WHAT ARE VIRUSES?

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WHAT ARE VIRUSES?

• So small and yet so dangerous

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What is a virus?

• A virus is a small, nonliving particle.
• It consists of a piece of DNA and wears a protein
  coat

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Are viruses living?

• Viruses are not made up of cells
• Do not move, feed, or grow
• Do not use energy
• They can reproduce, but only inside a living cell

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Structure of a virus

• Two parts to a virus
• 1) Head contains DNA and is covered by a protein
  coat called a capsid
• 2) Tail used to anchor virus to a cell

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How are viruses classified?

• Viruses are classified according to the host that
  they invade
• Viruses can infect all living things

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How do viruses reproduce?
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What are some diseases caused by viruses?

• Common cold
• Flu
• Polio
• Rabies
• AIDS
• Smallpox, Chickenpox
• Herpes, hepatitis

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HERE IS A STORY . . .

• A TANK ROLLS UP TO AN AUTOMOBILE FACTORY AND
  BREAKS A HOLE THROUGH THE FACTORY WALL. THE
  TANK CREW ENTERS AND TAKES CONTROL OF THE FACTORY.

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TANK STORY, CONT

• MACHINES ARE RESET, AND MATERIALS ONCE USED TO
  MAKE CARS ARE NOW USED TO BUILD MORE TANKS. Soon
  hundreds of tanks are rumbling through the
  factory. A wall is broken down, and tanks spread
  out into the countryside to attack other
  factories.

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WHAT DOES THE TANK REPRESENT ?

• A VIRUS

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WHAT DOES THE FACTORY REPRESENT?

• A LIVING CELL

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WHAT DOES THE TANK CREW NEED IN ORDER TO BUILD
MORE TANKS?

• THE FACTORY MACHINERY

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HOW IS THIS LIKE A VIRUS AND A CELL?

• VIRUSES CAN ONLY MULTIPLY WHEN IN A LIVING CELL
• A VIRUSS GENETIC MATERIAL TAKES OVER THE CELLS
  FUNCTIONS
• THE CELL PRODUCES THE VIRUSS PROTEINS AND
  GENETIC MATERIAL
• THESE PARTS ARE ASSEMBLED INTO VIRUSES