What is a common characteristic of viruses?

A common characteristic of viruses is that they take over the functions of the host cell. Viruses are unique in that they cannot replicate on their own; they require a host cell to reproduce. Once a virus infects a host, it injects its genetic material into the cell, hijacking the cell's machinery to produce more viral particles. This dependence on a host cell for reproduction and function is a defining feature of viruses, distinguishing them from living organisms, which can carry out metabolic processes independently.

Understanding this characteristic is essential when studying virology and the impact of viruses on living organisms, as it highlights how viruses can manipulate biological processes within their hosts, leading to disease and other significant effects on health and ecology.