Two Life Cycles of a Virus

                                                       Lytic versus lysogenic life cycles:

In the lytic stage, many viral particles are made and copies are sent back into the environment.

A virus is found in this phase when conditions are favorable, i.e. when bacteria is "growing like crazy"

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     The virus attaches to bacteria (host)
                       


     The virus inserts its DNA into the bacteria



     The virus takes over the cell's machinery

 

     The virus reproduces itself and self-assembles. 
                    The host cell is destroyed

 

In the lysogenic phase there is no pathology.  
Under certain conditions the lysogenic lifestyle can switch to a lytic lifestyle.

A virus is found at this stage under harsh conditions.

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The virus is a prophage at this stage.


 

     The virus binds to bacteria (host)


     The virus inserts its DNA into the bacteria


    
     The viral DNA gets incorporated into the cell's chromosome

 


     Viral DNA is replicated
     along with chromosomal material

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