IntroductionWater, H2O, is one of the most important chemical compounds on earth and is commonly referred to as the basis of life on earth, because it is used in all types of chemical and biological processes, e.g. solvent, protein folding, nucleic acid stability, etc. Water comes in 3 states (solid, liquid and gas) and is the most abundant natural substance on earth, covering 75% of the planet. the surface of the earth.StructureWater consists of 2 hydrogen atoms and 1 oxygen atom (held together by covalent bonds between the OH atoms) and 2 pairs of free electrons on the oxygen atom, which results in the formation of a curved shape with a bond angle of 104.5⁰. These 2 free electron doublets mean that water has a tetrahedral structure where oxygen is linked to 4 hydrogen atoms; 2 covalent bonds and 2 hydrogen bonds (General Chemistry, 2011). The hydrogen bond "is a specific type of dipole-dipole interaction between the hydrogen atom in a polar bond and an electronegative O, N, or F atom" (Quotes from General Chemistry, 2011 page 405), and is the type of the most powerful intermolecular force. Hydrogen bonds in water (Figure 1) mean that water has a high specific heat capacity, because, because hydrogen bonds are strong, a large amount of heat (increasing the kinetic energy of water molecules) is necessary to break them. can absorb a large amount of heat and its temperature increases only slightly, and it is the opposite when heat is released, that is, its temperature only decreases slightly (General Chemistry, 2011) . The presence of hydrogen bonds between water molecules, allowing them to stick together, shows that water is very cohesive (Biochemistry, 2011). A special type of cohesion is surface tension, in which te...... middle of paper ......ical Societyhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC372788/pdf /microrev00039-0112.pdfhttp://www.ncbi.nlm.nih.gov/pubmed/3307919http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1262463/pdf/biophysj00088-0020.pdfhttp:/ / www.lsbu.ac.uk/water/protein2.html - Protein folding and denaturation http://www.lsbu.ac.uk/water/protein.html - Protein hydration http://www.lsbu.ac .uk/water/ nucleic.html - Nucleic acidhttp://www.biomedcentral.com/1471-2199/12/21 - Protein diversityhttp://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=4335444 – Behavior of waterhttp://www.exobiologie.fr/index.php/vulgarisation/église-vulgarisation/the-role-of-water-in-the-structure-and-function-of-biological-macromolecules/ - The role of water in the structure and function of biological macromoleculesWikipedia – Protein folding, Water, Hydrophobic interactions, Solvent