The experiment which proved conclusively that during infection only DNA of the bacteriophage enters the host cell and the protein coat stays behind was conducted by

Options

A. F. Griffith
B. Aery, macleod and Mc carty
C. Sutton and Boveri
D. Hershey and Chase

Answer

To answer the question regarding the experiment that proved that during infection only the DNA of the bacteriophage enters the host cell while the protein coat remains outside, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Experiment**: The experiment in question is commonly referred to as the "blender experiment." This experiment was pivotal in demonstrating the role of DNA in heredity.

**Hint**: Think about the terminology used in molecular biology experiments that involve mixing or blending components.

2. **Recognize the Scientists Involved**: The experiment was conducted by two scientists, Alfred Hershey and Martha Chase. They are well-known for their work in molecular genetics.

**Hint**: Remember that the names of scientists often appear in pairs for significant experiments in biology.

3. **Understand the Methodology**: In their experiment, Hershey and Chase used bacteriophages (viruses that infect bacteria) to determine whether DNA or protein was the genetic material. They labeled the DNA with radioactive phosphorus and the protein coat with radioactive sulfur.

**Hint**: Consider how labeling different components can help trace their path during an experiment.

4. **Analyze the Results**: After allowing the bacteriophages to infect bacteria, they used a blender to separate the viral protein coats from the bacterial cells. They found that only the radioactive DNA entered the bacterial cells, while the protein coats remained outside.

**Hint**: Think about how separation techniques can reveal which components are involved in a process.

5. **Conclude the Findings**: The results of the Hershey-Chase experiment conclusively demonstrated that DNA is the genetic material responsible for heredity, as only the DNA entered the host cells during infection.

**Hint**: Reflect on how conclusions are drawn from experimental data in scientific research.

### Final Answer:
The experiment that proved conclusively that during infection only DNA of the bacteriophage enters the host cell and the protein coat stays behind was conducted by **Alfred Hershey and Martha Chase**.