Answer:
In osmosis, molecules cross the cell's plasma membrane to achieve equilibrium.
Step-by-step explanation:
A bilipid layer called a plasma membrane typically surrounds cells. Here, lipid molecules are arranged tail-to-tail, with their heads facing outwards. The heads of the lipids, are water soluble, while the tails are insoluble. Proteins and cholesterol also help maintain membrane fluidity.
With the use of its transport proteins, pores and gated channels, embedded among the lipids the membrane maintains its concentration of substances through selective permeability.
Simple diffusion occurs in cells through plasma membranes as a means of passive transport. In osmosis, molecules of water move across the membrane, down their concentration gradient- i.e. they try to balance their concentration or number of water particles.
The water particles move from regions of high concentration to regions of low water concentration. Typically these 'destinations' or regions have large amounts of solute which contributes to the formation of this gradient.