Question

Oswald et. al showed that when DNAse was added to R and S strain bacteria, S cells survived, suggesting that R cells passed on their DNA to S cells, and DNA is the transforming principle. (T/F)

Answer 1

The statement by the student is false. Oswald Avery and his colleagues demonstrated that DNA is the transforming principle through a series of experiments that involved degrading various molecules and observing the inability to transform R-strain bacteria when DNA was degraded.

Step-by-step explanation:

The statement given by the student incorrectly identifies the scientists and the outcome of the experiments. The correct information is that scientists Oswald Avery, Colin MacLeod, and Maclyn McCarty showed in 1944 that DNA is the transforming principle. Their experiments involved the systematic degradation of molecules such as proteins, RNA, and DNA in the S strain of Streptococcus pneumoniae to determine which molecule was responsible for hereditary transformation.

When DNAse was added to break down DNA, the R strain of bacteria could no longer be transformed into the pathogenic S strain, suggesting that DNA — not protein — is the molecule responsible for heredity. This conclusion was built upon Frederick Griffith's earlier experiments in 1928 that determined there was a transforming principle capable of transferring hereditary information horizontally, but did not identify the molecule responsible.