Describe how the Hershey-Chase experiment demonstrated that DNA is the genetic material, not protein as previously thought. Explain how they used radioactive isotopes and bacteriophages in their experiment and summarize their conclusions. Distinguish between inducible operons and repressible operons and explain how they work. Describe the three types of prokaryotic genetic recombination (conjugation, transformation, and transduction). Explain how recombination might interfere with the metabolic functions of operons, such as the lac operon or trp operon of E. coli.