In addition to the extracts and the plasmid DNA, are there any additional materials you should add ...

You will probably add exogenous nucleoside triphosphates to serve as the building blocks needed to make new strands of DNA. Although these monomers will be present in the extracts, they will be present at lower concentrations than are normally found inside the cell. They may also be subject to hydrolysis, and the nucleoside diphosphates that are the products of this hydrolysis are not usable substrates for DNA replication. For both of these reasons, it is important to add excess nucleotides to the reaction mixture for efficient DNA replication to occur.

Makes more sense now, ty