News tagged with molecules

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

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
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Trading in the scalpel for a sharper blade

Losing a breast or a lung to cancer leaves a scar, both physical and emotional. But even a biopsy to determine if a tumor is cancerous, or to track a tumor's response to drugs, brings short-term pain and can miss signs of ...

Feb 22, 2017
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Metabolism drives growth and division of cancer cells

The metabolic state of tumor cells contributes to signals that control their proliferation. German biochemist and Nobel Prize laureate Otto H. Warburg observed in the 1920s that tumor cells radically change their metabolism. ...

Feb 20, 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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