruses that use bacteria as a host. Look like the cookie robots from the minions movie.

  
• What are the steps of viral replication?

  • Virus attaches to a cell
  • Penetrates cell membrane and injects its DNA or RNA into cell
  • Viral nucleic acid replicates using host cellular machinery
  • New viral particles are released from host cell - cell may be destroyed in the process