Avery et al. conducted experiments showing that DNA is the genetic material because which outcome occurred when DNA was destroyed?

Avery et al. conducted experiments showing that DNA is the genetic material because which outcome occurred when DNA was destroyed?

• A. Transformation did not occur
• B. Transformation occurred more rapidly
• C. Protein synthesis stopped
• D. RNA synthesis stopped

Answer: (A)

Transformation is the process by which a bacterium takes up external genetic material and changes its phenotype. In the Avery–MacLeod–McCarty experiments, they showed that when the material responsible for transformation was destroyed, the transformation did not occur. Specifically, destroying DNA with DNase prevented the avirulent R cells from becoming encapsulated and virulent, so the R cells did not undergo transformation. In contrast, destroying protein or RNA did not stop transformation, indicating those molecules were not carrying the genetic instruction in this context. This is why the outcome when DNA was destroyed is that transformation did not occur, pointing to DNA as the genetic material.

Transformation is the process by which a bacterium takes up external genetic material and changes its phenotype. In the Avery–MacLeod–McCarty experiments, they showed that when the material responsible for transformation was destroyed, the transformation did not occur. Specifically, destroying DNA with DNase prevented the avirulent R cells from becoming encapsulated and virulent, so the R cells did not undergo transformation. In contrast, destroying protein or RNA did not stop transformation, indicating those molecules were not carrying the genetic instruction in this context. This is why the outcome when DNA was destroyed is that transformation did not occur, pointing to DNA as the genetic material.