Osmosis is the movement of water molecules through a partially permeable membrane. Water molecules move from a region of of higher concentration to an area of lower concentration. When concentration is equal on both sides, there will be no net movement of water molecules. This means that the movement of water molecules will be the same in both directions. Osmosis occurs in all living cells as the cell membrane is partially permeable . Water is able to move in and out of the cell via osmosis. Within the cell there will be various solutes such as amino acids, sugars and ions which affect the level of water needed within the cell, in order for it to maintain its shape.