D. both sulfur and phosphorous isotopes
The experiment involved inserting both a phosphorous isotope (^32P) into the bacteriophages' DNA and a sulfur isotope (^35S) into a protein in the bacteriophages' capsids. Therefore, both sulfur and phosphorous isotopes would appear in the new bacteriophages produced after infection.
In 1952, Alfred Hershey and Martha Chase conducted an experiment about bacteriophage reproduction. They inserted a phosphorous isotope (^32P) into the bacteriophages' DNA, and a sulfur isotope (^35S) into a protein in the bacteriophages' capsids. Hershey and Chase then infected bacteria with the bacteriophages. After infection, they put the bacteria in a blender to separate the cells from the extracellular matter. They measured the percentage of isotopes that remained in the extracellular matter.
Use the passage to answer the question.
The scientists also examined the new bacteriophages produced after infection. Based on the graph, which isotope(s), if any, appeared in these new bacteriophages?
A. no isotopes
B. sulfur isotopes
C. phosphorous isotopes
D. both sulfur and phosphorous isotopes
1 answer
1 answer