Which molecule did Hershey and Chase conclude is the genetic material?

• A. Protein
• B. DNA
• C. RNA
• D. Lipids

Answer: (B)

What this question tests is which molecule truly carries genetic information. In the Hershey-Chase experiment, scientists used bacteriophages and labeled the DNA with radioactive phosphorus while labeling the protein coats with radioactive sulfur. After the viruses infected bacteria, they separated the viral coats from the cells. The radioactivity found inside the bacterial cells came from the DNA label, not the protein label, meaning the DNA entered the cells and directed the creation of new viruses. This shows that DNA stores and transfers genetic information in this system, not the protein coat. The other options don’t fit because the experiment demonstrates the protein remains outside the cell while DNA goes inside to guide replication; lipids aren’t involved in storing genetic instructions.