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[[Image:Virus.jpg|right|350px|thumb|Microscopic view of a virus.]]

[[Image:Virus.jpg|right|350px|thumb|Microscopic view of a virus.]]

A '''virus''' is a tiny non-[[cell]]ular infectious agent that has two characteristics: It has genetic material (either [[DNA]] or [[RNA]]) inside a protective [[protein]] coat, and it cannot reproduce itself.<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> To reproduce itself, it needs to infect a cell. The genetic material is inserted into the cell, and the reproductive machinery of that cell is then effectively "hijacked": the cell starts to produce components of new virus particles. These components spontaneously self-assemble and the new virus particles can then infect other cells, where the same process happens.

A '''virus''' is a tiny non-[[cell]]ular infectious agent that has two characteristics: It has genetic material (either [[DNA]] or [[RNA]]) inside a protective [[protein]] coat, and it cannot reproduce itself.<ref>Wile, Dr. Jay L. ''Exploring Creation With Biology''. Apologia Educational Ministries, Inc. 1998</ref> To reproduce itself, it needs to infect a cell. The genetic material is inserted into the cell, and the reproductive machinery of that cell is then effectively "hijacked": the cell starts to produce components of new virus particles. These components spontaneously self-assemble and the new virus particles can then infect other cells, where the same process happens.  This infection cycle has two forms.  One a virus will implant its DNA in the host cell's and wait until the cell is under stress and then begin to copy more of itself.  This method allows for the virus gene (called the pro-phage) to continue through multiple generations of cells until the correct replicating time has arrived.  The other method involves a virus directly injecting its genetic material into the cell and immediately forcing it to make viral copies.  After about 200 virues have been produced the cell lyses (explodes) and the copies are now free to infect more cells.

Examples of viruses include the [[influenza]] virus, the common cold, [[smallpox]] and [[polio]].

Examples of viruses include the [[influenza]] virus, the common cold, [[smallpox]] and [[polio]].