Which of the following statements are true regarding Griffith’s Experiment?
I. Biochemical nature of genetic material is known.
II. Experimental bacteria is Streptococcus
III. Heat killed virulent bacteria is transformed.
IV. S strain is virulent as it lacks capsule
Which of the following statements are true regarding Griffith’s Experiment?
I. Biochemical nature of genetic material is known.
II. Experimental bacteria is Streptococcus
III. Heat killed virulent bacteria is transformed.
IV. S strain is virulent as it lacks capsule
The correct option is D Only II
During the experiment, Griffith cultured Streptococcus pneumoniae bacteria which showed two patterns of growth. One culture plate consisted of smooth shiny colonies (S) while the other consisted of rough colonies (R). The difference was due to the presence of mucous coat in S strain bacteria, whereas the R strain bacteria lacked them.
Experiment: Griffith injected both S and R strains into mice. The one which was infected with the S strain developed pneumonia and died while that infected with the R strain stayed alive.
In the second stage, Griffith heat-killed the S strain bacteria and injected them into mice, but the mice stayed alive. Then, he mixed the heat-killed S and live R strains. This mixture was injected into mice and they died. In addition, he found living S strain bacteria in dead mice.
Conclusion: Based on the observation, Griffith concluded that R strain bacteria had been transformed by S strain bacteria. The R strain inherited some ‘transforming principle’ from the heat-killed S strain bacteria which made them virulent. And he assumed this transforming principle as genetic material.
The biochemical nature of genetic material is not known from Griffith’s experiment. Virulent bacteria are transformed. S strain is virulent as it has a capsule.
The correct option is D Only II
During the experiment, Griffith cultured Streptococcus pneumoniae bacteria which showed two patterns of growth. One culture plate consisted of smooth shiny colonies (S) while the other consisted of rough colonies (R). The difference was due to the presence of mucous coat in S strain bacteria, whereas the R strain bacteria lacked them.
Experiment: Griffith injected both S and R strains into mice. The one which was infected with the S strain developed pneumonia and died while that infected with the R strain stayed alive.
In the second stage, Griffith heat-killed the S strain bacteria and injected them into mice, but the mice stayed alive. Then, he mixed the heat-killed S and live R strains. This mixture was injected into mice and they died. In addition, he found living S strain bacteria in dead mice.
Conclusion: Based on the observation, Griffith concluded that R strain bacteria had been transformed by S strain bacteria. The R strain inherited some ‘transforming principle’ from the heat-killed S strain bacteria which made them virulent. And he assumed this transforming principle as genetic material.
The biochemical nature of genetic material is not known from Griffith’s experiment. Virulent bacteria are transformed. S strain is virulent as it has a capsule.
