Patent protection for design patents only lasts for 14 years after the patent is granted, so they offer six years less protection than other patent types. Unlike plant and utility patents, however, no maintenance fee is required to keep a design patent active.
A virus is a small, infectious agent that is made up of a core of genetic material surrounded by a shell of protein. The genetic material (which is responsible for carrying forward hereditary traits from parent cells to offspring) may be either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA).
The structure of a simple virus consists of a protein shell and a viral genome. The size of an ordinary virus usually varies from 10 to 300 nm and it is composed of a viral genome and a capsid. Sometimes there is also an enveloppe. More complex viruses also occur, with two protein shells for example.