ABSTRACT
The proteins of viruses have structural, enzymatic, or regulatory properties. The function of the virion or virus particle is to initiate an infection and promote the replication of more virions by exploiting the environment and enzymes of the host cell. Viruses have no intrinsic means to generate energy so they must rely totally on the metabolic machinery of host cells to synthesize new viral components. Viruses produce a wide range of disorders ranging from acute inflammatory disorders to chronic degenerative disorders. Some viruses like the respiratory syncytial viruses may cause cell membranes to fuse when viral envelope proteins are inserted at the plasma membrane of the host cell. Viruses have no innate ability to generate energy, so they must rely totally on the metabolic machinery of host cells. Particular problems are created by persistent viral infections which may cause tissue injury by promoting inflammatory processes in infected tissues.
