Viruses

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Viruses

• LN 13

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What is a Virus?

• Viruses are a lot smaller than bacteria or animal
  cells.
• Unlike cells that are living, viruses are
  nonliving.
• They are unable to grow and reproduce on their
  own and therefore must infect cells to do so.

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Viral Structure

• Unlike cells, viruses are NONLIVING.
• Viruses are simple
• DNA or RNA
• Instructions to build more viruses
• Protein
• Protects the instructions
• The only way a virus can reproduce is to infect a
  cell

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Virus Reproduction

• Viruses attach to a specific type of cell and
  injects its nucleic acid into the cell.
• Once inside the viral nucleic acid takes over the
  cell.
• The cell begins to produce viral nucleic acid and
  proteins.
• New viruses are made and the released.
• The host cell dies.

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Viruses and Cells

• Without cells viruses could not reproduce.
• Viruses can infect both prokaryotic and
  eukaryotic cells.
• Viruses are specialized they have one type of
  cell they infect.

Eukaryotic Cell
Prokaryotic Cell
Multi and Single celled Have Organelles
Single Celled (Bacteria) Do Not have Organelles
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Modes of Infection

• Virus may live outside of the host, until ready
  to infect.
• Route of infection for cold virus
• Nose
• Eyes
• Mouth
• Nasopharynx
• Once inside the body, virus will target and
  infect a cell.

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How to prevent spread

• Wash your hands
• Viruses can be on
• Phones
• Money
• Door handles
• Anything we touch
• Dont share drinks or food.
• Sneeze into your sleeve or tissue
• Throw away used tissues

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Summary

1. What is a virus?
2. What must a virus do in order to reproduce?
3. What are virus made of?
4. Describe the steps for virus replication (2 or
   more sentences.
5. How are viruses and cells different?
6. What are the modes of infection?
7. How can you prevent the spread of viruses?