analysis of plasmid pbr322

[messi19]

hi got a couple of questions regarding the plasmid.

1)From the photograph determine the migration distances (in mm) of the molecular weight standard DNA bands and of the bands of pBR322 cut with the different enzymes and construct a table with this data.
2) Construct a standard curve (graph) of migration distance versus log molecular weight (in base pairs - bp) for the molecular weight standard bands plotting log10 marker fragment size (bp) against distance of fragment migration. Use the standard curve to determine the size of your pBR322 fragment bands from all the different combinations of enzymes - in Lanes 2-4 – and confirm the size of pBR322 for the
single enzyme digests Lanes 5-7. Present your data in tabular form appropriately labelled.



I did a graph using the standard bands and the distance they migrated against the log . then i interpolated the points i had from lanes 2-7 and worked out the log for them. i did the inverse of log which i presume gives me the fragment size in bp. for e.g 56mm was distance migrated, its log was 3.5 therefore its antilog was 3162.( which is the base pairs.correct if im wrong please) it is the next 2 questions that i am having trouble with.

the size of the pbr322 is the sum of the fragments. i already have this information but im not sure which pieces of data i am adding up. its not the log so therfore would be the antilog? if so which points am i adding up.

3) What is the size of pBR322? How did you work this out from your results?
4) Using the data you have generated. Draw a representation of the plasmid showing the relative positions of the three restriction endonuclease sites.