Final answer:
The leading idea that proteins carried all the genetic information was known as the tetranucleotide hypothesis. However, in 1952, Martha Chase and Alfred Hershey conducted an experiment that demonstrated the role of DNA as the genetic material.
Step-by-step explanation:
The leading idea that proteins carried all the genetic information was known as the tetranucleotide hypothesis. However, this idea was later disproven. In 1952, Martha Chase and Alfred Hershey conducted an experiment with bacteriophages that conclusively demonstrated that DNA, not proteins, carried the genetic information. This experiment provided confirmatory evidence for the role of DNA as the genetic material.