What must a virus do to live?

To live, a virus must do the following:

1. Penetrate a cell. Viruses can only reproduce inside of living cells. They must therefore find a way to penetrate the cell membrane of a suitable host cell.

2. Uncoat. Once inside the cell, the virus must uncoat, or remove its outer protein coat. This reveals the viral genome, which contains the instructions for making new viruses.

3. Replicate. The viral genome is used to make new viral genomes, which are then used to make new viral proteins.

4. Assemble. The new viral proteins are assembled into new viruses.

5. Bud or lyse the cell. The new viruses can either bud from the cell membrane or lyse (burst) the cell, releasing the new viruses into the environment.

Viruses cannot reproduce on their own. They must have a host cell in order to replicate. This is why viruses are considered to be parasites.