Biological Importance of Water

551 Words3 Pages
The biological importance of water Water is an essential compound for life on Earth which makes up oceans covering 70% of our planet and it makes up around 65% of all living organisms. Water is a liquid at room temperature and water molecules are able to form hydrogen bonds with other water molecules and compounds which makes it a good solvent for everyday use. Salts, sugars and amino acids will dissolve readily in water. It is used in blood to transport substances such as glucose and other soluble nutrients and removes excretory products such as urea which is poisonous. Water is a dipolar molecule which means it attracts other polar molecules by forming hydrogen bonds. Water possesses adhesive properties which makes it group together and stick to other polar substances. Being transparent and colourless, water transmits sunlight which enables plants to photosynthesise and produce their own food(carbohydrates). Water exists in 3 states of matter: solid(ice), liquid(water) and gas(vapour). It has a freezing point of 0°C and a boiling point of 100°C. Water is needed for all hydrolysis reactions i.e. the splitting of a large molecule into a smaller molecule by using water to split the bonds joining the monomers together. This is an important reaction in the process of digestion. As an example, the sugar in milk, lactose(disaccharide), is hydrolysed into its constituent monosaccharides - glucose and galactose. This enables the smaller, simpler molecules to be absorbed by the bloodstream and assimilated into the body. Hydrolysis is required for the breakdown of lipids to fatty acids and glycerol as well as proteins into amino acids. Water is also given out during condensation reactions when a large molecule is being made. Osmosis involves the movement of water from a region of high water potential to a region of low water potential across a partially permeable
Open Document