Griffith performed an experiment to prove the chemical nature of genetic material. In Griffith's experiment .

Options

A. the protein coat from pathogenic cell was able to transform non - pathogenic cells.
B. heat killed pathogenic cells caused pneumonia.
C. some substance from pathogenic cells was transferred to non - pathogenic cells and causes transformation.
D. the polysaccharide coat of bacteria caused Pheumonia.

Answer

To solve the question regarding Griffith's experiment and its conclusions about the chemical nature of genetic material, we can break down the information step by step.

### Step-by-Step Solution:

1. **Understanding Griffith's Experiment**: In 1928, Frederick Griffith conducted experiments using two strains of the bacterium *Streptococcus pneumoniae*: the S strain (smooth, virulent) and the R strain (rough, non-virulent).

2. **Initial Observations**:
- When mice were injected with the S strain, they developed pneumonia and died.
- When injected with the R strain, the mice remained healthy.

3. **Heat-Killing the S Strain**:
- Griffith then heat-killed the S strain (rendering it non-virulent) and injected it into mice. The mice survived, indicating that the heat-killed S strain did not cause disease.

4. **Combining R Strain with Heat-Killed S Strain**:
- In a crucial experiment, Griffith mixed the heat-killed S strain with live R strain and injected this mixture into mice. Surprisingly, the mice died.

5. **Conclusion of the Experiment**:
- Upon examining the dead mice, Griffith found live S strain bacteria. This indicated that some "transforming principle" from the heat-killed S strain had transformed the R strain into the virulent S strain.

6. **Identifying the Transforming Principle**:
- The experiment suggested that the genetic material responsible for this transformation was likely DNA, although Griffith himself did not identify it as such.

7. **Evaluating the Options**:
- **Option A**: "The protein coat from pathogenic cell was able to transform non-pathogenic cells." - This is incorrect; the transformation was not due to the protein coat.
- **Option B**: "Heat-killed pathogenic cells caused pneumonia." - This is incorrect; heat-killed cells did not cause pneumonia.
- **Option C**: "Some substance from pathogenic cell was transformed to non-pathogenic cell and caused transformation." - This is correct; this describes the essence of Griffith's findings.
- **Option D**: "The polysaccharide coat of bacteria caused pneumonia." - This is incorrect; the polysaccharide coat protects the bacteria but does not directly cause pneumonia.

8. **Final Answer**: The correct option is **C**: "Some substance from pathogenic cell was transformed to non-pathogenic cell and caused transformation."