You probably already know that viruses are responsible for causing a number of diseases, from AIDS to the flu. But did you ever wonder how a virus works? Viruses are basically infectious particles that take over the operation of a cell for the sole purpose of manufacturing new viruses. How exactly does a virus do this? In many ways it works in the same manner as a computer virus does – it has to first gain access and then convince the machinery within the device, in this case a cell, to make multiple new copies of the virus. There are many different types of viruses, but they do share some similar characteristics. First of all, viruses are usually specific in the types of cells that they infect. The specificity of the virus is dependent upon the types of receptors that are found on the surface of the target cell. Every cell in your body has a pattern of protein receptors on its surface. The virus uses these proteins to target specific cells for infection. In this example, the genetic material of the virus infecting the cell is DNA. However, unlike the complex DNA found in the nucleus of a cell, the DNA of a virus is relatively simple, and just contains the information needed to manufacture new virus parts. Once inside the cell, the instructions in the DNA are transcribed to RNA. The protein-building machinery of the host cell then translates these instructions into the components of a new virus. These parts are then assembled into new viruses within the host cell. These parts are then assembled into new viruses within the host cell. When ready, they emerge from the host cell, often killing it in the process. As they emerge, some viruses retain parts of the host cell membrane, forming an envelope around the virus. This envelope gives some protection to the virus from the immune system of the host organism. Each new virus is now capable of infecting another host cell and repeating the process of virus replication. By understanding how the life cycle of a virus works, scientists have been able to develop antiviral drugs that target specific points in the virus life cycle and thus prevent the virus from replicating.