Think of The FITT principle as a set of rules that must be adhered to in order to benefit from any form of fitness training program.These rules relate to the Frequency, Intensity, Type and Time (FITT) of exercise...gain, intensity has a say and particularly grueling strength sessions may last as little as 20 - 30 minutes. Perhaps the most important principle of training (that ironically doesn't have it's own letter in the FITT principle) is rest.
Scientists knew the DNA could be uncoiled from the nucleosome, but it was assumed that the two ends were symmetric, meaning uncoiling the DNA would be like untying a shoe. University of Illinois researchers found that the DNA is actually very asymmetric, like the string wrapped around a yoyo.
DNA is generally tightly packed into a structure called chromatin. It is double stranded and twisted into a structure called a double helix. In order to replicate, DNA must unwind. After unwinding, each side of DNA separates by unzipping down the middle, with the two unzipped strands serving as templates for creating new strands.