What you really need to know about water’s chemistry
Water is physiology’s most important chemical. The chemical properties of water continue to be an active area of scientific research. Scientists are still discovering unique aspects of water’s molecular nature when it is confined to biologic spaces. If you are interested in the details, examples of such studies are found at Science 328, 985 (2010) and Science 336, 897 (2012) in your library.
How did the word ‘chemical’ get such a bad reputation?
Plain old, one hundred percent pure, ordinary water is an important chemical. There is a lot of confusion in the popular press about what constitutes a chemical. Even chemistry textbooks have been known to define chemical substances as “any material with a definite chemical composition.”
Much of what we read in product ads misleads us about the definition of a chemical. “Chemical-free” is used in advertising to imply the safety of a product. It leaves us with the impression that there is something not natural and bad about chemicals.
Actually, the word chemical is a synonym for matter. Matter makes up the universe. Humans, being part of the universe, are made up of chemicals. And, the chemical that controls the dynamic we call physiology (or life) is water.
Understanding the atomic structure of water
To understand water’s chemistry we first must learn a bit about atoms. This is because water is composed of two types of atoms – hydrogen and oxygen.
For our purposes we can think of atoms as being made up of three components, protons, electrons, and neutrons. The number of protons that an atom has determines the unique nature of the matter formed by that atom. Hydrogen matter has one proton. Oxygen matter has eight protons. The number of electrons in each atom always equals the number of protons.
The electrical charge of each atom’s protons (positive) is strong enough to hold its own electrons (negative charges) in orbital close by. But, electrons move around the nucleus so rapidly that it is not physically possible to tell where any one electron is at any given point in time. To get around the issue of electron location, scientists have agreed to predict the movement of electrons based upon mathematical probability equations.
Probability equations calculate that an atom’s electrons form layers – each layer containing an optimal number of electrons. The result of assigning an optimal number of electrons to each layer is that most atoms end up with an outermost orbital layer that has more or less electrons than is optimal.
Sharing of electrons by two or more atoms is a common method for satisfying the need for an optimal number of electrons in the outermost orbital layer of all involved. Links called covalent molecular bonds occur between atoms when the outermost electron orbital of all participants becomes complete by the formation of a hybrid orbital.
In the case of the water molecule, oxygen shares its outer orbital layer with two electrons of the hydrogen atoms. A simplified drawing of the arrangement is presented above. The sharing, however, is not equal because oxygen’s eight protons exert a much greater positive force on water’s electrons than do hydrogen’s two protons.
Unequal sharing of electrons creates a polar water molecule with a partial negative charge around the oxygen atom – where the electrons are spending most of their time. Hydrogen electrons spend much less time near the hydrogen proton. This creates a partial positive charge at the hydrogen end of the molecule. The partial charges on opposite ends of the water molecules allow them to enter into weak bonds called hydrogen bonds with each other and with other similarly charged biologic molecules.
Why some molecules dissolve in water and others do not
The ability of polar water molecules to form hydrogen bonds is used to explain water’s ability to take some molecules into solution and ignore others. If water molecules encounter other molecules with a full or partial charge they will be electrically attracted to them and surround them.
Charged molecules that attract water are are said to be hydrophilic. Hydrophilic molecules occupy the fluid compartments of the body. Other molecules which have an aversion to water – the hydrophobic molecules – form biologic membranes. Physiology can be thought of as an organized cross-talk between watery compartments of hydrophilic molecules separated by biologic membranes composed of hydrophobic molecules.
For a complete beginner’s guide to water’s chemistry and its effect on human physiology, check out my easy read book “Physiology: Custom-Designed Chemistry.” It is available both as an e-book and as a paperback book.You may also like to read Buffering Body Alkalinity and Acidity and What is pH Balance?
From Science News there is The Secret To Walking On Water.
Do you have questions?
Please put your questions in the comment box or send them to me by email at DrReece@MedicalScienceNavigator.com. I read and reply to all comments and email.
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Margaret Thompson Reece PhD, physiologist, former Senior Scientist and Laboratory Director at academic medical centers in California, New York and Massachusetts and CSO at Serometrix LLC is now CEO at Reece Biomedical Consulting LLC.
Dr. Reece is passionate about helping students, online and in person, pursue careers in life sciences. Her books “Physiology: Custom-Designed Chemistry” (2012), “Inside the Closed World of the Brain” (2015) and the workbook (2017) companion to her online course “30-Day Challenge: Craft Your Plan for Learning Physiology” are written for those new to life science. More about her books can be found at amazon/author/margaretreece.
Dr. Reece offers a free 30 minute “how-to-get-started” phone conference to students struggling with human anatomy and physiology. Schedule an appointment by email at DrReece@MedicalScienceNavigator.com.by