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.
Confidence votes 355. DNA helicase unzip, or separate, a strand of DNA at positions called origins. This means that the hydrogen bonds between complementary base pairs are removed (DNA is double stranded!). When they separate double-stranded DNA into single strands, it allows each strand to be copied (replication).