Facts About Hydrogen 2
The most abundant element in the universe, hydrogen is also a promising source of "clean" fuel on Earth. Named after the Greek words hydro for "water" and genes for "forming," hydrogen makes up more than 90 percent of all of the atoms, which equals three quarters of the mass of the universe, according to the Los Alamos National Laboratory. Hydrogen is essential for life, and it is present in nearly all the molecules in living things, according to the Royal Society of Chemistry. The element also occurs in the stars and powers the universe through the proton-proton reaction and carbon-nitrogen cycle.
The way in which carbon bonds to hydrogen, as well as other elements, such as oxygen and phosphorus, is called an organic molecule, which is a fundamental molecule that constitutes all life. Carbon is ultimately the cornerstone for life because its bonding patterns create complex structures that fold, bend, chain together or form rings. Carbon and hydrogen atoms are so prevalent in living organisms that there are molecules called hydrocarbons that are made up almost entirely of carbon and hydrogen.
Complex organic structures form large macromolecules, such as carbohydrates, lipids, proteins and nucleic acids, that are composed of thousands of atoms in the form of small units bonded together. Think of the winding double helix of DNA. This molecule is composed of two twisting strands bound together by hydrogen bonds. When DNA needs to unwind so that it can be read, the weak hydrogen bonds are broken. In carbohydrates, however, hydrogen atoms actually act as placeholders. Once the hydrogen is removed, two sugars bond together and form long repeating chains of a strongly linked unit. This also holds true for many fatty lipids and proteins.
Besides acting as an important structural element, hydrogen has a hand in nearly every single physiological function of living organisms due to its usefulness and abundance. In the task of digestion, hydrogen bonds with chlorine to form hydrochloric acid, which breaks down fat and protein in the stomach. In the task of aerobic respiration, the movement of free-floating hydrogen atoms helps stimulate the production of energy; this is similar to the way in which a water pump can create energy potential that can do work. Next to carbon, there is probably no other element used quite so often and for so many important functions.
Importance of Hydrogen Bonding 3
Hydrogen bonding is important in many chemical processes. Hydrogen bonding is responsible for water's unique solvent capabilities. Hydrogen bonds hold complementary strands of DNA together, and they are responsible for determining the three-dimensional structure of folded proteins including enzymes and antibodies.
Protein structure is partially determined by hydrogen bonding. Hydrogen bonds can occur between a hydrogen on an amine and an electronegative element, such as oxygen on another residue. As a protein folds into place, a series of hydrogen bond "zips" the molecule together, holding it in a specific three-dimensional form that gives the protein its particular function.