Micro Fact: Bacteria vs. Virus

Posted by Tami Port Jul 1, 2008

New Resource for Quick Micro Answers

Most people looking for information on the internet want to be able to quickly reach straightforward explanations that specifically address their question. This Microbiology blog will be frequently updated with answers to common cell and microbiology questions.

What Is the Difference Between Bacteria and Viruses?

Bacteria

Bacteria are single-celled living prokaryotic organisms. Prokaryotes are evolutionarily ancient, simple cells. But simple and primitive certainly doesn’t mean unsuccessful. These microbes are found nearly everywhere. Some bacteria live independently, others exist in symbiotic relationships that can be beneficial to humans (such as the normal flora that exists in our GI tract and helps us digest food and produce vitamins). Other types of bacteria are pathogens which cause illness (such as Staphylococcus aureus, MRSA is a particularly virulent strain of this species).

Viruses

These infectious agents are not alive and all are parasites. Viruses are not considered a life form because they are not made of cells; they do not grow; they cannot reproduce on their own; and they don’t transform energy (metabolize nutrients).

Viruses must infect a living cell in order to make more viruses. A viral particle is composed of at least genetic material (DNA or RNA) and a protective protein coat called a capsid. There are no viruses that are directly beneficial to us, although we have found ways to use viruses to our benefit, such as viral cancer therapy.

See Suite101 Microbiology topic or SPO's Virtual Microbiology Classroom for more information on microbes and infectious disease.