Water: The Solvent of Life (Campbell Biology)
A sugar cube placed in a glass of water will dissolve with a little stirring. The glass will then contain a uniform mixture of sugar and water; the concentration of dissolved sugar will be the same everywhere in the mixture. A liquid that is a completely homogeneous mixture of two or more substances is called a solution. The dissolving agent of a solution is the solvent, and the substance that is dissolved is the solute. In this case, water is the solvent and sugar is the solute. An aqueous solution is one in which the solute is dissolved in water; water is the solvent.
Water is a very versatile solvent, a quality we can trace to the polarity of the water molecule. Suppose, for example, that a spoonful of table salt, the ionic compound sodium chloride (NaCl), is placed in water. At the surface of each crystal of salt, the sodium and chloride ions are exposed to the solvent. These ions and regions of the water molecules are attracted to each other due to their opposite charges. The oxygens of the water molecules have regions of partial negative charge that are attracted to sodium cations. The hydrogen regions are partially positively charged and are attracted to chloride anions. As a result, water molecules surround the individual sodium and chloride ions, separating and shielding them from one another. The sphere of water molecules around each dissolved ion is called a hydration shell. Working inward from the surface of each salt crystal, water eventually dissolves all the ions. The result is a solution of two solutes, sodium cations and chloride anions, homogeneously mixed with water, the solvent. Other ionic compounds also dissolve in water. Seawater, for instance, contains a great variety of dissolved ions, as do living cells.
A compound does not need to be ionic to dissolve in water; many compounds made up of non-ionic polar molecules, such as the sugar in the sugar cube mentioned earlier, are also water-soluble. Such compounds dissolve when water molecules surround each of the solute molecules, forming hydrogen bonds with them. Even molecules as large as proteins can dissolve in water if they have ionic and polar regions on their surface. Many different kinds of polar compounds are dissolved (along with ions) in the water of such biological fluids as blood, the sap of plants, and the liquid within all cells. Water is the solvent of life.
Urry, Lisa A.. Campbell Biology. Pearson Education. Kindle Edition. https://www.pearson.com/us/higher-education/series/Campbell-Biology-Series/2244849.html
Research Article: ESR Study of Interfacial Hydration Layers of Polypeptides in Water-Filled Nanochannels and in Vitrified Bulk Solvents
Date Published: June 28, 2013 Publisher: Public Library of Science Author(s): Yei-Chen Lai, Yi-Fan Chen, Yun-Wei Chiang, Danilo Roccatano. http://doi.org/10.1371/journal.pone.0068264 Abstract: There is considerable evidence for the essential role of surface water in protein function and structure. However, it is unclear to what extent the hydration water and protein are coupled and interact with each … Continue reading
Date Published: April 27, 2016 Publisher: Public Library of Science Author(s): Viviane Forsberg, Renyun Zhang, Joakim Bäckström, Christina Dahlström, Britta Andres, Magnus Norgren, Mattias Andersson, Magnus Hummelgård, Håkan Olin, Vipul Bansal. http://doi.org/10.1371/journal.pone.0154522 Abstract: Many solution processing methods of exfoliation of layered materials have been studied during the last few years; most of them are based … Continue reading
Research Article: The effect of structural properties on rheological behaviour of starches in binary dimethyl sulfoxide-water solutions
Date Published: February 2, 2017 Publisher: Public Library of Science Author(s): Anna Ptaszek, Paweł Ptaszek, Marek Dziubiński, N. Mirosław Grzesik, Marta Liszka-Skoczylas, Xiao-Dong Wang. http://doi.org/10.1371/journal.pone.0171109 Abstract: This research study analysed the rheological properties of potato amylose and potato amylopectin in binary solutions of the following water and dimethyl sulfoxide concentrations: 90% DMSO (1), 80% DMSO … Continue reading
Research Article: Stability and Biological Activity Evaluation of Chlorantraniliprole Solid Nanodispersions Prepared by High Pressure Homogenization
Date Published: August 8, 2016 Publisher: Public Library of Science Author(s): Bo Cui, Lei Feng, Chunxin Wang, Dongsheng Yang, Manli Yu, Zhanghua Zeng, Yan Wang, Changjiao Sun, Xiang Zhao, Haixin Cui, Etsuro Ito. http://doi.org/10.1371/journal.pone.0160877 Abstract: Poorly water-soluble compounds are difficult to develop as pesticide products and face great challenges in water-based and environmentally friendly formulation … Continue reading
Research Article: The Spectral Properties of (-)-Epigallocatechin 3-O-Gallate (EGCG) Fluorescence in Different Solvents: Dependence on Solvent Polarity
Date Published: November 22, 2013 Publisher: Public Library of Science Author(s): Vladislav Snitsarev, Michael N. Young, Ross M. S. Miller, David P. Rotella, Heidar-Ali Tajmir-Riahi. http://doi.org/10.1371/journal.pone.0079834 Abstract: (-)-Epigallocatechin 3-O-gallate (EGCG) a molecule found in green tea and known for a plethora of bioactive properties is an inhibitor of heat shock protein 90 (HSP90), a protein … Continue reading