Structure of a Virus
A cluster of viral DNA encased in a capsid, a protein coat sometimes encased in a membrane: casings to protect the viral DNA. The virus also has a “body” that includes a neck, collar, sheath, and tail fibers, all made of structure proteins. Here is a diagram of the structure.
Viral method of infection
If the virus has a membrane, the membrane merges with that of the host cell. The cell’s viral DNA then enters the cell and begins taking over the cell’s replication organisms. Most viruses uses the reproduction system of the host cell to replicate its own DNA. The copied viral DNA then exits the cell and moves to infect other host cells. Symptoms come from immune system reactions to this viral takeover. For example, fever as a result of viruses such as the common cold is a precautionary measure to speed up immune reactions and raise the temperature above ideal conditions for virus. Infected cells release cytokines, which are signal enzymes, to attract cells of the immune system such as macrophages to begin to attempt killing off viruses, and to warn surrounding cells of an impending virus to get them to stop replicating. This is how symptoms are felt: excessive mucous, coughing, welts and other marks on this skin (more serious). It is easy for the virus to spread quickly because of its ability to mass produce itself within a cell. They are easier to vaccinate as unless there is any mutation, a vaccine can be developed to give the body immunization to the given virus’ exact DNA/RNA composition. Here is a diagram of the process of viral DNA entering, replicating, and exiting a host cell.
To prevent future infection a vaccine can be given in the form of an injection. The injection is a weakened or dead strand of the virus, but invokes the same immune response. There is not much you can do once you have already been infected by a virus. Antibiotics to not work as they are primarily for bacteria living around and on cells. Viruses are protected because they reside in the nucleus of cells.
DNA (double helix) vs. RNA (single helix, “retroviruses”) viruses
DNA viruses take over the host cell’s replication organelles, and transcribe themselves into RNA. The RNA becomes a means for mass production of new viral DNA. From there, new viruses exit the cell and infect surrounding cells. DNA viruses include Papillomavirus (HPV), Ebola, and the Common Cold. RNA viruses enter the cell and undergo reverse transcription. This means that the converts to DNA using its own enzyme. This enzyme is not particularly accurate and can cause mutation. The virus then spreads itself in the same way as DNA viruses once it has replicated within a host cell. The most notorious retrovirus is HIV.