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Describe the experiments that established the identity of ‘transforming principles’ of Griffith.
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Griffith experiment was a stepping stone for the discovery of genetic material. Frederick Griffith experiments were conducted with Streptococcus pneumoniae.
During the experiment, Griffith cultured Streptococcus pneumoniae bacteria which showed two patterns of growth. One culture plate consisted of smooth shiny colonies (S) while 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 to 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 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.
During the experiment, Griffith cultured Streptococcus pneumoniae bacteria which showed two patterns of growth. One culture plate consisted of smooth shiny colonies (S) while 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 to 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 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.
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Question Text | Describe the experiments that established the identity of ‘transforming principles’ of Griffith. |
Topic | Molecular Basis of Inheritance |
Subject | Biology |
Class | Class 12 |
Answer Type | Text solution:1 |
Upvotes | 79 |