Interesting question....

[khushi]

A bizzare organism was isolated from deep space probe and found its cellular components very similar to terrestrial organism.when the organism was examined using the meselson stahl experiment only bands of heavy DNA were isolated in repetitive cell divisions.The organism appeared to have all the types of nucleic acid polymerases and other enzyme but was found lacking pol 111.An enzyme of unknown function necessary for DNA replication that required NADPH as a cofactor was isolated from the organism.Devise a scheme of DNA replication which is consistent with these observation.Basically we can not use DNA as a template.

We have to degrade original DNA.

[blcr11]

That's your scheme? to degrade the DNA? Not meaning to ridicule anyone, but how is that supposed to work? God pity the poor organism forced to live that way. The Messelsen-Stahl experiment was designed to rule out two of three possible mechanisms for DNA replication. You might want to consider one of the two mechanisms Messelsen-Stahl ruled out. You might also want to consider that they didn't know too much about RNA in the days of those early replication experiments. If you put the two together--and perhaps there is more than one way to do this, I don't know; I can see one way it might be done--you can come up with a better scheme that "degrading the DNA." Stop and think for a moment how you might go from RNA to DNA, for example.