Viruses vs Bacteria

The differences between bacteria and viruses

Author – Elaine Pendlebury BA BSc  BVetMed DMS MRCVS  Senior Veterinary Surgeon (Science & Welfare) PDSA

• Bacteria (singular is bacterium) are one celled living organisms with complete genetic ‘codes’ made up of DNA and RNA.
• A virus is a section of DNA or RNA enclosed by a protein shell.
• Bacteria are over 100 times larger than viruses, but both can still only be seen by using a microscope.
• Viruses multiply within a living host’s cells but bacteria don’t need this.  They can reproduce on work surfaces, rocks, plastic and other non-living surfaces.  This is one of the main differences between them.
• Bacteria reproduce by splitting its DNA and RNA genetic material into two.  These two new bacteria then are enclosed by the outer protein shell.
• Bacteria can divide and go on to produce millions of bacteria from the one alone.
• Viruses cannot reproduce without a living host.
• They can lie dormant for thousands of years and attack a host when they come into contact with one.
• They enter the host’s body and then clamp onto one of the host’s cells.
• They penetrate the host’s cell and trick the cells to reproduce the virus.
• Viruses are not truly living.  They are essential packs of information (DNA and RNA) that wander around until they meet the living host who produces more virus particles.

Basically, viruses are dead, not alive;  bacteria are alive, not dead