Bacteria and Viruses — Definition

Definition

Bacteria are cellular microorganisms with a prokaryotic organisation, while viruses are acellular infectious entities that depend on host cells for replication. Bacteria have cellular machinery and diverse metabolic roles; some cause disease, while many participate in ecological processes or useful associations.

Viruses contain genetic material within a protein coat and sometimes an envelope, but they do not reproduce independently through cellular division. The distinction explains why antibiotics used against bacterial targets do not treat a viral infection itself.

It also prevents the mistaken inference that the human patient, rather than a microorganism, becomes antibiotic-resistant.