In an important experiment, a radioactively labeled bacteriophage was allowed to infect bacteria. In a first trial, the phage contained radioactive DNA, and radioactivity was detected inside the bacteria. Next, phage-containing radioactive protein was used, and the radioactivity was not detected inside the bacteria. These experiments led to the conclusion that __________.

• A. bacteriophages can infect bacteria
• B. DNA is made of nucleotides
• C. the genetic material of the phage is protein
• D. genes are on chromosomes
• E. the genetic material of the phage is DNA

Answer: (E)

Verified step by step guidance

1. Understand the experiment setup: A bacteriophage, which is a virus that infects bacteria, was labeled with radioactive markers. In the first trial, the DNA of the phage was labeled, and in the second trial, the protein coat was labeled.
2. Analyze the results of the first trial: When the phage with radioactive DNA infected the bacteria, radioactivity was detected inside the bacteria. This indicates that the DNA entered the bacterial cells.
3. Analyze the results of the second trial: When the phage with radioactive protein was used, no radioactivity was detected inside the bacteria. This suggests that the protein did not enter the bacterial cells.
4. Draw a conclusion from the results: Since only the radioactive DNA was found inside the bacteria, it implies that DNA, not protein, is the material that is transferred into the bacteria during infection.
5. Conclude that the genetic material of the phage is DNA: The experiment demonstrates that DNA is the genetic material responsible for carrying genetic information in the phage, as it is the component that enters the bacteria and not the protein.