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 base flipping, or nucleotide flipping, is a mechanism in which a single nucleotide base, or nucleobase, is rotated outside the nucleic acid double helix. [1] This occurs when a nucleic acid-processing enzyme needs access to the base to perform work on it, such as its excision for replacement with another base during DNA repair. It was first observed in 1994 using X-ray crystallography in a methyltransferase enzyme catalyzing methylation of a cytosine base in DNA.