Viruses – a unique kind of infectious agent

Publisher Summary This chapter discusses the biochemical characteristics of viruses. Viruses can only replicate in living cells. As a consequence, two separate phases can be distinguished in the life-cycle of a virus. Experiments also reveal that viruses occur not only in mammals but also in insects, plants, and prokaryotes. Replication of an animal virus in cells can lead to their destruction. If the replication of a virus in a particular organ is widespread, this may lead to such extensive destruction that symptoms of disease appear. Viruses have been the focus of attention not only because of their importance as disease-causing agents but also because they are interesting subjects for general biological study. Viruses represent the most simplified self-replicating and genetically active elements.