Hello,

I am working on the practice exam for spiker's class and I really need some help. On #24 I can't figure out how you are supposed to figure out the number of supercoils and so forth.
This is the problem just in case someone else knows how to answer it:
Suppose RNA polymerase is transcribing DNA in a topologically isolated loop domain. the 800bp stretch of DNA behind the polymerase is completely unwound and has no supercoils. Under these conditions you would expect supercoils to form. Answer these questions about this 800bp region:
Would you expect the supercoils to be right handed or left handed?
How many supercoils would you expect to form?
After the supercoils had formed, what would be the value of the twist?
What is the linking number for this stretch of DNA?
What would be the ideal (relaxed) linking number?

I'm guessing for the last question, it is 80 because 800bp / 10bp/turn would be the best relaxed state. Other than that, I am not sure how we are supposed to go from there. Any help would be great, I just want to understand how to work this. I went to the review, but I think I may have missed the very beginning when he went over this problem. Thanks!

9/21/2006 3:31:50 PM