a) Write the conclusin drawn by Griffith at the end of his experiment with Streptococcus pneumoniae.
b) How did O.Avery, C.MacLeod and M. McCarty prove that DNA was the genetic material? Explain.

How did Hershey and Chase proved that DNA is the hereditary material? Explain their experiment with suitable diagram.

How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?

What is meant by R-cells and S-cells with which Frederick Griffith carried out his experiments on Diplococcus pneumoniae? What did he prove from these experiments?

Define transformation in Griffith's experiment. Discuss how it helps in the identification of DNA as the genetic material.

Recell the experiments done by frederick Griffith, Avery, MacLeod and McCarty, where DNA was speculated to be the genatic material. If RNA , instead of DNA was the genetic meterial, would the heat killed strain of pneumoccus have transformed the R-strain into virulent strani? Explain.

(a) Describe the series of experiments of F. Griffith. Comment on the significance of the results obtained. (b) State the contribution of Macleod, McCarty and Avery.

(a) Describe the series of experiments of F. Griffith. Comment on the significance of the results obtained. (b) State the contribution of Macleod, McCarty and Avery.

Explain the experiment performed be Griffith on Streptococcus pneumonia. What did he conclude from this experiment? Name the three scientists who followed up Griffith's experiments. What did they conclude and how?

Answer the following questions based on Meselson and Stahl's experiment of E. coli : (a) Write the name of the chemical substance used as the only source of nitrogen in the experiment. (b) Why did they allow the synthesis of the light and the heavy DNA molecules in the organism ? (c ) How did they distinguish the heavy DNA molecules from the light DNA molecules? Explain. (d) Write the conclusion the scientists arrived at, at the end of the experiment.

Answer the following questions based on Meselson and Stahl s experiment: (a) Write the name of the chemical substance used as a source of nitrogen in the experiment by them. (b) Why did the scientists synthesise the light and the heavy DNA molecules In the organism used in the experiment ? (c) How did the scientists make it possible to distinguish the heavy DNA molecule from the light DNA molecule ? Explain. ((1) Write the conclusion the scientists arrived at after completing the experiment.