News tagged with molecules
Related topics: cells , protein , atoms , cancer cells , cancer
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 and is available under the GNU Free Documentation License.
Australian scientists have charted the path of insulin action in cells in precise detail like never before. This provides a comprehensive blueprint for understanding what goes wrong in diabetes.
Medical research 5 hours ago | 4.5 / 5 (2) | 0 |
Scientists from Nanyang Technological University (NTU) and Lund University, Sweden, have bioengineered a novel molecule which has been proven to successfully kill tumour cells.
Cancer 7 hours ago | 5 / 5 (1) | 0
Researchers have pinpointed a catalytic trigger for the onset of Alzheimer's disease – when the fundamental structure of a protein molecule changes to cause a chain reaction that leads to the death of neurons ...
Alzheimer's disease & dementia May 20, 2013 | 5 / 5 (3) | 0 |
(Medical Xpress)—Inflammation is an important response in the body - it helps you to kill off invaders such bacteria that could cause a harmful infection. But if it's chronic or uncontrolled, inflammation can also cause ...
Inflammatory disorders May 14, 2013 | not rated yet | 0 |
How cells regulate their own function by "accelerating and braking" is important basic knowledge when new intelligent medicines are being developed, or when plant cells are tweaked to produce more bioenergy. In a study published ...
Medical research May 15, 2013 | 4 / 5 (1) | 0
"Borreliosis" or "Lyme disease" is caused by the bacterium "Borrelia burgdorferi". In Austria approximately 16,000 people fall ill with borreliosis annually following a tick bite. Roughly every fifth tick in Austria carries ...
Diseases, Conditions, Syndromes May 14, 2013 | not rated yet | 0