Not truly alive, viruses and are entities that take control of a cell and use it to produce more of themselves. They aren’t considered alive because they cannot reproduce themselves, relying on an infected cell to do that for them. They also are not the same thing as bacteria. Bacteria are alive. Viruses happen to be complicated, having multiple classes each with its own unique attributes.
Viruses reproduce by injecting the host cell with their DNA and other genetic material. The cell now creates the proteins required for the assembling of the virus. Having all the proteins in the cell, the virus self-assembles itself, breaking out of the cell and going on to infect more cells. The body must learn how to combat the slyness of the virus. When a virus is fought off and defeated, the body forms white blood cells that are trained to hunt down the certain virus it was created to kill.
Another contagion to the cell that isn’t alive is the prion. This type of enemy agent is known to be the cause of Mad Cow Disease and the human counterpart and others. It works by misfolding proteins, which in turn misfold other proteins, systematically creating long chains of misfolded proteins. Their is no cure found yet for treating prion-caused diseases.
Yet another type of virus is the retrovirus. It is a class six virus whose function reverses the pattern normal to viruses by using its RNA to form DNA inside the cell. Usually, a virus will inject the cell with its RNA, and the cell will produce more RNA. In the case of the retrovirus, the new viral DNA is integrated into the cell’s genome, eventually making more of the DNA virus.
As the above paragraphs state, viruses are not alive but replicate themselves through host cells. They infect the cell, altering the normal function to reproduce more virus.