Types of Viruses
One example of this structure is the adenovirus. It uses its pentons or the extended arm like protein, to bind to the receptors on the cell membrane. Once attached, as it gets pulled in, it breaks through the membrane and releases the viral DNA
An example of a spherical virus, would be the flu. It would bind to the cell membrane of a cell, then enter the cell releasing RNA to replicate protein for more viruses
Tobacco mosaic virus is helical structured virus. Once it enters a plant, the virus breaks up into many TMV RNA and infect more cells.
Complex viruses are like Bacteriophage. They land on the surface of cells and inject the viral genome into the cell.