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Unformatted text preview: Intro Bio I (BIO 311C), Fall 2009, Dr. Bushart Homework #8 1. How does the Hershey-Chase experiment illustrate that DNA is the transformative agent? Be specific in regards to conclusions and hypotheses. In a first experiment, they labeled the DNA of phages with radioactive Phosphorus-32 (the element phosphorus is present in DNA but not present in any of the 20 amino acids from which proteins are made). They allowed the phages to infect E. coli, then removed the protein shells from the infected cells with a blender and separated the cells and viral coats by using a centrifuge. They found that the radioactive tracer was visible only in the pellet of bacterial cells and not in the supernatant containing the protein shells. In a second experiment, they labeled the phages with radioactive Sulfur-35 (Sulfur is present in the amino acids cysteine and methionine, but not in DNA). After separation, the radioactive tracer then was found in the protein shells, but not in the infected bacteria, supporting the hypothesis that the DNA)....
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This note was uploaded on 11/16/2009 for the course BIO 50465 taught by Professor Wandelt during the Spring '09 term at University of Texas.
- Spring '09