Who proved DNA as genetic material -

Options

A. Griffith
B. Bacteria
C. PPLO
D. Hershey and chase

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks who proved that DNA is the genetic material.

2. **Recall Key Experiments**: The key experiment that demonstrated DNA as the genetic material was conducted by Alfred Hershey and Martha Chase in 1952.

3. **Understand the Experiment**: Hershey and Chase used a virus that infects bacteria, known as a bacteriophage. They labeled the DNA and protein components of the bacteriophage with different radioactive isotopes.

4. **Labeling**: They used:
- **32P (Phosphorus)** to label the DNA, since DNA contains phosphorus.
- **35S (Sulfur)** to label the protein, as proteins contain sulfur.

5. **Infection of Bacteria**: The labeled bacteriophages were allowed to infect bacteria. After the infection, they used a blender to separate the viral protein coats from the bacterial cells.

6. **Analysis of Radioactivity**: They then measured the radioactivity in the bacteria. The results showed that only the 32P (DNA) entered the bacterial cells, while the 35S (protein) did not.

7. **Conclusion**: This indicated that it was the DNA, not the protein, that carried the genetic information necessary for producing new viruses. Therefore, they concluded that DNA is the genetic material.

8. **Recognition**: Hershey and Chase's work provided conclusive evidence that DNA is the genetic material, and they were awarded the Nobel Prize for their contributions.

9. **Final Answer**: The correct answer to the question is Alfred Hershey and Martha Chase.

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