Hershey and Chase are best known for their experiments conducted in the 1950s that helped confirm that DNA, not protein, is the genetic material in organisms. They used the T2 bacteriophage, a virus that infects bacteria, for their experiments.
Key Discoveries:
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DNA as the Transforming Factor: In their classic experiments, Hershey and Chase used radioactive isotopes to label the DNA and proteins of the T2 phage. They found that when the virus infects the bacteria, only the DNA (and not the protein) enters the bacterial cells. This provided strong evidence that DNA carries the genetic information necessary for viral replication.
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Base Pairing in DNA: In the context of DNA structure, the bases that pair together are adenine (A) with thymine (T), and cytosine (C) with guanine (G). This complementary base pairing is essential for DNA replication and the transmission of genetic information.
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Shape of DNA: While Hershey and Chase did not specifically discover the double helix structure of DNA (which was elucidated by James Watson and Francis Crick), their work set the stage for understanding DNA's role in heredity and molecular biology.
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Bacteria and Bacteriophages: Hershey and Chase's experiments demonstrated that bacteria and bacteriophages do have DNA; in fact, the experiments illustrated how DNA acts as the genetic material in these organisms. The confusion in your question may stem from the fact that bacteria do not have a nucleus like eukaryotic cells but do possess circular DNA (plasmids) and a single chromosome.
Overall, Hershey and Chase's work was crucial in establishing DNA as the molecule responsible for heredity in living organisms.
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