Pathogens and Microbiology (Living or Dead? (Living signs (Homeostasis (A…
Pathogens and Microbiology
Living or Dead?
A characteristic of a system that regulates its internal environment and tends to maintain a stable, relatively constant condition of properties.
Whether viruses respond to their environment is one of the trickiest questions to answer. A response to a stimulus is defined by an almost immediate reaction to some change in the environment.
While they don’t change behaviors in response to touch or sound or light the way that humans, bacteria, or sea sponges might, there has not been enough research done to definitively say that viruses do not respond to anything.
One of the basic urges in nature is for a species to pass on its genetic information. Viruses definitely multiply. While our immune system could certainly handle a single virion, it’s the hundreds of thousands of virions created in a short period of time that harm our cells. Viruses must use host cells to create more virions. Since viruses don’t have organelles, nuclei, or even ribosomes, they don’t have the tools they need to copy their genes, much less create whole new virions.
Instead, viruses enter living cells and then hijack the host’s cellular equipment to copy viral genetic information, build new capsids, and assemble everything together. We use the term replicate, instead of reproduce, to indicate viruses need a host cell to multiply.
Living things grow. They use energy and nutrients to become larger in size or more complex. Viruses manipulate host cells into building new viruses which means each virion is created in its fully-formed state, and will neither increase in size nor in complexity throughout its existence. Viruses do not grow.