These are the capsid, the phage genome, and the tail. The tail is used for attachment to the bacterial cell. It has structures that will penetrate the cell membrane and the cell wall, thus allowing the viral genome to be injected into the cell. Although this is the standard appearance of the bacteriophage, there are variations. It can be seen as a side effect of the viral cycle.
Transduction is dependent on the phage's particular developmental cycle.
When generalized transduction occurs, any region of the bacterial DNA can be transferred from on cell to another. Specialized transduction only allows certain bacterial genes close to the insertion site of the phage genome in the bacterial chromosome to be transferred. The two types of transduction occur by different mechanisms. During generalized transduction, bacteriophages accidentally pack bacterial DNA instead of their own. These phages carrying the bacterial DNA are still capable of infecting other cells, but no progeny phages will be produced.