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Biology  Asymmetry  Atomic mass unit

Smallest part of any element that can exist independently
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A carbon atom bonded to four different atoms; also called chiral carbon atom. The bonds can be arranged in two different ways producing stereoisomers that are mirror images of each other. (Figure 2-6) ...

atom the smallest part of an element that can enter into various combinations with atoms of other elements.
atrium a thin-walled receiving chamber in which blood accumulates in fishes.

Atom one particle‚ one piece of an element
(a = not‚ without; tom = to cut)
Australian Realm the biogeographical realm including the continent of Australia and some of the surrounding islands
(austr(ali) = southern) ...

atom The smallest indivisible particle of matter that can have an independent existence.
atomic number The number of protons in the nucleus of an atom.

[Gk. atomos, indivisible]
The smallest unit of matter that retains the properties of an element.
atomic number ...

(Science: chemistry, physics, radiobiology) a particle of matter indivisible by chemical means. It is the fundamental building block of the chemical elements.

Van der Waals molecule
Diatomic molecule
History of the molecule
Chemical polarity
Molecular geometry
Covalent bond
Noncovalent bonding
list of compounds for a list of chemical compounds
List of molecules in interstellar space ...

atom The basic unit of matter; the smallest complete unit of the elements, consisting of protons, neutrons, and electrons.
atomic mass A mass unit determined by arbitrarily assigning the carbon-12 isotope a mass of 12 atomic mass units.

An atom with only one shell requires two electrons to complete its outer shell. Atoms with more than one shell require 8 electrons to complete their outer shells.
Periodic Table of the Elements ...

Every atom has a characteristic total number of covalent bonds that it can form, equal to the number of unpaired electrons in the outermost shell. This bonding capacity is called the atom's valence.

a hydrogen atom
an amino group (hence "amino" acid)
a carboxyl group (-COOH). This gives up a proton and is thus an acid (hence amino "acid")
one of 20 different "R" groups.

ion An atom that has lost or gained electrons from its outer shell and therefore has a positive or negative charge, respectively; symbolized by a superscript plus or minus sign and sometimes a number, e.g., H+, Na+1, Cl-2.

Ion: An atom or group of atoms that carries a positive or negative electric charge as a result of having lost or gained one or more electrons.
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Each carbon atom can form four bonds with other molecules
Carbon atoms form the skeleton of organic molecules ...

Each type of atom (element) has its own characteristic electronegativity. If the electronegativities of the two atoms in a bond are equal or close, then the electrons are shared more or less equally between them and the bond is said to be non-polar.

Each hydrogen atom is split into its constituent H+ (hydrogen ion) and electron. The electron is the part that actually gets passed down the chain from carrier to carrier. The H+, however, remains in the mitochondrial matrix.

Matter: acid, atom, base, catalyst, compound, covalent bond, ion, ionic bond, element, solution ...

radius of Hydrogen atom: 25pm
radius of Helium atom: 31 pm
10-10 m = 1 Ångström ...

The α-carbon atom has four different groups attached to it arranged at the points of a tetrahedron.

A unit of measurement equal to the mass of a hydrogen atom, 1.67 x 10E-24 gram/L (Avogadro's number). Death phase. The final growth phase, during which nutrients have been depleted and cell number decreases. (See Growth phase. Denature.

5' or 3' end The nucleoside residues which form nucleic acids are joined by phosphodiester linkages between the 3' C atom of one ribose moiety and the 5' C atom of the next.

Biology is a science full of terms and concepts that range from the hard-to-imagine, such as the structure of an atom, to those we see every day, such as the structure of our own face in the mirror. How are these ideas and concepts related?

At one end of each strand there is a phosphate group attached to the carbon atom number 5 of the deoxyribose (this indicates the 5' terminal) and at the other end of each strand is a hydroxyl group attached to the carbon atom number 3 of the ...

Okay so how do these guys play a part into each other, what do they look like in an atom? Well if we go to Neil's board model which is the simplest model to describe what an atom looks like.

It is composed of one oxygen atom and two hydrogen atoms. Each hydrogen atom is covalently bonded to the oxygen via a shared pair of electrons. Oxygen also has two unshared pairs of electrons.

The main determinants of secondary-ion formation are the sputtering rate (the rate of removal of the target atom by the primary ions), the ionization yield (the fraction of sputtered atoms that are ionized) and the local concentration of atoms.

The aldehyde or ketone group may react with a hydroxyl group on a different carbon atom to form a hemiacetal or hemiketal , in which case there is an oxygen bridge between the two carbon atoms, forming a heterocyclic ring.

Each atom of the living beings was originated in a star. The Iron of hemoglobin was generated in the moment when the atomic nuclei of a star fused to form heavier elements; for example Iron.

A weak electrostatic link between an electronegative atom (such as oxygen) and a hydrogen atom which is linked covalently to another electronegative atom; hydrogen bonding is what makes water stick to itself.
Deoxyribonucleic acid (DNA) ...

We're really reducing the question down to the smallest atom, and trying to understand at an anatomical level the structure of this receptor and how it's activated and how is it doing its job during this process of male sexual differentiation.

ion /EYE-on/ n. An atom or small molecule with a negative or positive charge.
ion channels /EYE-on/ n. Proteins, present in all cell membranes, governing the passage of specific ions between the interior and exterior of the cell.

The size of the carbon atom is based on its van der Waals radius.
Goodsell, David S (2002, February). Molecular Machinery: A Tour of the Protein Data Bank. Retrieved September 10, 2008, from Protein Data Bank.

Results from the fact that a preponderance of electrons can end up on one side of an atom.

Reduction - A reaction that results in the overall gain of electrons to a specific molecule or atom. Can occur with the addition of a hydrogen atom or by the removal of an oxygen atom.
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A reversible change in the position of a hydrogen atom in a molecule which results in the conversion of the molecule between different isomers. A shift between the keto group and a enoyl group in nucleotides can result in altered base-pairing.

Hydrogen bond. A relatively weak bond formed between a hydrogen atom (which is covalently bound to a nitrogen or oxygen atom) and a nitrogen or oxygen with an unshared electron pair.

A secondary feature of some proteins containing a zinc atom; a DNA-binding protein. (ORNL)
National Center for Biotechnology Information (NCBI) ...

Dalton - measure of molecular weight or mass. One hydrogen atom has mass of 1 Da. Proteins and other macromolecule molecular weights are usually measured in kDa or kD (kilodaltons) - 1000 Da.

The structure of living organisms is organized in a hierarchical, step-wise fashion. Small units make up larger units, that contribute to still larger units. For the purpose of this tutorial, the levels of organization from atom to the organism will ...

acids in a protein and hence protein function are determined by the genetic code.
Amino acids contain a basic amino (NH2) group, an acidic carboxyl (COOH) group and a side chain (R - of a number of different kinds) attached to an alpha carbon atom.

See also: See also: Molecule, Protein, Organ, Trans, Proteins

Biology  Asymmetry  Atomic mass unit

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