Bacteria and viruses
Below is a summary that has been brought together in order to show some of the differences between bacteria and viruses.
| Bacteria | Viruses | |
| Brief description | Single-celled, prokaryotic micro-organisms that can survive in animals or the environment | Acellular (has no cell structure) that require a living host to survive |
| Status | Living | Non-living |
| Ribosomes (bind mRNA and tRNA to produce proteins) | Present | Absent |
| Cell wall | Yes – peptidoglycan/ lipopolysaccharide | No – Just a protein coating |
| Structure | DNA and RNA floating freely in cytoplasm. Has cell wall and cell membrane | DNA or RNA enclosed inside a coat of protein |
| Size | Large (1,000nm) | Small (20-400nm) |
| See under light microscope | Yes | No |
| Reproduction | Asexual binary fission | Takes over the host cell causing it to make copies of the viral DNA/RNA |
| Number of cells | One – unicellular | None – not living |
| Free living growth, for example, in the environment | Yes | No |
| Laboratory culture | On agar plates | In cell lines, eggs or tissues. Will not grow on agar plates. |
| Enzymes | Yes | Yes in some |
| Infections | Often localised | Often systemic |
| Treatment of disease | Antibiotics | Antivirals (currently too expensive for animals |
| Vaccines | Yes | Yes |
| Killed by disinfectants | Yes | Yes |
| Benefits | Some bacteria are beneficial, for example, certain bacteria are required in the digestive tract | Viruses are not beneficial although some can be useful in genetic engineering |