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Question
In Griffith experiments, what happened when heat-killed S strains pneumococci were injected into a mouse along with live R strains pneumococci ?
In Griffith experiments, what happened when heat-killed S strains pneumococci were injected into a mouse along with live R strains pneumococci ?
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Solution
The correct option is B DNA from the heat-killed S was taken up by the live R converting it to S and killing the mouse
In Griffith's experiment, the mice were injected by both S (smooth Streptococcus) and R (rough Streptococcus) strains of the bacteria.
1) S strain → Injected into mice → Mice developed pneumonia and die.
2) R strain → Injected into mice → Mice live.
3) Heat-killed S strain → Injected into mice → Mice live. (heat kills the bacteria).
4) Heat-killed S strain + R strain → Injected into mice → Mice die.
DNA, RNA and proteins were extracted from the heat-killed S strain bacteria. The treated heat-killed S strain mixed with proteases to break down proteins and were also treated the strain with RNAses and then DNAses to break down RNA and DNA molecules respectively. The treatment of the S-strain with the protease and RNAse treatments did not affect the transformation of the R strain into the virulent one. The treatment with DNAses inhibited the transformation of the R strain thus, it was concluded that DNA was the genetic material.
Therefore, the correct answer is option 'b'.
In Griffith's experiment, the mice were injected by both S (smooth Streptococcus) and R (rough Streptococcus) strains of the bacteria.
1) S strain → Injected into mice → Mice developed pneumonia and die.
2) R strain → Injected into mice → Mice live.
3) Heat-killed S strain → Injected into mice → Mice live. (heat kills the bacteria).
4) Heat-killed S strain + R strain → Injected into mice → Mice die.
DNA, RNA and proteins were extracted from the heat-killed S strain bacteria. The treated heat-killed S strain mixed with proteases to break down proteins and were also treated the strain with RNAses and then DNAses to break down RNA and DNA molecules respectively. The treatment of the S-strain with the protease and RNAse treatments did not affect the transformation of the R strain into the virulent one. The treatment with DNAses inhibited the transformation of the R strain thus, it was concluded that DNA was the genetic material.
Therefore, the correct answer is option 'b'.
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