Question

Choose the correct answers from the alternatives given :
In his work with pneumonia-causing bacteria and mice, Griffith found that

• A. polysaccharide coat of R cells caused pneumonia
• B. some heat-stable chemical from S cells was transferred to R cells to transform them into S cells
• C. heat-killed S cells were able to cause pneumonia only when they were transformed by the DNA of R cells
• D. the protein coat from smooth (S) cells was able to transform rough (R) cells

Answer 1

The correct option is B some heat-stable chemical from S cells was transferred to R cells to transform them into S cells

Friedrick Griffith discovered the process of transformation. He performed an experiment on mice using pneumonia-causing bacteria. The R strain had a rough texture and did not cause the disease while S strain had a smooth texture which was responsible for its disease-causing capability.

When the S strain was heat killed, it became dormant and did not cause the disease. At last, Griffith injected a combination of R strain with heat-killed S strain. In this case, the disease should not have been caused but the mice died. He found some live S strain. Therefore, he concluded that R strain picked up some heat stable chemical from S strain and got transformed.

So, the correct option is 'some heat-stable chemical from S cells was transferred to R cells to transform them into S cells'.