Water is a polar solvent because water molecules have partial charges.Water can therefore act as a solvent for many molecules needed for cellular functions.The cytosols of both prokaryotic and eukaryotic cells are mainly water. Water dissolves amino-acids, proteins, simple sugars and many molecules helps transport dissolved substances in and out of cells.Blood plasma is mostly water. It transports substances such as glucose and cells such as red blood cells and white blood cells around the body as it is a liquid at body temperature.Water is also used in the phloem to transport dissolved sucrose made in photosynthesis around plants.