Water is very important in all living organisms, it is vital for many different things. Around 70% of our body weight is due to water. The quantity is high in organs such as lungs and brain and fluids such as blood, lymph, saliva and secretions by the organs of the digestive system.
First of all water is vital in the regulation of body temperature to depending on the temperature mammals will alter the amount they sweat. If they are to warm the amount of seat will increase. Sweat reduces the body temperature because as it evaporates off the skin it cools the surface. If body temperature rises above 37 then enzymes will begin to not function properly and reactions will slow. This is because the enzymes are becoming denatured as their hydrogen bonds break and shape change. This is also relevant in plants. When water is evaporated of leaves of the plant it cools it in the same way. This is also important as plants need to be a certain temperatures so that. Plants need to be at the correct temperature so reactions take place at the fastest rate and so they grow as much as possible. This is especially important in crops and agriculture Also for plants to grow at the fastest possible rate they have to have the correct amount of water.
Water is also important because without osmosis wouldn’t occur, so many important particles and nutrients wouldn’t be moved around the organism. An example of this is in the root hair cell. In the soil outside the root hair cell is a higher water potential than in the root. This is because the root hair cell has amino acids, minerals and sugars inside them. So water moves down the concentration gradient into the roots.
The uptake of water in plant cells creates pressures against the rigid walls. This can also help non-woody plants stay upright. Water is pulled up the stem by transpiration pull which creates a negative pressure this causes the water molecules to stick together. Which is called cohesion tension theory. The water is transported up to the leaves and into the chlorophyll where it is used in photosynthesis. Other nutrients and molecules are transported by the water and used in different parts of the plant. Water is also used in the light dependent reaction of photosynthesis. Electrons are lost from the chlorophyll as they get excited and move done carriers. These electrons need to be replaced; this is done by the photolysis of water. The replacement of these electrons are provided from water molecules which are split using light energy.
Water → protons + electrons + oxygen As well as in plants water is important in the body. Water is the medium in which various enzyme and chemical reactions take place. It moves nutrients, hormones, antibodies and oxygen through the blood stream and lymphatic system. Also inside the body many larger molecules need to be broken down, water is used to do this. Polysaccharides are joined by glycosidic bonds. These can be broken by the process of hydrolysis, the addition of water. This splits the polysaccharides into monosaccharides. One reason this is done is so polysaccharides can be hydrolysied into soluble sugars. An example is Cellulose is first hydrolyzed to cellobiose by cellulase and then cellobiose is further hydrolyzed to glucose.
Hydrolysis is an exothermic reaction. It gives off heat as it breaks the glycosidic bonds. This can be used to regulate body temperature, which is very important for the survival of mammals. If it is cold the amount of metabolic reactions will increase. Hydrolysis occurs in the early stage of respiration. Hydrolysis occurs in glycolysis. Energy is needed to activate glucose and energy comes from the hydrolysis of ATP to ADP. Water is vital for metabolic reactions. And if the body is kept at the correct temperature then many processes and reaction will not be carried out correctly. For example body temperature is 37. This is the optimum temperature for enzymes in the body. If that temperature drops the rate at which the reactions involving theses enzymes take place will drop as well.
Courtney from Study Moose