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Atom
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) ...

Table of atom charges and masses
So, for all these subatomic particles, we can characterize them by two basic traits. We characterize them by charge, and we characterize them by mass. Charge is pretty basic; it's just whether something is positive, negative or has no charge.

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.
auditory nerve the nerve within the ear that carries impulses to the brain for interpretation.

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

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

Atom the smallest part of an element that cannot be broken down further by chemical means.
ATP (Adenosine triphosphate) a molecule that acts as an energy carrier in all living cells.
Atrioventicular node (AVN) a specialized area of muscle between the atria and ventricles of the heart.

Atom
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
Molecular Hamiltonian
Molecular orbital ...

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.

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. It is the structure of the R group that determines which of the 20 it is and its special properties.

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.

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
Energy: cellular respiration, ATP, mitochondria, photosynthesis, glycolysis, glucose, metabolism, chlorophyll, Krebs cycle, electron transport chain ...

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. This arrangement is asymmetric and can occur in two different forms, or enantiomers, that are related to each other in the same way as an object and its image in a mirror.

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. Therefore each strand of DNA or RNA has a free 3' C at one end and a free 5' C at the other.

For our purposes, phosphorous has only one form, phosphate, which is a phosphorous atom with 4 oxygen atoms. This heavy molecule never makes its way into the atmosphere, it is always part of an organism, dissolved in water, or in the form of rock.

DNA methylation refers to the methylation of the carbon atom at position 5 of a cytosine (m5C), which mostly happens within CpG, CpHpG and CpHpH nucleotide patterns in eukaryotes [1]-[4].

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? What's the best way to learn and remember them?

Polychlorinated biphenyls (PCB's): A group of toxic, carcinogenic organic compounds containing more than one chlorine atom. PCB's were used in the manufacture of plastics and as insulating fluids in electrical transformers and capacitors.

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 deoxyribose (this indicates the 3' terminal).

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.

Structurally glucose is a hexagonal ring formed by one atom of oxygen and five atoms of carbon; a hydroxyl radical and a hydrogen atom bind in each carbon of the ring, except for one of the carbons bound to the oxygen of the ring; this carbon binds to a CH2OH radical.

Hydrogen bond
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.
References
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. The dispersion force which in fact is an induced dipole - induced dipole interaction depends on the polarisability of the interacting molecules and is inversely proportional to the sixth power of separation.

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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Tautomeric shift
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.

oxidation
A chemical process in which either electrons are lost from an atom, or oxygen is added to a molecule. Oxidation may also occur without the addition of oxygen if hydrogen is removed (dehydrogenation.)
Covered in BIOL1020 Lab 4 Cell Energetics I ...

A secondary feature of some proteins containing a zinc atom; a DNA-binding protein. (ORNL)
Sources:
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.

(1.) the sugar used in RNA is ribose, which contains one less oxygen atom than the deoxyribose in DNA, and: ...

The sequence of amino 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, Acids

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