(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) Explain with the help of Griffith's experiment how the seach for genetic material was conducted and what was the conclusion drawn ? (b) How did Macleod,Mc Carty and Avery establish the Bio-Chemical nature of the so called "genetic material" identified by Griffith in his experiment.

(a) Describe the various steps of Griffith's experiment that led to the conclusion of the 'Transforming Principle'. (b) How did the chemical nature of the 'Transforming Principle' get established ?

In a series of experiments with Streptococcus and mice F. Griffith concluded that R-strain bacteria had been transformed. Explain.

(a) Explain Griffith's series of experiments where he witnessed transformation in bacteria he worked with. (b) Name the scientists responsible for determining the biochemical nature of "transforming principle" in Griffith's experiments. What did they prove?

(a) State Kirchhoff's rules for an electirc network. Using Kirchhoff's rules, obtain the balance condition in terms of the resistances of four arms of Wheatstone bridge. (b) In the meter bridge experimental set up, shown in the figure, the null point 'D' is obtained at a distance of 40 cm from end A of the meter bridge wire. If a resistance of 10 Omega is connected in series with R_(1), null point is obtained at AD = 60 cm. Calculate the values of R_(1) and R_(2).

The velocity distribution of molecules in a beam coming out of a hole in a vessel is described by the function F(v) = A v^3 e^(- mv^2//2 k T) , where T is the temperature of the gas in the vessel. Find the most probable values of (a) the velocity of the molecules in the beam , compare the result obtained with the most probable velocity of the molecules in the vessel , (b) the kinetic energy of the molecules in the beam.

(a) Hershey and Chase carried their experiment in three steps : infection, blending, centrifugation. Explain each step. (b) Write the conclusion and interpretation of the result they obtained.