AP BIOLOGY

Detailed explanation-1: -Hershey and Chase concluded that protein was not genetic material, and that DNA was genetic material. Unlike Avery’s experiments on bacterial transformations, the Hershey-Chase experiments were more widely and immediately accepted among scientists.

Detailed explanation-2: -The protein shell of the virus was tagged with radioactive sulphur, and this ended up in the supernatant. The heavier bacterial cells formed the pellet, so Hershey and Chase knew that DNA was the genetic material of the virus, as the phosphorus was found there.

Detailed explanation-3: -Radioactive elements 32P and 35S were used in Hershey and Chase’s experiments. Phosphorus and sulphur form important constituents of DNA (phosphorus) and certain amino acids (sulphur). Moreover, using the radioactive isotopes of these elements made it easier to trace them during the course of the experiment.

Detailed explanation-4: -Hershey and Chase found that when bacteriophages containing 32P (radioactive), were allowed to infect nonradioactive bacteria, all the infected cells became radioactive and, in fact, much of the radioactivity was passed on to the next generation of bacteriophages.