AP BIOLOGY

Detailed explanation-1: -The “Griffith’s Experiment, ” conducted in 1928 by English bacteriologist Frederick Griffith described the conversion of a non-pathogenic pneumococcal bacteria to a virulent strain. In this experiment, Griffith mixed the living non-virulent bacteria with a heat inactivated virulent form.

Detailed explanation-2: -The experiments of Griffith and Avery, MacLeod and McCarty are closely related. Griffith developed the concept of the transforming principle. The prinicple was able to transform a non-pathogenic bacteria into a pathogenic strain.

Detailed explanation-3: -In the 1920s, Frederick Griffith made an important discovery. He was studying two different strains of a bacterium, called R (rough) strain and S (smooth) strain.

Detailed explanation-4: -Frederick Griffith, a British medical officer, studied Streptococcus pneumoniae, a bacteria that causes pneumonia in mice. His work focused on studying two different strains of the virus: a lethal form (virulent) and a non-lethal form (harmless).

Detailed explanation-5: -Griffith concluded that the R-strain bacteria must have taken up what he called a “transforming principle” from the heat-killed S bacteria, which allowed them to “transform” into smooth-coated bacteria and become virulent.