The membrane has a double lipid layer through which fat- soluble substances will
move, by passive transport or diffusion. The molecules will only move through if
hydrophilic. These regions allow water and water soluble substances through, but
substances move through by passive transport or diffusion. Diffusion is the
passive movement of substances from a high concentration to a low concentration
( N.B., you don’t need a membrane present, e.g. diffusion occurs in the air). In
CONTRAST, diffusion of water across a semi- permeable membrane is called
molecule on the outside, which requires ATP. It then moves across, (which also
transport by insulin. Why is it called the Fluid Mosaic Model? Fluid- it is
fluid) Mosaic- it is a mosaic because it is a collection (or mosaic) of
structures Model- because no matter how real the diagram looks, it is not real.
Therefore, it is a model. SO you put all three bits together and you get.