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

Crystal with a twist: scientists grow spiraling new material

With a simple twist of the fingers, one can create a beautiful spiral from a deck of cards. In the same way, scientists at the University of California, Berkeley, and Lawrence Berkeley National Laboratory (Berkeley Lab) have ...

Neutrons get a wider angle on DNA and RNA to advance 3-D models

Scientists from the National Institute of Standards and Technology (NIST) and the University of Maryland are using neutrons at Oak Ridge National Laboratory (ORNL) to capture new information about DNA and RNA molecules and ...

Real-time analysis of MOF adsorption behavior

Researchers have developed a technology to analyze the adsorption behavior of molecules in each individual pore of a metal organic framework (MOF). This system has large specific surface areas, allowing for the real-time ...

Dinosaur bones are home to microscopic life

Bad news, Jurassic Park fans—the odds of scientists cloning a dinosaur from ancient DNA are pretty much zero. That's because DNA breaks down over time and isn't stable enough to stay intact for millions of years. And while ...

A prebiotic route to DNA

DNA may have appeared on Earth earlier than has hitherto been assumed. LMU chemists led by Oliver Trapp show that a simple reaction pathway could have given rise to DNA subunits on the early Earth.

Tracking life's first step: Two molecules 'awaken' brand new genome

Within hours after fertilization, a unique genome forms from chromosomes contributed by the egg and sperm. However, this new genome is initially inactive and must be "awakened" to begin the transcription of its DNA and start ...

Meteors help Martian clouds form

How did the Red Planet get all of its clouds? CU Boulder researchers may have discovered the secret: just add meteors.

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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.

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