Discovery of DNA's structure and function Original Scenario-Based Practice

Questions

1. 1.

   During an immersive historical simulation of Cold Spring Harbor in 1952, an archivist tests an unknown bacteriophage sample to recreate the landmark discovery of the hereditary molecule. One culture of bacteriophages is tagged with radioactive phosphorus-32 while an identical culture is labeled with radioactive sulfur-35. After allowing each culture to infect Escherichia coli host cells, the archivist agitates the samples in a mechanical blender and centrifuges the mixtures to separate cell bodies from extracellular fluid. Which observation from this simulation confirms the historical role of DNA as the genetic material?

   • A) Sulfur-35 accumulated inside the bacterial pellet, showing that protein capsids entered the host interior to govern offspring production.
   • B) Both phosphorus-32 and sulfur-35 remained suspended in the supernatant, revealing that genetic transfer occurs strictly across external cell membranes.
   • C) Phosphorus-32 was concentrated inside the bacterial pellet while sulfur-35 remained in the supernatant, demonstrating that viral DNA enters the host cell.
   • D) Phosphorus-32 remained exclusively in the supernatant alongside empty viral coats, establishing that nucleic acids act merely as external structural supports.

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