Now, some of the cells will take up that plasmid, but some cells will not take up the plasma. Now, those cells that did take up this plasmid will now have the ability to resist this tetracycline antibiotic because they'll have the gene for it. But those bacterial cells that did not take up this plasma will not have that ability to resist a tetracycline. So if we add the tetracycline antibiotic into that mixture, all the cells that did not successfully uptake this plasmid will essentially die. But the cells that did take up the plasma will live on. And that's exactly how we'll know that all the cells in our solution that remain alive have that plasma that contains that particular gene that we want to replicate.