The Differences Between Viruses and Bacteria

Though viruses and bacteria share a number of similar traits, such as being so small that they can only be seen via a microscope, they are both very different organisms. This may come as a surprise to many of you, who may have believed that they were one and the same, so here we are going to look at some of the key differences that separate bacteria and viruses.

Living Conditions

You don’t really think of microorganisms having specific living conditions, but bacteria and viruses, though often occupying the same space, enjoy different living conditions.

Bacteria can and do exists everywhere in the world. This is because they don’t rely on any other organisms to help them live. Viruses, on the other hand, are almost parasitic in nature. Unlike bacteria, they have no cell structure, which means they rely on living creatures to survive.

Living or Non-Living

Though we referred to viruses as organisms at the top of the article, the truth is that many scientists are in disagreement about whether or not they are actually alive. Arguments exist on both sides of the spectrum, though the prevailing one states that the lack of cell structure and the need for a host to survive means that a virus is actually a non-living entity.

By contrast, bacteria are most certainly living things. While they may be organisms that are invisible to the human eye, they are alive and thus are able to act independently.

Effects on Humans

Without exception, a virus is going to have some sort of negative effect on the animal that hosts it. Because of their almost parasitic nature, the human body will fight against the virus, engaging the immune system and increasing cell production to rid the body of the virus, which in turn makes the body ill.

Bacteria are a little more complex, as there are so many different kinds and many already exist in the human body and carry out important functions. On a very simplistic level, you can split bacteria into “good”, “bad”, and “benign”. Some will cause illness, but others will either have no effect on you whatsoever or may even be benefical.


So what about those bacteria that do cause ill effects to humans. Well, by and large, bacteria can be eliminated from the human body with the use of antibiotics, though some have built resistances over the years.

Viruses, on the other hand, are much more complex. Immunization, which is the process of introducing a small amount of the virus to the body so that it creates antibodies which will battle off the full virus later on, can help in some cases. However, at this point in time there are many viruses that are incurable. Examples include HIV and the common cold. In most cases, the symptoms of these viruses are treatable, however, the virus itself doesn’t go away until the end of its lifespan or that of the host.


Another area where bacteria and viruses differ is reproduction. Bacteria are capable of asexual reproduction, which means they don’t even need other bacteria present to create more. Scientists have termed this form of reproduction “Fission” and it essentially involves the single cell of bacteria splitting to create to single-celled bacteria.

Viruses, on the other hand, rely on the cells present in their host’s body to reproduce. In essence, a virus will take over a healthy cell and cause it to make copies of the viruses RNA and DNA. Once the process is completed, the cell is destroyed while releasing more copies of the virus into the host’s system.


Though both microscopic, viruses are actually much smaller than bacteria. In fact, in some cases a single virus may be as much as 100 times smaller than a bacterium. The difference is so vast that viruses are actually considered the simplest form of life known to man.


As mentioned previously, many bacteria are actually beneficial to people. Your stomach, for example, contains millions of bacteria that help in the digestion and processing of food.

In all cases, viruses have negative effects on the body. However, recent research has indicated that some viruses may be used in destroying brain tumours, though much more research needs to be completed to see if such a method is viable. Genetic engineers also uses viruses in their research, meaning they can indirectly lead to breakthroughs.

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