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प्रश्न
Who revealed biochemical nature of the transforming principle? How was it done?
उत्तर
Prior to the work of Oswald Avery, Colin MacLeod and Maclyn McCarty (1933 - 44), the genetic material was thought to be a protein. They worked to determine the biochemical nature of ‘transforming principle’ in Griffith’s experiment. They purified biochemicals (proteins, DNA, RNA, etc.) from the heat-killed S cells to see which ones could transform live R cells into S cells. They discovered that DNA alone from S bacteria caused R bacteria to become transformed.
They also discovered that protein-digesting enzymes (proteases) and RNA-digesting enzymes (RNases) did not affect transformation, so the transforming substance was not a protein or RNA. Digestion with DNase did inhibit transformation, suggesting that the DNA caused the transformation. They concluded that DNA is the hereditary material, but not all biologists were convinced.
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संबंधित प्रश्न
Answer the following questions based on Hershey and Chases's experiments:
(a) Name the kind of virus they worked with and why?
(b) Why did they use two types of culture media to grow viruses in ? Explain.
(c) What was the need for using a blender and later a centrifuge during their experiments?
(d) State the conclusion drawn by them after the experiments.
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Give one significant contribution of the given scientists
H. Boyer
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How has the use of Agrobacterium as vectors helped in controlling Meloidegyne incognitia infestation in tobacco plants? Explain in correct sequence.
(a) Why did Hershey and Chase use radioactive 32P and 35S in their experiments? Explain.
(b) Following the experiments conducted by them, write what conclusion did they arrive at and how ?
Hershey and Chase experiment with bacteriophage showed that ____________.
Name the scientist who proved experimentally that DNA is the genetic material ______.
Define transformation in Griffith's experiment. Discuss how it helps in the identification of DNA as the genetic material.
Griffith conducted a series of experiments on mice with two different strains of the bacterium Diplococcus pneumoniae.
- Describe the entire procedure for this experiment.
- Write the conclusion of this experiment.
- What would have been the result of the experiment if both strains of bacteria were first heat-killed, mixed and then injected in the mice?
