What is the inference extracted from Griffith's transformation experiments?

Options

A. Replication of DNA is semi-conservative in nature.
B. DNA is the genetic material
C. There is some genetic material, which is responsible for transformation.
D. Bacteria lacks genetic material.

Answer

**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). The S-strain has a polysaccharide coat that protects it from the host's immune system, making it virulent, while the R-strain lacks this coat and is non-virulent.

2. **Conducting the Experiment**:
- Griffith injected mice with the S-strain, and the mice died, confirming that the S-strain is virulent.
- He then injected mice with the R-strain, and the mice survived, confirming that the R-strain is non-virulent.
- Next, he injected mice with heat-killed S-strain bacteria, and the mice also survived, indicating that heat-killing the bacteria rendered them non-virulent.

3. **Key Experiment**: The crucial part of Griffith's experiment involved injecting mice with a mixture of heat-killed S-strain and live R-strain. The mice died, and upon examination, Griffith found live S-strain bacteria in the dead mice.

4. **Conclusion Drawn**: From this experiment, Griffith concluded that some "transforming principle" from the dead S-strain bacteria had transformed the live R-strain into virulent S-strain. This indicated that there was some genetic material responsible for this transformation.

5. **Inference**: The inference drawn from Griffith's transformation experiments is that there is some genetic material responsible for the transformation of non-virulent bacteria into virulent bacteria. This laid the groundwork for the later identification of DNA as the genetic material.

**Final Answer**: The correct inference extracted from Griffith's transformation experiments is: **C. There is some genetic material which is responsible for transformation.**

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