30 Difference Between Bacteria and Virus (With Table)

When I started teaching microbiology at the University of Mississippi ten years ago, I realized that many students found it hard to distinguish some microscopic organisms.

We did research as a department and came up with teaching techniques that made the work of learners look easier. I came up with a list of differences between various microscopic organisms.

So, what is the main difference between bacteria and viruses? The former are living things that can reproduce independently whereas the latter are non-living things that rely on the host cell for replication.

Understanding the difference between bacteria and viruses is crucial in the preparation of a microbiology exam. Continue reading this article for further explanation and differences.

Difference Between Bacteria and Virus

Comparison Table (Bacteria vs Virus)

Basic Terms Bacteria Viruses
SizeLarger (1000 nm)Smaller (20-400 nm)
Cell TypeProkaryotic cellsAcellular
Number of CellSingle-cellNo cell
MicroscopyVisible under light microscopeVisible under an electron microscope
ShapeCocci have a spherical shape

Bacilli have rod-shape

Spiral and vibrio have comma shape

Have spherical shapes, rod-shaped, helical shapes.

Some viruses like bacteriophages have complex shapes

Cellular MachineryPresentAbsent
Type of organismIntercellular organism and some are intracellular organismsStrictly intracellular organism
StructureOrganelles and genetic materials are enveloped by the cell wall.Genetic materials are enclosed in the capsid. Other have a cell membrane.
Cell wallPresentAbsent
Cell membranePresent in some bacteriaAbsent
GenomeDNA and RNA

1 chromosome

No histones


1 nucleocapsid except in segmented or diploid viruses

Nucleic acidFloating freely in the cytoplasmEnclosed inside a protein coat
mRNAMono- and poly-cistronic mRNASome have poly-cistronic mRNA and post-translational cleavage.
Cell organellesPresent. But are non-membrane bound.Absent
Ribosomes70s ribosomes (30s+50s)Absent
Living attributesLiving organismBoth living and non-living organism
ReplicationBinary fission or asexual reproduction.Invade the host cell for replication.
ReproductionAble to reproduced independentlyDepend on living cell for reproduction
Other formsSpore forming bacteriaViroids and Prions
Cell infectedAnimal, Plant, FungiAnimal, Plant, Protozoa, Fungi, Bacteria, Archaea
Induction of feverBacterial disease causes feverMay or may not cause fever
Illness durationCan last more than 10 daysCan last between two to ten days.
DiseasesFood poisoning, gastritis, and ulcers, meningitis, pneumonia.AIDS, common cold, influenza, chickenpox
Susceptibility to AntibioticsProne to antibioticsDo not respond to antibiotics
TreatmentAntibioticsAntiviral drugs
SignificanceFlora, prebiotics, and fermenters are usefulIdeal in genetic engineering.
MetabolismWithin the cellViruses do not metabolize
IncubationWithin 1 to 2 weeksWithin few days to two weeks
ExamplesE. coli, Salmonella spp., Listeria spp., Mycobacteria spp., Staphylococcus spp., Bacillus anthracis, etc.HIV, Hepatitis A virus, Rhino Virus, Ebola virus, etc.

What Are Bacteria?

Bacteria are prokaryotes found in the ecosystem. These unicellular organisms can grow in harsh conditions such as hot springs.

Bacteria are classified according to morphological structures. Cocci have a spherical shape, bacilli have rod-shaped, vibrio has comma shape and spirilla has a spiral shape.

Bacteria are surrounded by cell membranes. The cell membrane encloses the cytoplasm that contains nutrients, DNA, proteins, and other essential components.

Bacteria contain non-membrane-bound organelles. Proteins are transported by the cytoskeleton and have circular chromosomes in the nucleoid.

Bacteria are either heterotrophs or autotrophs. The carbon source is the carbon dioxide in autotrophs and organic compounds in heterotrophs.

What Is Virus?

Viruses are non-living things. The genetic material is representing as either DNA or RNA enclosed by the protein core. These viruses infect the life of animals, plants, bacteria, and archaea.

Virion is a complex virus with genetic material covered by capsid. The capsid is a protective protein coat encoded by the viral genome.

Examples of viruses’ groups are dsDNA viruses, ssDNA viruses, dsRNA viruses, dsRNA viruses, (+) ss RNA viruses, (-) ss RNA viruses, ssRNA-RT viruses, and dsDNA-Rt viruses.

The main orders of viruses include Caudovirales, Herpesvirales, Ligamenvirales, Mononegavirales, Nidovirales, Picornavirales, and Tymovirales.

Main Differences between Bacteria and Virus

  1. Bacteria reproduce independently whereas viruses need host cells for reproduction.
  2. Bacteria are living things whereas viruses are non-living things.
  3. Bacteria are larger while viruses are smaller
  4. Bacteria contain cell walls whereas viruses lack a cell walls.
  5. Bacteria have circular chromosomes whereas viruses have DNA or RNA strand.
  6. Bacteria have ribosomes while viruses lack ribosomes.
  7. Bacteria experience metabolism within the cell whereas viruses do not experience metabolisms.
  8. Bacteria are cellular machinery while viruses are non-cellular machinery
  9. Bacteria are either beneficial or harmful while viruses are harmful to life.
  10. Bacteria cause localized infection whereas viruses cause systemic infection

Similarities between Bacteria and Virus

  1. Both cause infection
  2. Both have a harmful effect
  3. Both can be prevented

In Conclusion

The main difference between bacteria and viruses is that the former is larger and can reproduce independently while the latter is smaller and depend on the host cell for reproduction.

Both bacterial and viral infections can be prevented. Bacteria can be prevented by the use of antibiotics and viruses through vaccination.

More Sources and References


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