 One vital role of facilitated diffusion is that it is the main mechanism behind the binding of Transcription Factors (TFs) to designated target sites on the DNA molecule.The in vitro model, which is a very well known method of facilitated diffusion, that takes place outside of a living cell, explains the 3-dimensional pattern of diffusion in the cytosol and the 1-dimensional diffusion along the DNA contour.After carrying out extensive research on processes occurring out of the cell, this mechanism was generally accepted but there was a need to verify that this mechanism could take place in vivo or inside of living cells.