Question

PLEASE ANSWER FULLY!

How are Lk (linking number), Tw (twist), and Wr (writhe) inter-related? How many based pairs per turn in relaxed DNA, positively and negatively supercoiled DNA? What is the biological significance of supercoiling? When does it occur? Is it a good thing or a bad thing? What enzymes are involved in changing DNA topology, and what is their mode of action?