Molecular Basis Of Inheritance Question 14
Question: From the experiments carried out by Avery, Macleod and McCarty by using various enzymes, which of the following results prominently proved that DNA is the transforming material?
Options:
A) DNA of heat killed ‘S’ + R type + DNAase $ \to $ virulent strain
B) DNA of heat killed ‘S’+R type + RNAase $ \to $ virulent strain
C) DNA of heat killed’ S’ + R type $ \to $ virulent strain
D) DNA of heat killed ‘S’+R type + Protease $ \to $ virulent strain
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Answer:
Correct Answer: C
Solution:
[a] Heat-killed S-type bacteria caused a transformation of the R-type bacteria into S-type bacteria but he was not able to understand the cause of this bacterial transformation.
The occurrence of living 19 S-type virulent bacteria is possible only by their formation from R-type non-virulent bacteria, which pick up the trait of virulence from dead bacteria.
This phenomenon is called Griffith effect or transformation.
Griffith proposed that a chemical substance released by heat killed bacteria changed the R-bacteria into S-bacteria which was a permanent genetic change.