News tagged with molecules

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

How the brain reacts to sleep deprivation

In a new study, scientists from Forschungszentrum Jülich together with partners from the German Aerospace Center (DLR) have investigated the molecular changes with which the human brain reacts to exceptionally long wake ...

Apr 05, 2017
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Molecule stops fatal pediatric brain tumor

Northwestern Medicine scientists have found a molecule that stops the growth of an aggressive pediatric brain tumor. The tumor is always fatal and primarily strikes children under 10 years old.

Feb 27, 2017
popularity1707 comments 1

Neuroscientists now can read the mind of a fly

Northwestern University neuroscientists now can read the mind of a fly. They have developed a clever new tool that lights up active conversations between neurons during a behavior or sensory experience, such as smelling a ...

Dec 04, 2015
popularity783 comments 0

Unexpected mechanism behind chronic nerve pain

It has long been assumed that chronic nerve pain is caused by hypersensitivity in the neurons that transmit pain. Researchers at Karolinska Institutet in Sweden now show that another kind of neuron that normally allows us ...

Jun 01, 2017
popularity412 comments 0

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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