The water molecule itself is comprised of a single oxygen atom and two hydrogen atoms. It is the attractions between these atoms however that give water one of its most important features. Whilst covalent bonds do form to keep the three atoms together, their proximity to one another leads to an uneven arrangement of electrons. This leads to the two hydrogen ends becoming slightly positively charged, with the oxygen atom becoming slightly negatively charged. The difference in charge means that water is described as a dipolar molecule. Water’s polarity, when combined with its abundance, means that it is often described as the ‘universal solvent’. With the exception of non-polar molecules, all polar and ionic substances will form weak hydrogen bonds with water molecules, thus forming a solution. This is important as many of the chemical reactions which take place within both plant and animal cells use water as a solvent. Without it, these reactions would not be able to take place and many organisms would not be able to survive. The polarity of water is also used to transport substances through plants. Cellulose, which makes up plant cell walls, will form strong hydrogen bonds with the water molecules but crucially will not dissolve in it due to it being a non-polar substance. The hydrogen bonds created mean that there is a strong adhesion between the water and the cell walls. If there is a large enough volume of water the bonds between the water molecules will attract each other in a certain direction, whether this be up or down inside the xylem vessels. Solutes needed for different processes within the plant such as growth will be dissolved in the water, meaning that they too will be transported through the movement of the water molecules through the xylem into the different areas of the plant.