Viruses biology lesson for kids: 1st, 2nd, 3rd, 4th, 5th, 6th and 7th grades biology lesson.
Viruses are some of the simplest organisms in existence. They are very tiny parasites, usually even smaller than bacteria. They aren’t able to do anything on their own, and need host cells in order to reproduce. In some ways, they barely even count as life at all. Influenza and chickenpox are two well-known sicknesses are caused by viruses.
A virus is basically a case of genetic information. Each virus has a protein casing called a capsid, which surrounds its genes. At the core of the capsid, a virus will either have DNA or another kind of genetic molecule called RNA.
Since viruses don’t have the mechanisms to reproduce on their own, they hijack the resources of host cells to do it for them. Their capsids only identify specific kinds of cells, so that they usually only infect specific organisms, or specific cells within an organism.
Once the virus finds its host, it releases its genetic material into the cell. If the virus is an RNA virus, the virus uses its own enzyme to make DNA from the RNA. The virus DNA then enters the DNA of the host cell, which then starts working to make more virus, instead of doing what it is supposed to do to keep itself (and the host, if it is part of a multicellular organism) alive. That is how viruses make you sick.
The infected cell then releases the new viruses into the surrounding environment, so the they spread and infect more cells. It’s also worth mentioning that a virus’s special way of copying itself is not perfect. Small changes are made to their genetic code all the time, meaning that viruses have a high rate of mutation and, therefore, evolution. That makes it hard to treat viral infections, because medicines that work against a virus today might not work against it later on.
Are viruses living things? That’s a hard question to answer. They don’t breathe or grow by themselves the way living things tend to. And they can’t do anything unless they find a host cell to do it for them. Still, they are made up of proteins and genetic material, which is found pretty much only in living things, or things that were living at some point. One thing’s for sure, though: they can reproduce, even though they do it by hijacking other organisms’ resources to do so.
Whether we count them as living or non-living, it is definitely important to know about them so we can protect ourselves against their spread, and find ways to treat them.