What Are The Major Differences Between Bacteria and Viruses?

Illustration from West Valley Internal Medicine

 

The major differences between bacteria and viruses are:

Bacteria can live on their own without a cell, whilst viruses are not considered a living organism since they cannot replicate on their own (although not being a living organism is in dispute by some). Viruses are technically classified as a parasite.

Infections caused by harmful bacteria can almost always be cured with antibiotics (with the exception of most Gram-negative bacteria).

Viruses can lay dormant in the ground until they come into contact with a host. Bacteria can be found everywhere, in soil, plants, animals and humans.

Viruses have no cell structure.

Viruses are 10 to 100 times smaller than bacteria.

Bacteria are intercellular organisms (i.e. they live in-between cells), whereas viruses are intracellular organisms (they infiltrate the host cell and live inside the cell).

Viruses change the host cell’s genetic material from its normal function to producing the virus itself.

Most bacteria are harmless, and there are some useful bacteria but all viruses are harmful.

Bacteria carry all the ‘machinery’ needed for their growth and multiplication. Viruses mainly carry information – for example, DNA or RNA, packaged in a protein and/or membranous coat.  Viruses harness the host cell’s machinery to reproduce.

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