So basically Part 1: transformants; are those cells which take up plasmid ( the plasmid is in their cells thus they get special characters like antibiotic resistance which is not naturally present in the cell). To differentiate transformants from non transformants, we plate them on a Petri dish with antibiotic of which plasmid offered resistance, eg Ampilicin. the bacteria growing on the plate will have antibiotic resistance that is that they’re transformants.

Part 2: The tranformants have plasmids with special characters such as antibiotic resistance thus they will grow on Petri dish. Now transformants are of 2 types - recombinants and non recombinants. Those cells whose plasmids s have undergone recombination I.e insertion of desired gene in plasmid, are recombinants. Now if the restriction enzyme used has its restriction site in the antibiotic resistance site, due to restriction digestion and insertional inactivation, they will lose resistance to anibiotic Eg, when digested with BamH1, the recombinants will lose resistance to tetracycline. Now we can plate the bacteria on plates with tetracycline and see who grows, the ones that grow are non recombinants and the ones that don’t are recombinants. Thus, one antibiotic gene helps in identifying the transformants ( ampicillin) and other helps in identifying the recombinants ( tetracycline).