How does a bacteriophage reproduce?

a bacteriophage is a virus of bacteria.  it produces in the same way as animal viruses (ie it uses the bacterias metabolic machinary and the bacteria sythesises the viral products).

Bacteriophage is a type of virus which acts on bacteria, and as you know, viruses are not living organisms and can't reproduce on their own.
There are two ways a bacteriophage virus can reproduce; it can either undergo the 'lytic cycle' or the 'lysogenic cycle'.

Lytic cycle;
1. The bacteriophage attaches itself to a bacterial 'host cell'.
2. The virus would then inject its DNA into the host cell.
3. The DNA of the virus is now inside the cell, and this starts to replicate and make new viruses within the cell (it's now become a 'little virus making factory' !).
4. The cell becomes more and more filled up with multiplying viruses that it bursts (lysis) and all the viruses are released out.

Lysogenic cycle;
1. The bacteriophage attaches itself to a bacterial host cell.
2. The virus would then inject its DNA into the host cell.
3. The viral DNA then combines with the DNA of the host cell.
4. The bacterial host cell would then reproduce which means that the new cells DNA includes the viral DNA.

Here is a pic of both cycles;
http://img.sparknotes.com/101s/biology/7.1.jpg

Hope that helped!