A virus is an ultra microscopic, infectious agent that replicates only within the cells of living hosts, mainly bacteria, plants, and animals. Bacteria are one celled organisms that are either spherical, spiral, or rod shaped. They are a part of the Monera kingdom.
Viruses are about 10 to 100 times smaller than bacteria and they must have a living host. Without a living host the virus cannot survive within an organism such as a human or an animal. They literally invade human cells and turn the genetic material from its normal function to producing the virus itself. An example of a virus would be the flu. There is no medicine that can cure a virus; they must simply run their cycle.
Bacteria are single celled organisms that can cause infections in humans. Unlike viruses bacterium can be treated with antibiotics such as Amoxicillin or Penicillin. Some examples of bacterium are bacterial pneumonia or strep throat. These can all be treated with antibiotics. However if you are given antibiotics you must finish all of them or the bacterium will grow back and possibly make you sicker than the first time.
Bacteria are self contained and self reproducing. When the time is right the bacterium will split its DNA and RNA into two. Soon after, separate cell walls will begin to build up around these two bacteria and will continue until there are millions of bacteria formed.
Once a virus has entered the human body it clamps onto a cell and spike chemical coating to penetrate the cell wall. Once it has done that the virus soon replaces the cell's DNA and RNA with its own instructions. Most of the time the instructions are to make as many of that virus as possible. Soon after the cell will outlive its usefulness and explode into individual copies of the virus.
A lot of the times bacteria is harmless, it is used to break down organic matter and destroys harmful parasites. The most common and most harmful bacteria are Streptococcus and E. coli.
A virus on the other hand has no benefit what so ever. Its sole purpose is to create more viruses. Viruses are not considered living creatures because they cannot be killed like bacteria can. The most known virus is HIV/AIDS. Anti-viral medications are one of the biggest experiments now days with the percentage of people with HIV/AIDS on the rise. Scientists are still trying to figure out the structure and genetic programming of viruses. The only way to find a cure for viruses is to learn how to understand them. Unfortunately this could take years before scientists figure it out. On the other hand treating bacteria based diseases can only be of help if we find the most affective antibiotic to use against some pretty nasty bacteria.