Some of the differences between bacteria and virus are as follows:
| S.N. | Character | Bacteria | Virus |
| 1. | Cell type | Prokaryotic cells | Acellular |
| 2. | Number of cells | Single-celled | No cell |
| 3. | Size | Larger than viruses (0.3-2 μ) | Minute (0.02-0.3 μ) |
| 4. | Microscopy | Visible under Light Microscope. | Visible only under an Electron Microscope. |
| 5. | Shape | Common bacterial cell shapes include cocci (spherical), bacilli (rod-shaped), spiral, and vibrio (comma-shaped). | Viruses typically have spherical (polyhedral), rod-shaped, or helically shaped capsids while some viruses, such as bacteriophages, have complex shapes. |
| 6. | Cellular Machinery | Possesses a cellular machinery | Lack of cellular machinery |
| 7. | Type of organism | Mostly intercellular organisms (i.e. they live in-between cells); some intracellular. | Intracellular organisms (they infiltrate the host cell and live inside the cell). |
| 8. | Structure | Organelles and genetic material within a cell wall | Genetic material within a capsid, some have an envelope membrane. |
| 9. | Cell wall | Cell wall made of peptidoglycan and lipopolysaccharide. | No cell wall. Protein coat presents instead. |
| 10. | Cellular membrane | Cell membranes are present. No sterol except in Mycoplasma cells which have cholesterol. | Some are enveloped but have no membrane function. |
| 11. | Genome | DNA and RNA 1 chromosomeNo histones | DNA or RNA 1 nucleocapsid except in segmented or diploid viruses |
| 12. | Nucleic acid | DNA and RNA float freely in the cytoplasm. | DNA or RNA is enclosed inside a coat of protein. |
| 13. | mRNA | Mono- and poly-cistronic mRNA | Some have poly-cistronic mRNA and post-translational cleavage. |
| 14. | Cell organelles | Presence of non-membrane-bound cell organelles. | Absent. Uses host organelles; obligate intracellular parasites |
| 15. | Ribosomes | 70s ribosomes (30s+50s) | No ribosomes |
| 16. | Living attributes | Living organisms. | Between living and non-living things. |
| 17. | Replication | Binary fission (asexual). DNA replicates cells continuously. | It invades a host cell and takes over the cell causing it to make copies of the viral DNA/RNA. Destroys the host cell releasing new viruses. |
| 18. | The need for host cell | Able to reproduce by itself. | Need a living cell to reproduce |
| 19. | Other forms | In some spore-forming bacteria, sporulating forms can be seen. | Besides viruses, two other acellular forms exist Viroids and Prions. |
| 20. | Cells Infected | Animal, Plant, Fungi | Animal, Plant, Protozoa, Fungi, Bacteria, Archaea |
| 21. | Infection | Localized | Systemic |
| 22. | Induction of Fever | A bacterial illness notoriously causes a fever | A viral infection may or may not cause a fever. |
| 23. | Duration of illness | A bacterial illness commonly will last longer than 10 days. | Most viral illnesses last 2 to 10 days. |
| 24. | Diseases/Infections | Food poisoning, gastritis, and ulcers, meningitis, pneumonia, etc | AIDS, common cold, influenza, chickenpox, etc |
| 25. | Susceptibility to Antibiotics | Most bacteria are susceptible to antibiotics. | The virus does not respond to antibiotics. |
| 26. | Treatment | Antibiotics | Antiviral drugs |
| 27. | Beneficial use | Some bacteria are beneficial (as normal flora, probiotics, fermenters, etc.) | Viruses are not beneficial. However, a particular virus may be able to destroy brain tumors. Viruses can be useful in genetic engineering. |
| 28. | Examples | E. coli, Salmonella spp., Listeria spp., Mycobacteria spp., Staphylococcus spp., Bacillus anthracis, etc. | HIV, Hepatitis A virus, Rhino Virus, Ebola virus, etc. |
