Question

In an invitro exprement using radiolabelled necleotides, a researcher is trying to analize the possible products of replication by resolving the products using urea polyacrylamide gel electrophoresis. in one exprimental setup RNAse H was added and while in another set no RNAse h was added. what will be the possible outcome of the two gels result?

Answer 1

I think this question is trying to get at the function of RNAseH, so I'lltry to get you started on this process: the "H" stands for hybrid, so the enzyme will chew up any RNA that's in a hybrid between DNA and RNA. This means that the primer sequences won't work and so there will be no incorporation of radiolabel into the strands since no nucleotides are being used to make longer strands.

In the experiment without any RNaseH things will be a bit more normal and so there will be a long strand (called the leading strand) and several shorter ones (Okazaki fragments). Have a look here for more details and some nice pictures:
http://en.wikipedia.org/wiki/DNA_replication

Answer 2

The radiolabelled nucleotides should be incorporated evenly throughout the genome during normal replication. As ebaxter said, RNase H only digests RNA that has been incoporated into a DNA/RNA hybrid and will not digest DNA or any un-hybridized RNA. This is useful when the small RNA primers need to be removed during DNA replication so that DNA polymerase can fill the gap with DNA.

In the experiment with RNase H, newly synthesized stands will have a stronger signal due to a larger amount of radiolabelled nucletides being integrated due to the excision of the RNA primers. Also, the bands should reside higher on the gel due to their longer, continuous length.

Without RNase H, the RNA primers will never be removed, leaving small fragments as mentioned above. These fragments will run lower on the gel as well as having a lower radioactive intensity.