Animation - Entry of Virus into Host Cell

How are viruses able to enter cells?

In order for a virus to infect a cell, it must bring its DNA or RNA into contact with the host cell. Therefore, infection requires that the virus get through the cellular membrane. Some viruses remain outside the cell. They attach to the membrane at specific receptor sites. Once attached the virus injects its DNA or RNA into the cell. Enveloped viruses are enclosed in a membrane similar to that of the host cell. The virus and the envelope fuse and the virus enters the cell through endocytosis. In the first example only the genetic material enters the cell. In the second case the entire virus with the exception of the envelope enters the cell.

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