Water is an Important Component of Cells

Water is an important component of cells Life began with the presence of water, so that all organisms are mostly composed of water and live in an environment dominated by water. Cells contain 75% to 90% water which is also in the water environment medium. Water is the only substance that can be found in nature in three different physical states of matter: liquid, solid and gas. Each water molecule can form hydrogen bonds with a maximum of four molecules around it. The extraordinary quality of water is that it arises as a result of hydrogen bonds that can organize these molecules into higher levels of structural arrangement. Water is the main medium that is very important for cells, because each cell will definitely be surrounded by cytosol (intra-cell fluid with the main medium being water) and extra-cell fluid which contains materials needed by the cell and a place to accommodate the results of cell secretions. The presence of water plays an important role in the environment with its four main properties, namely: 1) cohesive behavior, 2) ability to stabilize temperature, 3) expansion when frozen, and 4) the importance of water as a solvent. Cohesive behavior of water Water molecules stick together because of weak hydrogen bonds that are easily separated and quickly re-formed between the molecules. These conditions make water more orderly than other liquids, which together is a phenomenon called cohesion. In plants, cohesion plays a role in transporting water against gravity, where hydrogen bonds cause every water molecule that comes out to be able to continuously attract water molecules in the vessels. The binding of water to the vessel walls which also helps fight gravity is called adhesion. An important condition that is closely related to cohesion is the presence of surface tension, which is a measure of how difficult it is for the surface of a liquid to be stretched or broken. Ability to stabilize temperature The existence of water is very essential on earth, with various functions. Water is able to stabilize air temperature by absorbing heat from warmer air and then releasing it to cooler air. One of the cooling processes using water is through the evaporation mechanism. For example, the evaporation of water from plant leaves will help the tissues in the leaves not get too hot in the sun. The process of sweating will reduce body heat and help prevent overheating during hot weather or when excess heat is produced due to high activity. The high heat of evaporation of water helps stabilize the climate on earth. A large amount of solar heat is absorbed by tropical oceans and used in the evaporation of water on the surface of these oceans. Then, the humid tropical air rotates towards the poles and heat energy is released when the moist air condenses to form rain. When a liquid evaporates, the surface of the liquid that has not evaporated will remain cool. This process of cooling water through evaporation plays a role in stabilizing the temperature in lakes and ponds and provides a mechanism that can prevent land organisms from overheating. Expansion when frozen Water is a substance whose liquid state is denser than its solid state, so that when other objects shrink when solidified, water will expand into ice when solidified. This unique thing occurs because of the hydrogen bonds in water, which begins to freeze when the molecules move slowly so that they are unable to break their hydrogen bonds due to the decrease in temperature. When the temperature is 0ᴼC, each molecule will bond with a maximum of 4 other water molecules, and maintain these molecules at a fairly long distance. The ability of ice to float due to the expansion of water when compressed is important for environmental sustainability. The ice will cover the liquid water beneath it and prevent it from freezing, thereby maintaining life beneath the frozen surface of the ice. Water as solvent Water as a solvent around cells, with many chemical elements will affect their biochemical mechanisms. A compound does not need to be an ionic compound to be soluble in water, because polar compounds are also compounds that dissolve in water. A large molecule, such as a protein, can dissolve in water if it has both ionic and polar regions on its surface. Various types of polar compounds can be dissolved (along with their ions) in water which is biological fluids, such as blood, plant juices, and intracellular fluids. Many biomolecules will interact with water, where the presence of water can provide conditions described as hydrophilic and hydrophobic, and even amphipathic conditions for certain biomolecules (such as phospholipids) can consist of two hydrophilic and hydrophobic conditions. All substances that have the highest affinity, whether ionic or polar, is called hydrophilic. For example, sugar which has polar properties can dissolve in water because the water molecules can cover the polar molecules of the sugar. Meanwhile, non-ionic and non-polar compounds will definitely repel water and are called hydrophobic. An example is vegetable oil which cannot be dissolved and mixes with substances containing water such as vinegar. The hydrophobic condition of the oil occurs because of the bonds between carbon and hydrogen which share their electrons almost equally. The overall function of cells, tissues and organisms depends on all interacting molecules from the smallest to the largest. Life is very dependent on thousands of chemical interactions and reactions, each of which chemical components correctly and appropriately will bind to one another at one place and time so that it will influence the genetic instructions of cells and their environment.