Prokaryotic DNA replication begins at a specific site called the origin of replication. This origin is a specific sequence of nucleotides that is recognized by the proteins involved in initiating replication.

Here's a breakdown:

* Origin of Replication: This is a specific sequence of DNA nucleotides that acts as a starting point for DNA replication.

* Initiation Proteins: Special proteins bind to the origin of replication and initiate the unwinding of the DNA helix.

* Replication Fork: The unwound DNA forms a Y-shaped structure called a replication fork, where DNA synthesis occurs.

So, to answer your question directly, prokaryotic cells copy their DNA replication beginning at the origin of replication.