What are viruses?

Viruses are a kind of germ. Germs are small organisms that can live in people, plants, and animals. Sometimes they can make us sick and some germs are good. There are germs that live in our intestines that we can not live without. They make a type of chemical that we need. We give them food and a place to live.

There are three other types of germs besides viruses: bacteria, fungi, and protozoa.

Viruses are very tiny organisms. Some people used to say that they were not living because they can not breathe, move, or grow on their own. Viruses have to be inside a plant or animal cell to reproduce. The person, plant, or animal that a virus lives in is called its host. Inside a host cell, the virus uses the host’s ribosomes to make many copies of its own genes.

One virus particle is not called a cell. It is called a virion. A virion has a protein shell shaped sort of like a dreidel without a handle or sometimes like a spiral tube. The shell acts like a spaceship, protecting the virus genes as they travel between cells. The virus genes inside a host cell make the proteins to build more virus shells called capsids.

The virus genes are packaged inside the capsid and then break out to infect more host cells.



In people, viruses cause many illnesses. They cause chickenpox, measles, the flu, and the common cold.

Right now I am the host to a virus that causes the common cold.