The Graphite Experiment

Study Notes

Frederick Griffith's Graphite Experiment on Tryptococcus Pneumonia

Frederick Griffith, a British medical officer, conducted an experiment in 1928 on the bacterium Tryptococcus Pneumonia.
Tryptococcus Pneumonia is a bacterium that causes pneumonia in humans and other mammals.
There are two strains of Tryptococcus Pneumonia: S strain and R strain.
The S strain has a polysaccharide coat, making it virulent, pathogenic, and encapsulated.
The R strain is non-virulent, non-pathogenic, and non-capsulated.
Griffith performed four experiments using these bacteria.
In the first experiment, he injected the R strain into mice, and the mice did not suffer from pneumonia and survived. This was because the R strain does not have a polysaccharide coat that can be destroyed by the mice's immune system.
In the second experiment, Griffith injected the S strain into mice, and the mice developed pneumonia and died. This was because the S strain's polysaccharide capsule protected it from destruction by the mice's immune system.
In the third experiment, Griffith heated the S strain, which killed it.
In the fourth experiment, Griffith injected a mixture of the heat-killed S strain and the live R strain into mice.
Surprisingly, the mice developed pneumonia and died, and when Griffith examined their bodies, he found live S strain bacteria.
This led to the discovery of transformation, where the genetic material from the heat-killed S strain was taken up by the live R strain, transforming it into the S strain.
This experiment provided important evidence for the concept of genetic transformation in bacteria.

Description

Test your knowledge on the Graphite Experiment conducted by Frederick Griffith in 1928. Explore the details of the experiment, including the two strains of diplococcus pneumonia and their characteristics. Challenge yourself with questions about strain S and strain R, and their significance in causing pneumonia in humans and mammals.