How do viruses differ from other microorganisms such as bacteria?

Viruses differ from bacteria because they are not true living organisms outside a host. Bacteria are complete living cells that can grow, metabolize, and reproduce on their own, while viruses can only reproduce inside a living cell.

Viruses are acellular, made up only of genetic material (DNA or RNA) enclosed in a protein coat. They lack cytoplasm, ribosomes, or a cell wall. Bacteria, on the other hand, are unicellular prokaryotes with a simple cell structure, including a cell wall, cytoplasm, and ribosomes.

In terms of size, bacteria are much larger (0.5–5 micrometers) and visible under a light microscope, whereas viruses are smaller (20–300 nanometers) and can only be seen with an electron microscope.

Reproduction is another key difference. Bacteria multiply by binary fission independently, while viruses require a host cell to replicate by hijacking the host’s genetic machinery.

Diseases caused by bacteria include tuberculosis, typhoid, and cholera. Viral diseases include influenza, polio, measles, HIV/AIDS, and COVID-19.