Basic purpose of this lecture is to present on Virus Structure and Method of Invasion. Here briefly present on Viral Structure: they are not a cell; surrounded by protective protein coat; Genetic material carries information for multiplication and Hijacks biochemical machinery of host cell to carry these processes out. Virus can lie dormant for many years until it comes into contact with a suitable host cell and binds with molecules on surface of host cell. Finally focus on alteration of cell instruction.