a change in genotype and phenotype due to asimilaiton of external DNA by a cell
Experiment: can a gentic trait be transferred between different bacteria?
Frederick Griffith. Injected living S cells (pathogenic), living R cells (nonpathogenic), heat killed S cells and a mix of heat killed S cells and living R cells. Living S cells and mixed mice died. Concluded living R bacteria was transformed into pathogenic S bacteria
viruses that infect bacteria
Experiment: is protein or DNA the genetic material?
Alfred Hershey and Martha Chase used radioactive sulfur and phosphorus to trace the fates of protein and DNA. Results: phage DNA entered bacteria (radioactive labeled DNA was seen inside cell) protein remained outside.
The equivalences for any given species between the number of A and T bases and the number of G and C bases
replicated double helix consists of one old strand derived from the old molecule and one newly made strand