1. Griffith’s work on Pneumococcus

2. Frederick Griffith (1920) was a medical officer in London. He was looking for a way to fight pneumonia in the epidemics after World War I. The discovery was made as he heated to 60°C instead of 100°C, killing the pneumococcus bacteria but not destroying their DNA. This scientist changed genetics. pneumococcus bacteria

3. Pneumococcus bacteria - a kind of Streptococcus bacteria - cause severe pneumonia, meningitis, septicaemia, and ear infections.

5. Rough form of Pneumococcus Smooth form of Pneumococcus

7. What was Griffith ’ s experiment about?

9. After the experiment, Frederick Griffith drew out two hypotheses : 1.The dead S strain had been reanimated/resurrected. 2.The Live R had been transformed into Live S by some "transforming factor" Transformation Principle

10. Further experiments led Griffith to conclude that number 2 was correct. In 1944, three other scientists revisited Griffith's experiment and concluded the transforming factor was DNA. Helix structure of DNA

11. - The End -