Difference Between Virus And Bacteria

What is Bacteria?


Bacteria are the oldest, structurally simplest, and the most abundant forms of life on earth. They are also the only organisms with the prokaryotic cellular organization. Represented in the oldest rocks from which fossils have been obtained, 3.5 to 3.8 billion years old, bacteria were abundant for over 2 billion years before eukaryotes appeared in the world.

They are the most abundant living organisms. Bacteria lack the high degree of internal compartmentalization characteristic of eukaryotes.

Many serious human diseases are caused by bacteria, some of them responsible for millions of deaths each year.

Importance of Bacteria. Bacteria have had a profound impact on the world’s ecology, and play a major role in modern medicine and agriculture.

What is a Virus?


A virus is a tiny intracellular which contains either DNA or RNA genome and sometimes with some associated enzymes. This is then surrounded by a protein coat (capsid) which is then (often) surrounded by a membrane (mostly protein & carbohydrates). This membrane may be made up part of the membrane of infected cells.

                                 Differences between Virus and Bacteria

Characteristics Bacteria




Cell Wall Lipopolysaccharide or Peptidoglycan Protein coat present instead. No cell wall.


Number of cells Unicellular No cells
Ribosomes Present Absent
Non-Living/Living Living organisms Between living and non-living things.
Infection Localized Systemic
RNA and DNA RNA and DNA floating freely in the cytoplasm. RNA and DNA enclosed inside a coat of protein.
Reproduction Fission- a form of asexual reproduction Invades a host cell and takes over the cell causing it to make copies of the viral DNA/RNA.
Reproduce Able to reproduce by itself Need a living cell to reproduce
Treatment Antibiotics Virus does not respond to antibiotics.
Diseases/Infections Gastritis, Food poisoning, ulcers, meningitis, and pneumonia etc. AIDS, common cold, influenza, chickenpox, etc.
Examples Staphylococcus aureus, Vibrio cholerae, etc. HIV, Hepatitis A virus, Rhino Virus, etc.

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Practise This Question

In non-primate mammals like cow, sheep, rat, dog etc.,cyclical changes occurring during their reproductive phase is called