Viruses_ Bacteria

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					Viruses& Bacteria
  How do they effect cells?
What are bacteria?
   Single celled LIVING organisms
   Like cells except..
       They don’t have nuclear membranes
   They have distinctive shapes
       Bacilli (rod shaped)
       Spirilla (spiral shaped)
       Cocci (sphere shaped)
Some Beneficial Roles of
   They break down food in our digestive

   They are used in making common products
       Make-up, swiss cheese, yogurt, sour dough
        bread, antibiotics, insulin etc
Some negative roles of
   Bacteria can produce
    TOXINS that affect the
    normal functioning of

   Eg- Anthrax
       Enters the body,
        produces bacterial
        spores, the spores
        produce proteins that
        breakdown the cell walls
        of healthy cells
What are Viruses?
   Viruses are not cells
   They are VERY TINY particles
       Made of a protein coat which
        surrounds its genetic material
       Come in many shapes and sizes
   They are not considered living
       They require a HOST cell to
Virus Reproduction
How can we protect ourselves
from bacteria and viruses?
   Bacteria- we can take ANTIBIOTICS that kill
   Virus- we can get VACCINES before we are
    exposed to the virus
       A vaccine is a weakened or dead form of the virus
        that stimulates the immune system to launch a

1.   Describe one way in which bacteria can
     effect cell functions
2.   Describe how viruses effect cell functions
3.   Outline the events that occur when a virus
     takes over a cell to reproduce