News tagged with molecules

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

Scientists 'un-can' the HIV virus

If the human immunodeficiency virus (HIV) is a bit like a hermetically sealed tin can no one has yet been able to break open, the good news is that researchers at the CHUM Research Centre, affiliated with the University of ...

May 04, 2015
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Study sheds new light on brain's source of power

New research published today in the journal Nature Communications represents a potentially fundamental shift in our understanding of how nerve cells in the brain generate the energy needed to function. The study shows neurons ...

Apr 24, 2015
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To stop cancer: Block its messages

The average living cell needs communication skills: It must transmit a constant stream of messages quickly and efficiently from its outer walls to the inner nucleus, where most of the day-to-day decisions are made. But this ...

Mar 30, 2015
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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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