Transcript:

Virus Edge of LifeWhat is a virus? This week we're running a series of programs on viruses as relevant as when they were first broadcast in 2016. I'm Jim Metzner and this is the Pulse of the Planet.McDonald: Viruses are considered to be on the edge of life. They're not living organisms, but they require to enter our cells to replicate. Sarah McDonald is an assistant professor at the Virginia-Maryland College of Veterinary Medicine and the Virginia Tech Carilion Research Institute. McDonald: Viruses are capsules with either DNA or RNA stuffed inside of them. They are essentially inert when they are in the environment, but when they get inside of our cells, they multiply and replicate themselves hundreds of thousands of times over. That's how virus disease is caused. It's caused by the virus replicating within our cells.So what is a virus? If it's not a living entity, what is it? It's thought to be non-living because it can't replicate by itself. It has no capacity to store or produce energy. So it requires a living entity or a living organism, for it to propagate. The elements that comprise a virus are also within cells. So, the question is, which came first? Did the cell with all its molecules come first, and then the virus somehow hijacked some of these molecules from a cell and created this brand new entity that then came back and became a parasite to our cell, and hijacked our cell. Or was it the reverse? Whereby, a virus, maybe was the donor of some of these very simple molecules that the cell then utilized for its own propagation and biology.And the answer is?McDonald: Oh, nobody knows that answer ! (laughs)We'll hear more on viruses in future programs. I'm Jim Metzner and this is the Pulse of the Planet.