News tagged with molecules

Related topics: cells · protein · atoms · cancer cells · cancer

After the epigenome: The epitranscriptome

Our genome is made up of 6,000 million pieces of DNA that combine four "flavors": A, C, G and T (Adenine, Cytosine, Guanine and Thymine). It is our Alphabet. But to this base we must add some regulation, just like the spelling ...

Mar 22, 2017
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A sweet vaccine against pneumonia

It may not take much to vaccinate against a particularly dangerous pathogen that causes pneumonia. A molecule consisting of three adjoined sugars is sufficient to protect against infections with highly virulent and antibiotic-resistant ...

Mar 10, 2017
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Boosting your own defenses against heart disease

A protein found in the heart that is known to be involved in cellular stress responses in cancer cells is now believed to play a critical role in the ability of cardiac cells to combat heart disease and recover from a heart ...

Mar 06, 2017
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Molecule

A molecule is defined as a sufficiently stable, electrically neutral group of at least two atoms in a definite arrangement held together by very strong (covalent) chemical bonds. Molecules are distinguished from polyatomic ions in this strict sense. In organic chemistry and biochemistry, the term molecule is used less strictly and also is applied to charged organic molecules and biomolecules.

In the kinetic theory of gases the term molecule is often used for any gaseous particle regardless of its composition. According to this definition noble gas atoms are considered molecules despite the fact that they are composed of a single non-bonded atom.

A molecule may consist of atoms of a single chemical element, as with oxygen (O2), or of different elements, as with water (H2O). Atoms and complexes connected by non-covalent bonds such as hydrogen bonds or ionic bonds are generally not considered single molecules.

No typical molecule can be defined for ionic crystals (salts) and covalent crystals (network solids), although these are often composed of repeating unit cells that extend either in a plane (such as in graphene) or three-dimensionally (such as in diamond or sodium chloride). The theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding. In glasses (solids that exist in a vitreous disordered state), atoms may also be held together by chemical bonds without any definable molecule, but also without any of the regularity of repeating units that characterises crystals.

This text uses material from Wikipedia, licensed under CC BY-SA

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