The virus itself is nothing more than a membrane—a sort of envelope—that contains the genome, the genes that define what the virus is. It is usually spherical (it can take other shapes), about 1/10,000 of a millimeter in diameter, and it looks something like a dandelion with a forest of two different-shaped protuberances—one roughly like a spike, the other roughly like a tree—jutting out from its surface. These protuberances provide the virus with its actual mechanism of attack.
