Question

Which observation about the phosphorus tracer supported the researchers' conclusion that DNA, and not proteins, transmits genetic information? A. It was in the supernatant only. B. It was in the pellet only. C. It was in both the pellet and the supernatant. D. It was in neither the pellet nor the supernatant.

Answer 1

The radioactive phosphorus tracer was found only in the pellet (option B), indicating that DNA transmits genetic information.

Step-by-step explanation:

The observation that supports the researchers' conclusion that DNA, and not proteins, transmits genetic information is that the radioactive phosphorus tracer was found only in the pellet, which contained the heavier bacterial cells, and not in the supernatant.

This indicates that the genetic material, which carries information to produce more phage particles, is present in the pellet along with the bacterial cells. Since phosphorus is found in DNA but not proteins, the presence of the radioactive phosphorus in the pellet confirms that DNA is indeed the genetic material.

Answer 2

Hershey and Chase demonstrated that genetic material is contained in the DNA molecule. By using bacteriophages they observed that DNA, but not proteins, contains the genetic material. These researchers tagged DNA with radioactive phosphorus and then separated bacteria and protein phages by centrifugation, observing that bacterial pellet was radioactive