A virus is basically a smaller than small sized bit of genetic material, covered in a thin layer of proteins. A virus can do nothing on its own.
Viruses are often confused with bacteria, but bacteria are very different, tells virologist Dr. Schurink. First, bacteria are alive, while viruses are not. A bacterium is a single-celled organism that is self-sustaining. It can even reproduce by splitting itself in two – pretty weird! Bacteria are also extremely important to us. We carry around 1 kilogram of bacteria all over our bodies. Lots of them on our skin, but most of them in our gut. They help out in all manner of small ways, like our digestion and creating vitamins.
Some bacteria can make us sick however. This happens when bacteria end up in places where they shouldn’t be. They can enter your body through a cut in your skin for instance. Or you can ingest them when you eat food that went bad. When you’ve got a bacterial infection, this can be treated with antibiotics. Over time however, bacteria can adapt to antibiotics and become resistant to them. This is bad news, because bacteria can adapt quicker than we can research new antibiotics.