Definition and Scope of Virology
Virology is the branch of science that deals with the study of viruses and virus-like agents, including their structure, classification, genetics, and interaction with host organisms. As microscopic entities that straddle the line between living and non-living, viruses are unique. They are unable to carry out metabolic processes on their own, and must infect a host cell to replicate. This dependence on living organisms is what makes them distinct from other pathogens, such as bacteria and fungi. Despite their simple structure—typically comprising genetic material (DNA or RNA) encased in a protein coat—viruses have a profound impact on all forms of life, from humans to plants and animals.